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IEEE
May 2009, Vol. 47, No. 5
www.comsoc.org
MAGAZINE
Optical Communications: Highways of the Future
The First ITU-T Kaleidoscope Event:
“Innovations in NGN”
Topics in Automotive Networking
TOLE SUTIKNO - UNIVERSITAS AHMAD DAHLAN
YOGYAKARTA - INDONESIA
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Director of Magazines
Steve Gorshe, PMC-Sierra, Inc. (USA)
Editor-in-Chief
Nim K. Cheung, ASTRI, (Hong Kong)
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IEEE
Associate Editor-in-Chief
Steve Gorshe, PMC-Sierra, Inc. (USA)
Senior Technical Editors
Nirwan Ansari, NJIT (USA)
Tom Chen, Swansea University (UK)
Roch H. Glitho, Ericsson Research (Canada)
Andrzej Jajszczyk, AGH U. of Sci. & Tech. (Poland)
Torleiv Maseng, Norwegian Def. Res. Est. (Norway)
Technical Editors
Koichi Asatani, Kogakuin University (Japan)
Mohammed Atiquzzaman, U. of Oklahoma (USA)
Tee-Hiang Cheng, Nanyang Tech. Univ.
(Rep. of Singapore)
Jacek Chrostowski, Scheelite Techn. LLC (USA)
Sudhir S. Dixit, Nokia Siemens Networks (USA)
Nelson Fonseca, State U. of Campinas (Brazil)
Joan Garcia-Haro, Poly. U. of Cartagena (Spain)
Abbas Jamalipour, U. of Sydney (Australia)
Vimal Kumar Khanna (India)
Janusz Konrad, Boston U. (USA)
Nader Mir, San Jose State U. (USA)
Amitabh Mishra, Johns Hopkins University (USA)
Sean Moore, Avaya (USA)
Sedat Ölçer, IBM (Switzerland)
Algirdas Pakstas, London Met. U. (England)
Michal Pioro, Warsaw U. of Tech. (Poland)
Harry Rudin, IBM Zurich Res.Lab. (Switzerland)
Hady Salloum, Stevens Inst. of Tech. (USA)
Heinrich J. Stüttgen, NEC Europe Ltd. (Germany)
Dan Keun Sung, Korea Adv. Inst. Sci. & Tech. (Korea)
Naoaki Yamanaka, Keio Univ. (Japan)
Series Editors
Ad Hoc and Sensor Networks
Edoardo Biagioni, U. of Hawaii, Manoa (USA)
Silvia Giordano, Univ. of App. Sci. (Switzerland)
Automotive Networking and Applications
Wai Chen, Telcordia Technologies, Inc (USA)
Luca Delgrossi, Mercedes-Benz R&D N.A. (USA)
Timo Kosch, BMW Group (Germany)
Tadao Saito, University of Tokyo (Japan)
Design & Implementation
Sean Moore, Avaya (USA)
Integrated Circuits for Communications
Charles Chien (USA)
Zhiwei Xu, SST Communication Inc. (USA)
Stephen Molloy, Qualcomm (USA)
Network and Service Management Series
George Pavlou, U. of Surrey (UK)
Aiko Pras, U. of Twente (The Netherlands)
Topics in Optical Communications
Hideo Kuwahara, Fujitsu Laboratories, Ltd. (Japan)
Jim Theodoras, ADVA Optical Networking (USA)
Topics in Radio Communications
Joseph B. Evans, U. of Kansas (USA)
Zoran Zvonar, MediaTek (USA)
Standards
Yoichi Maeda, NTT Adv. Tech. Corp. (Japan)
Mostafa Hashem Sherif, AT&T (USA)
Columns
Book Reviews
Andrzej Jajszczyk, AGH U. of Sci. & Tech. (Poland)
Communications and the Law
Steve Moore, Heller Ehrman (USA)
History of Communications
Mischa Schwartz, Columbia U. (USA)
Regulatory and Policy Issues
J. Scott Marcus, WIK (Germany)
Jon M. Peha, Carnegie Mellon U. (USA)
Technology Leaders' Forum
Steve Weinstein (USA)
Very Large Projects
Ken Young, Telcordia Technologies (USA)
Your Internet Connection
Eddie Rabinovitch, ECI Technology (USA)
Publications Staff
Joseph Milizzo, Assistant Publisher
Eric Levine, Associate Publisher
Susan Lange, Digital Production Manager
Catherine Kemelmacher, Associate Editor
Jennifer Porcello, Publications Coordinator
Devika Mittra, Publications Assistant
MAGAZINE
May 2009, Vol. 47, No. 5
www.comsoc.org/~ci
TOPICS IN OPTICAL COMMUNICATIONS
SERIES EDITORS: HIDEO KUWAHARA AND JIM THEODORAS
34 GUEST EDITORIAL: OPTICAL COMMUNICATIONS — THE HIGHWAYS OF THE
FUTURE
38 A DYNAMIC IMPAIRMENT-AWARE NETWORKING SOLUTION FOR TRANSPARENT
MESH OPTICAL NETWORKS
The authors present a novel framework that addresses dynamic cross-layer network
planning and optimization while considering the development of a future transport
network infrastructure.
SIAMAK AZODOLMOLKY, DIMITRIOS KLONIDIS, IOANNIS TOMKOS, YABIN YE, CHAVA VIJAYA SARADHI,
ELIO SALVADORI, MATTHIAS GUNKEL, KOSTAS MANOUSAKIS, KYRIAKOS VLACHOS,
EMMANOUEL MANOS VARVARIGOS, REZA NEJABATI, DIMITRA SIMEONIDOU, MICHAEL EISELT,
JAUME COMELLAS, JOSEP SOLÉ-PARETA, CHRISTIAN SIMONNEAU, DOMINIQUE BAYART,
DIMITRI STAESSENS, DIDIER COLLE, AND MARIO PICKAVET
48 SIP-EMPOWERED OPTICAL NETWORKS FOR FUTURE IT SERVICES AND
APPLICATIONS
The authors present a novel application-aware network architecture for evolving
and emerging IT services and applications. It proposes to enrich an optical burst
switching network with a session control layer that can close the gap between
application requests and network control.
FRANCO CALLEGATI, ALDO CAMPI, GIORGIO CORAZZA, DIMITRA SIMEONIDOU, GEORGIOS ZERVAS,
YIXUAN QIN, AND REZA NEJABATI
55 IMPAIRMENT-AWARE ROUTING AND WAVELENGTH ASSIGNMENT IN
TRANSLUCENT NETWORKS: STATE OF THE ART
The authors propose a state of the art in the field of impairment-aware RWA
(IA-RWA), starting from the case of predictable traffic demands to the open
problem of stochastic traffic demands.
MAURICE GAGNAIRE AND SAWSAN AL ZAHR
62 MUPBED: A PAN-EUROPEAN PROTOTYPE FOR MULTIDOMAIN RESEARCH
NETWORKS
The main aspects of MUPBED provide deep insight into the most recent evolution of
control-plane-enabled optical networking toward multidomain integration.
JAN SPÄTH, GUIDO MAIER, SUSANNE NAEGELE-JACKSON, CARLO CAVAZZONI, HANS-MARTIN FOISEL,
MIKHAIL POPOV, HENRIK WESSING, MAURO CAMPANELLA, SALVATORE NICOSIA, JÜRGEN RAUSCHENBACH,
LUIS PEREZ ROLDAN, MIGUEL ANGEL SOTOS, MACIEJ STROYK, PÉTER SZEGEDI, JEAN-MARC UZE
72 TOWARD EFFICIENT FAILURE MANAGEMENT FOR RELIABLE TRANSPARENT
OPTICAL NETWORKS
The authors discuss failure management issues in TONs, the mechanisms involved,
and optical monitoring techniques.
NINA SKORIN-KAPOV, OZAN K. TONGUZ, AND NICOLAS PUECH
THE FIRST ITU-T KALEIDOSCOPE EVENT: “INNOVATIONS IN NGN”
GUEST EDITORS: YOICHI MAEDA AND MOSTAFA HASHEM SHERIF
80 GUEST EDITORIAL
82 A NEW GENERATION NETWORK: BEYOND THE INTERNET AND NGN
The author describes requirements and fundamental technologies to enable the
provision of a new generation network beyond the Internet and the next generation
network, both of which are based on IP protocols.
TOMONORI AOYAMA
88 OPEN STANDARDS: A CALL FOR CHANGE
The author reviews the different needs of specific groups of society and develops
10 different requirements for open standards.
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95 THE ARCHITECTURE AND A BUSINESS MODEL FOR THE OPEN HETEROGENEOUS
MOBILE NETWORK
The authors propose a revised architecture for TISPAN-NGN, which corresponds to
heterogeneous networks and open mobile markets, and presents a new business
model.
YOSHITOSHI MURATA, MIKIO HASEGAWA, HOMARE MURAKAMI, HIROSHI HARADA,
AND SHUZO KATO
102 DIFFERENTIAL PHASE SHIFT-QUANTUM KEY DISTRIBUTION
Quantum-key distribution has been studied as an ultimate method for secure
communications, and now it is emerging as a technology that can be deployed in
real fiber networks. The authors present their QKD experiments based on the
differential-phase-shift QKD protocol.
HIROKI TAKESUE, TOSHIMORI HONJO, KIYOSHI TAMAKI, AND YASUHIRO TOKURA
108 OPEN API STANDARDIZATION FOR THE NGN PLATFORM
The author outlines the importance of open APIs and the current achievements of
the standards bodies.The article concludes with a brief set of issues that standards
bodies must resolve in relation to these APIs.
CATHERINE E.A. MULLIGAN
TOPICS IN AUTOMOTIVE NETWORKING
SERIES EDITORS: WAI CHEN, LUCA DELGROSSI, TIMO KOSCH, AND TADAO SAITO
114 GUEST EDITORIAL
116 COMMUNICATION ARCHITECTURE FOR COOPERATIVE SYSTEMS IN EUROPE
The authors provide an overview of the technical developments in Europe and their
convergence toward a set of European standards. They address the current state of
the standardization activities and the potential scenarios and use cases, and they
describe the fundamental concepts of a European communication architecture for
cooperative systems.
TIMO KOSCH, ILSE KULP, MARC BECHLER, MARKUS STRASSBERGER, BENJAMIN WEYL,
AND ROBERT LASOWSKI
126 WAVE: A TUTORIAL
The IEEE has developed a system architecture known as WAVE to provide wireless
access in vehicular environments. This article gives an overview of the associated
standards. The presentation loosely follows the order of the layers of the open
systems interconnection model.
ROBERTO A. UZCATEGUI AND GUILLERMO ACOSTA-MARUM
134 VGSIM: AN INTEGRATED NETWORKING AND MICROSCOPIC VEHICULAR
MOBILITY SIMULATION PLATFORM
Simulation is the predominant tool used in research related to vehicular ad hoc
networks. The authors present the key requirements for accurate simulations that
arise from the various applications supported by VANETs, and they review the
current state-of the-art VANET simulation tools.
BOJIN LIU, BEHROOZ KHORASHADI, HAINING DU, DIPAK GHOSAL, CHEN-NEE CHUAH,
AND MICHAEL ZHANG
142 MODELING URBAN TRAFFIC: A CELLULAR AUTOMATA APPROACH
The authors introduce a new cellular automata approach to construct an urban
traffic mobility model. Based on the developed model, characteristics of global
traffic patterns in urban areas are studied. The results show that different control
mechanisms used at intersections such as cycle duration, green split, and
coordination of traffic lights have a significant effect on intervehicle spacing
distribution and traffic dynamics.
OZAN K. TONGUZ, WANTANEE VIRIYASITAVAT, AND FAN BAI
152 NEMO-ENABLED LOCALIZED MOBILITY SUPPORT FOR INTERNET ACCESS IN
AUTOMOTIVE SCENARIOS
The authors survey the major existing approaches and proposes a novel architecture
to support mobile networks in network-based, localized mobility domains. Their
architecture enables conventional terminals without mobility support to obtain
connectivity from either fixed locations or mobile platforms (e.g., vehicles) and
move between them, while keeping their ongoing sessions.
IGNACIO SOTO, CARLOS J. BERNARDOS, MARIA CALDERON, ALBERT BANCHS, AND ARTURO AZCORRA
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THE PRESIDENT’S PAGE
STEERING THE SOCIETY’S FLAGSHIP CONFERENCES
T
ries and then Bellcore, where he was Exeche IEEE Communications Society has
utive Director of Multimedia Communicaan outstanding portfolio of more than
tions Research.
40 conferences that it either sponsors or
cosponsors each year. In many ways, this is
Dr. Heinrich Stüttgen is Vice President of
like a “fleet” of events that “sail” around the
NEC Europe Ltd., responsible for NEC
Europe’s research and standardization activiworld as an important networking venue for
ties in IT and telecommunications technoloour global community. Leading this fleet are
gies. He heads the NEC Laboratories in
ComSoc’s two flagship conferences, ICC
Europe with more than 120 scientists and
(IEEE International Conference on Commuengineers based in Heidelberg, Bonn (Gernications) and IEEE GLOBECOM (IEEE
many) and Acton (UK). He has been a MemGlobal Communications Conference). Each
ber at Large of the ComSoc Board of
conference is held annually, ICC typically in
Governors (2004 - 2006) and has been chairMay-June and GLOBECOM typically in
DOUG ZUCKERMAN
November-December. In addition to being
ing the GLOBECOM/ICC Technical Strategy
the Society’s two main events,
Committee since 2005. He also
serves as Technical Program
spanning the entire breadth of
Vice-Chair of ICC 2009 in Drescommunications topics, they also
den, Germany.
host most of its committee, board
and council meetings, including
NEED FOR STEERING
that of the Board of Governors.
Given the significance of these
Over the years IEEE
two flagship events to the ComGLOBECOM and ICC have
munications Society, it is imporbecome the largest telecommutant to consistently, and
nications research conferences in
efficiently, provide a high quality,
the world. They are ComSoc’s
meaningful event year after year
flagship conferences covering
with minimal re-invention each
the whole breadth of ComSoc’s
time. Steering these flagships are
technical interests, from wireless
two standing committees of the
and optical transmission techROB FISH
HEINER STÜTTGEN
ComSoc Board of Governors:
nologies up through communica•GIMS - GLOBECOM/ICC
tions software, services and
Management and Strategy, and
security, regularly attracting over a thousand attendees, with
• GITC - GLOBECOM/ICC Technical Content.
2,000 to 3,000 papers submitted to each of them. Around the
Rob Fish chairs GIMS, while Heiner Stüttgen chairs
years 2000 to 2004, the organic growth of these conferences
GITC. It is my pleasure to share this month’s column with
and the rapid changes in telecommunications technologies
Rob and Heiner, who will give you an overview of these two
led to a situation in which it became increasingly difficult to
committees, including their role in setting the course for
organize a well structured, high quality, and attractive techfuture conference venues as well as timely and relevant technical program. This made it difficult to serve the whole
nical programs.
telecommunications community while also being financially
Dr. Robert S. Fish is Chief Product Officer and Senior
solid to help support ComSoc’s finances, which suffered
Vice President of Mformation Technologies, Inc., a leadseverely after the implosion of the Internet bubble. Based on
ing vendor of device management solutions to the mobile
these observations, ComSoc’s Board of Governors ran a task
communications industry. He is responsible for more than
force to identify means to improve GLOBECOM and ICC
200 engineers engaged in software development, quality
from a technical as well as from administrative and financial
assurance, systems engineering, and program management
perspectives. Based on the recommendations of the task
activities at Mformation’s locations in the United States,
force, two new standing committees were established: a) the
United Kingdom, and India. Rob received his Ph.D. from
GLOBECOM/ICC Management and Strategy Committee to
Stanford University. He is currently a member of the
improve the organization, administration and financial manIEEE Communi- cations Society’s Board of Governors,
agement of the two flagship conferences; and b) the
Secretary of the ComSoc Standards Board, and has been
GLOBECOM/ICC Technical Content Committee to improve
the Chair of the GLOBECOM/ICC Management and
their technical quality and content.
Strategy Committee (GIMS) since 2008. Dr. Fish is also
GIMS: ASSURING A SOUND INFRASTRUCTURE
chair of the Steering Committee of ComSoc’s annual Consumer Communications and Networking (CCNC) conferGIMS’s principal function is to assure that the overall
ence. From 2004-2007 he was a member of the Corporate
conference “infrastructure” is sound. This includes overseeing
the general management (including the finances) and planAdvisory Group (CAG) of the IEEE Standards Associaning the strategic directions for GLOBECOM and ICC.
tion. Previously, Dr. Fish was Managing Director and Vice
GIMS serves as the institutional “memory” for the conferPresident of Panasonic’s Research and Development Laboratories in the U.S. Earlier, Dr. Fish was at Bell Laboratoences, making sure that their activities are planned for the
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FIGURE 1: ICC 2009 in Dresden.
benefit of ComSoc and its members. Each conference has its
own organizing committee (OC) and these OC’s report to
GIMS. As a committee, GIMS has nine members, consisting
of the chair, vice-chair, operations manager, and six other
members. One of these other members is the current chair of
GITC (and similarly the chair of GIMS is a current member
of GITC). This is done so that the work of GIMS and GITC
can remain closely coordinated. These members are appointed by the GIMS chair according to the rules in the GIMS
charter. Some members must be past members of GLOBECOM and ICC organizing committees, and others are appointed at-large with the advice and consent of the ComSoc Vice
President for Conferences.
GIMS does not attempt to run any given GLOBECOM or
ICC. That is the right and responsibility of the organizing
committee that is in charge of a particular conference. However, GIMS does appoint an advisor to each prospective conference to help with any issues that may come up during the
course of the three or four years between the time an organizing committee is formed and the time the actual conference
takes place.
Each member of GIMS (except for the GITC chair) also
chairs a working group dedicated to some aspect of the promotion and management of GLOBECOM and ICC. The
working groups help guide policies and activities for finance,
marketing, site selection, co-located events, operations, exposition, OC deliverables, and patronage. They also make recommendations to GIMS on the policies and procedures that
GIMS as a whole may vote to adopt.
One GIMS function of great interest is future site selection. This is usually tied in with identifying the organizing
committee that will make the conference happen. How this is
done is outlined in great detail on the GIMS website
(www.comsoc.org/GIMS). Future venues are typically identified three to four years out, based on “bids” by interested proponents. If you are interested in pursuing this with your local
Chapter or Section, please feel free to contact the GIMS chair
as outlined on the website.
GIMS could never do its work without close coordination
with the ComSoc staff members who work in the ComSoc
Meetings and Conferences group. Bruce Worthman, who is
the Director of Conferences, Finance and Administration on
ComSoc’s staff, also serves as the treasurer or co-treasurer of
every GLOBECOM and ICC, and along with the GIMS
Finance Working Group, helps to plan and maintain the
financial integrity of each conference.
Looking toward the future, GIMS is trying to serve our
members globally by having conferences in many great international cities. In addition, we are looking to serve our members in new and exciting ways, such as enhancing the
conferences through our co-located exposition and other
events of interest to attendees. GIMS hopes to grow our flagship conferences so that all ComSoc members will find something of value in attending.
GITC: ASSURING QUALITY AND CONTENT
The GITC committee consists of 10 members including
several experienced technical program chairs. However, GITC
meetings are “open” to the interested community, and GITC
greatly values input and support from volunteers, even if they
are not (yet) official GITC members. GITC first met at the
GLOBECOM 2005 Conference in St. Louis. There it was recognized that a main source of problems was the re-invention
of the structure and processes followed to organize the
GLOBECOM/ICC technical programs from event to event.
This led to inconsistencies in the program and confusion
among authors and attendees. Over the past several years,
GITC has spent much time in meetings and email discussions
to resolve many of the recognized problems.
By now a list of 11 standard symposia with clear scopes
have been defined, so that researchers know what can be submitted to which symposium. In addition, it has become easier
to find qualified reviewers within the new structure. Beyond
this, it also helps conference attendees find all presentations
of their interest easily by looking at only one or two symposia.
A standard review process has been defined that is used consistently from conference to conference. This helps assure a
consistent level of quality between different symposia and
from conference to conference. Over time this also makes the
job of the reviewers easier, as they do not have to learn a new
process again and again.
In the past there were many discussions between Technical
Program (TP) chairs and ComSoc’s Technical Committees,
the technical sponsors of the various symposia. Now the roles
and interactions of TP Chair and Technical Committees have
been defined, so that Technical Committees can more properly contribute their expertise and energy. A careful balance
between helping and guiding vs. micro-managing the TP
chairs is required and, based on the positive feedback of
recent TP chairs, the goal has been achieved.
Although the 11 symposia represent the technical backbone of the GLOBECOMs and ICCs, other program ele-
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FIGURE 2: GLOBECOM 2009 in Hawaii.
ments such as tutorials, workshops, panel discussions, and
keynotes greatly contribute to the technical appeal of these
conferences. In its first years GITC has developed a framework including selection criteria and quality control of tutorials, as well as a structure and a format for the less formal
workshops, including a platform for formal workshop proceedings. ICC 2009, which is coming up in June, has already
seen considerably increased interest in workshop contributions
based on the new format. The demand for a less formal, more
timely discussion platform offering formal publications in
addition to panels and invited presentations on hot topics was
quite obvious, but so far had not been well exploited.
Although many problems have been addressed, the work is
far from over. The current focus of GITC is on documenting
and communicating the defined processes to the relevant players. Needless to say, many of the guidelines need to be
reviewed periodically, to ensure that they are adapting to a
changing environment.
SHIFTING FOCUS TOWARD INDUSTRY
Last but certainly not least, the current focus is shifting to
the industry program. It is a regretful fact that relatively few
industry engineers attend our two flagship conferences,
which are often viewed as events of academic interest. However, ComSoc’s constituency consists of a large fraction of
engineers coming from industry. Surely, we can serve them
better than we do today. Therefore, GITC and GIMS are
currently studying how to better serve this important community. Program elements such as keynotes, panels, industry
forums, and exhibitions are under study and offer great
potential to bring back industry participants to our flagship
conferences. However, it is obvious that these elements
require processes that are different from the scientific program. Beyond that, it is also obvious that defining a good
industry program requires more volunteers from the industrial community than we have today.
ON THE HORIZON
On the horizon for this year are ICC in Dresden on June
14-18 (see Figure 1), and GLOBECOM in Honolulu on
November 30 - December 4 (see Figure 2). Further informa_______
tion is available at www.ieee-icc.org and www.ieeeglobecom.org.
_________ We invite you to not only attend these flagship
events, but to sit in on the GIMS and GITC meetings to see
how these important flagships of ComSoc’s conference “fleet”
are being steered.
CALL FOR PAPERS
R ADIO
IEEE
C OMMUNICATIONS
COMPONENTS, SYSTEMS, and NETWORKS
A QUARTERLY SERIES
IN
IEEE COMMUNICATIONS MAGAZINE
IEEE Radio Communications will cover components, systems and networks related to radio frequency (RF) technology. Articles will be in-depth, cutting-edge tutorials, emphasizing state of the art design solutions involving physical
and other lower-layer issues in radio communications, including RF, microwave and radio-related wireless communications topics.
IEEE Radio Communications will emphasize practical solutions and emerging research for immediate and practical
applications for innovative research, design engineers, and engineering managers in industry, government, and academic pursuits. Articles will be written in clear, concise language and at a level accessible to those engaged in the
design, development, and application of products, systems, and networks.
A rigorous peer review process will ensure that only the highest quality technical articles are published, keeping to
the high IEEE standard of technical objectivity that precludes marketing and product endorsements.
Manuscripts must be submitted through the magazine’s submissions Web site at
http://commag-ieee.manuscriptcentral.com/
On the Manuscript Details page please click on the drop-down menu to select
Radio Communications Series
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____________________________________________
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CONFERENCE CALENDAR
2009
■ IEEE ICC 2009 - IEEE Int’l.
Conference on Communications,
14-18 June
MAY
Dresden, Germany. Info: http://www.com__________
soc.org/confs/icc/2009/index.html
● MC-SS 2009 - 7th Int’l. Workshop
on Multi-Carrier Systems & Solutions, 5-6 May
Herrsching, Germany. Info: http://www.
mcss2009.org
● PV 2009 - 17th Int’l. Packet Video
Workshop, 11-12 May
Seattle, WA. Info: http://www.pv2009.com
● CNSR 2009 - Communication
Networks and Services Research
2009, 11-13 May
Hong Kong, China. Info: http://www.ieee.org.
hk/asid2009/
________
■ SECON 2009 - IEEE Communications Society Conference on Sensor
and Ad Hoc Communications and
Networks, 22-26 June
Rome, Italy. Info: http://www.ieee-secon.
com/2009
● ITU K-IDI 2009 - ITU-T Kaleidoscope 2009 — Innovations for Digital
Inclusion, 31 Aug.-1 Sept.
Mar Del Plata, Argentina. Info: http://www.itu.
int/ITU-T/kaleidoscope2009/
_________________
● GIIS 2009 - Global Information
Infrastructure Symposium, 23-25
June
Hammamet, TN. Info: ___________
http://www.ieee-
■ IEEE EDOC 2009 - 13th IEEE Int’l.
Enterprice Computing Conference,
31 Aug.-4 Sept.
giis.org/
_____
Auckland, New Zealand. Info: https://www.se.
________
auckland.ac.nz/conferences/edoc2009/
_______________________
Moncton, NB, Canada. Info: http://www.cnsr.
info/events/csnr2009
____________
● MEDHOCNET 2009 - IFIP MedHoc-Net 2009, 29 June-2 July
SEPTEMBER
■ IEEE CTW 2009 - IEEE Communication Theory Workshop, 11-14 May
Haifa, Israel. Info: http://www.ee.technion.
ac.il/med-hoc-net2009/index.htm
____________________
St. Croix, U.S. Virgin Islands. Info: http://www.
ieee-ctw.org/2008/index.html
■ IEEE CQR 2009 - 2009 IEEE Int’l.
Workshop, Technical Committee on
Communications Quality and Reliability, 12-14 May
Naples, FL. Info: http://www.ieeee-cqr.org/
JULY
● NGI 2009 - 5th EURO-NGI Conference on Next Generation Internet
Networks, 1-3 July
Aveiro, Portugal. Info: http://www.ngi2009.eu
■ IEEE WiMAX 2009 - 2009 IEEE
Mobile WiMAX Symposium, 9-11
July
JUNE
■ IM 2009 - IFIP/IEEE Int’l.
Symposium on Integrated Network
Management, 1-5 June
Napa, CA. Info: _______________
chenkc@cc.ee.ntu.edu.tw
● ISWCS 2009 - Int’l. Symposium on
Wireless Communication Systems,
7-10 Sept.
Siena, Tuscany, Italy. Info: http://www.iswcs.
org/iswcs2009/
● ICUWB 2009 - 2009 IEEE Int’l.
Conference on Ultra Wideband, 911 Sept.
Vancouver, BC, Canada. Info: http://www.
ICUWB2009.org
● IEEE LATINCOM 2009 - IEEE Latin
America Communications Conference
Hempstead, NY. Info: http://www.iee-im.org/
■ IWQoS 2009 - Int’l. Workshop on
Quality of Service 2009, 13-15 July
Medellin, Antioquia, Colombia. Info:
http://www.ieee.org.co/~comsoc/latincom
2009
___
Charleston, NC. Info: http://iwqos09.cse.sc.edu
● ICUFN 2009 - 1st Int’l. Conference
on Ubiquitous and Future
Networks, 7-9 June
● NDT 2009 - 1st Int’l. Conference
on Networked Digital Technologies,
28-31 July
● WiCOM 2009 - 2009 Int’l. Conference on Wireless Communications,
Networking and Mobile Computing, 24-26 Sept.
Hong Kong, China. Info: http://www.icufn.org
Ostrava, Czech Republic. Info: ____
http://
arg.vsb.cz/NDT2009/
_____________
● ConTEL 2009 - 10th Int’l.
Conference on Telecommunications, 8-10 June
● IWCLD 2009 - Int’l. Workshop on
Cross Layer Design 2009, 11-12
June
Mallorca, Spain. Info: http://www.iwcld2009.org
AUGUST
● ICCCN 2009 - 18th Int’l. Conference on Computer Communications
and Networks, 2-6 Aug.
San Francisco, CA. Info: http://www.icccn.org/
icccn09/
_____
■ Communications Society sponsored or co-sponsored conferences are indicated with a square
before the listing; ● Communications Society technically co-sponsored or cooperating conferences are indicated with a circle before the listing. Individuals with information about upcoming
conferences, calls for papers, meeting announcements, and meeting reports should send this
information to: IEEE Communications Society, 3 Park Avenue, 17th Floor, New York, NY
10016; e-mail: _____________
p.curran@comsoc.org; fax: +1-212-705-8999. Items submitted for publication will
be included on a space-available basis.
10
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Beijing City, China. Info: ___________
http://www.wicommeeting.org/
_______
OCTOBER
Zagreb, Croatia. Info: http://www.contel.hr
IEEE
● ICASID 2009 - Int’l. Conference
on Anti-Counterfeiting, Security
and Identification in Communication, 20-22 Aug.
■ ATC 2009 - 2009 Int’l. Conference
on Advanced Technologies for
Communications, 12-14 Oct.
Hai Phong, Vietnam. Info: http://ww.atc09.org
● ICFIN 2009 - 1st Int’l. Conference
on Future Information Networks,
14-17 Oct.
Beijing, China. Info: http://conference.bjtu.
edu.cn
____
■ MILCOM 2009 - 2009 IEEE Military
Communications Conference, 16-21
Oct.
Boston, MA. Info: http://www.milcom.org
(Continued on page 14)
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BOOK REVIEWS
EDITED BY ANDRZEJ JAJSZCZYK
AD HOC MOBILE WIRELESS
NETWORKS: PRINCIPLES, PROTOCOLS,
AND APPLICATIONS
SUBIR KUMAR SARKAR, T. G.
BASAVARAJU, C. PUTTAMADAPPA,
AUERBACH PUBLICATIONS, 2008,
ISBN 978-1-4200-6221-2, HARDCOVER,
312 PAGES
REVIEWER: MAREK NATKANIEC
Mobile wireless ad hoc networks
(MANETs) are a rapidly evolving
telecommunications technology. Their
popularity is connected with their easy
deployment and fast configuration.
These features make them ideal for
average users, Internet service providers,
and reacting to emergency situations in
which normal communication is impossible. They can be used with success in
disaster areas (earthquake, flood, hurricane), military training grounds, schools;
at conferences, hotels, airports, houses,
and so on. This kind of network is the
best alternative for developing countries, and everywhere communications
infrastructure does not exist. Ad hoc
networks clearly differ from the traditional cable infrastructure. However, in
comparison with wired networks, ad hoc
networks offer much smaller bandwidth;
hence, their design requires much more
attention. What is more, constantly
changing and unpredictable channel
conditions, hidden and exposed node
problems, varying network load, changeable device performance, different transmission and sensing ranges, and mobility
of ad hoc networks make it an even
more difficult task.
This book is targeted at a variety of
readers with different levels of wireless
network knowledge. The presented material is in its majority focused on different
layer protocols for ad hoc networks. It
covers practical applications review and
cross-layer design aspects as well as quality of service (QoS), energy, and mobility
issues. The book consists of 10 chapters,
and begins with a short introduction to
wireless and ad hoc networks. This chapter describes wireless network fundamentals covering Bluetooth, IrDA, HomeRF,
IEEE 802.11 (WiFi), and IEEE 802.16
(WiMAX) standards. Moreover, it intro-
__________
duces the Mobile IP concept. The main
technical and research challenges of ad
hoc networks are also considered in the
first chapter.
Chapter 2 overviews medium access
control (MAC) layer protocols. The
need for new MAC protocols is presented at the beginning, and then classification of MAC protocols is discussed. A
number of well-known MAC protocols
for MANETs (MACA, MACA-BI, DCF
of IEEE 802.11, GAMA-PS, Multichannel CSMA, DBTMA, HRMA, MMAC,
DCA-PC, PAMAS, DPSM, PCM,
PCMA) are briefly described. Several
issues like collision resolution, power
conservation, multiple channels, and
directional antennas usage are covered.
Chapter 3 focuses on routing protocols. Design issues of routing protocols
for ad hoc networks are highlighted.
Classification of routing protocols is
also discussed. Several proactive, reactive, and hybrid routing protocols are
presented in detail. This allows the
reader to understand different characteristics of each routing protocol as well
as to find its relationship with others.
Multicast ad hoc routing protocols are
the topic of Chapter 4. These allow the
creation and maintenance of a multicast
tree or mesh to assume quick reactions to
network topology changes and minimization of packet loss. The classification of
multicast routing protocols based on topology, initialization of the multicast session,
the topology maintenance mechanism, and
zone routing are showed. The most important multicast protocols, including multicasting with QoS guarantees, and
energy-efficient and application-dependent
protocols, are characterized in this chapter.
Chapter 5 is devoted to transport
protocols. It is shown that the Transmission Control Protocol (TCP) in most of
its versions is inappropriate for wireless
networks because of high bit error rates,
hidden and exposed stations, path asymmetry, multihop communications, and
mobility problems. TCP performance
and route failures over MANETs are
studied. A number of recently proposed
transport layer end-to-end approaches
to improve TCP’s performance are
explained and compared at the end.
In Chapter 6 QoS issues and challenges are addressed. Each OSI/ISO
layer is briefly analyzed in terms of the
QoS at the beginning; then a classification of QoS solutions is presented. The
authors point out some factors that
increase the complexity of QoS support
in the MANET environment. Furthermore, the selected QoS-capable MAC
_________
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USB 2.0 and RJ 45 Industrial Ethernet connection
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USB 2.0 and RJ 45 Connector Systems from
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Tel. + 1 919 460 8800
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E-mail ________
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14
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BOOK REVIEWS
(Continued from page 12)
and network layer protocols are explored.
The Flexible QoS Model for MANETs
(FQMM) and INSIGNIA framework
description finishes this chapter.
Chapter 7 presents energy management systems for ad hoc wireless networks.
How to manage energy efficiently assuming limited power sources in MANET
nodes is discussed. The IEEE 802.11
power-saving mode is overviewed here.
This chapter also deals with different energy-efficient routing protocols, transmission
power management schemes, and control.
Chapter 8 investigates the mobility
models for multihop networks. Specifically, it shows how the performance
results of an ad hoc network protocol
drastically change as a result of
c h an g i n g the s imu l ated mo bil ity
model. This chapter contains results
that come from the authors’ own
research. The random waypoint
mo b i l i t y, reference po int gro u p,
Gauss-Markov, and Manhattan models were used in evaluation of the
routing protocol’s performance.
Chapter 9 emphasizes the cross-layer
design issues. After reading this chapter,
it seems that cross-layer design can be a
suitable approach for standalone wireless
ad hoc networks and dedicated for use
with only a single application; thus, we
do not have to worry about interoperability issues. The authors suggest that
aggressive use of cross-layer design is not
a reasonable idea. As an example, the
design of transmit power control protocol for wireless networks is analyzed.
The last chapter (Chapter 10)
addresses applications and recent developments in ad hoc networking. The
most typical applications are presented.
The challenges, with special attention
on security, are exemplified.
In summary, the book is a considerable source of information about
MANET protocols and principles. It
contains a lot of information, mostly
gathered from international conferences, RFCs, and journal papers.
Extensive bibliography sections for
deeper reading are attached to the end
of all chapters. Each chapter contains a
short introduction in which the motivation can be found. In addition, at the
end of each chapter final conclusions
are given that summarize the presented
knowledge. Some illustrations help
understand important topics. Unfortunately, the reader can find some overlap in material among different
chapters; then again, this makes it possible to read each chapter independently. The book should be attractive to
students and graduate students as well
as lecturers and network engineers.
CONFERENCE CALENDAR/continued
● DRCN 2009 - 7th Int’l. Worksho
on the Design of Reliable Communications Networks, 26-29 Oct.
Washington, DC. Info: http://www.drcn.us/
● ICIN 2009, 26-29 Oct.
Bordeaux, France. Info: http://www.icin.biz/
NOVEMBER
● AH-ICI 2009 - First Asian
Himalayas Int’l. Conference on
Internet, 3-5 Nov.
Kathmandu, Nepal. Info: _________
http://www.ahici.org/ah-ici2009
__________
● COMCAS 2009 - 2009 Int’l. Conference on Microwaves, Communications, Antennas and Electronic
Systems, 9-11 Nov.
Tel Aviv, Israel. Info: http://www.comcas.org
● IEEE-RIVF 2009 - 2009 IEEE-RIVF
Int’l. Conference on Computing and
Communication, 13-17 Nov.
Danang, Vietnam. Info: http://www.rivf.org
■ IEEE GLOBECOM 2009 - IEEE Global Communications Conference, 30
Nov.-4 Dec.
Honolulu, HI. Info: _____________
http://www.ieee-globecom/2009
______
DECEMBER
● ICICS 2009 - 7th Int’l. Conference
on Information, Communications
and Signal Processing, 7-10 Dec.
Macau, China. Info: http://www.icics.org/2009/
■ ANTS 2009 - 2009 3rd Int’l. Symposium IEEE Advanced Nteworks
and Telecommunications Systems,
14-16 Dec.
New Delhi, India. Info: ___________
http://www.ieeeants.org
_____
2010
JANUARY
■ IEEE CCNC 2010 - IEEE Consumer
Communications and Networking
Conference, 9-12 Jan.
Las Vegas, NV. Info: http://www.ieee___________
ccnc.org/
_____
APRIL
■ IEEE DYSPAN 2010 - IEEE Int’l.
Symposium on Dynamic Spectrum
Access Networks, 6-9 April
Singapore. Info: http://www.ieee-dyspan.org
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NEW PRODUCTS
PHOENIX™1200 TUNABLE LASER
MODULE
Luna Technologies
Luna Technologies, a division of
Luna Innovations Incorporated,
announces the PHOENIX™ 1200 tunable swept laser module with picometer
accuracy and the industry’s first integrated wavemeter. The PHOENIX™
1200 C-band laser has NIST-traceable
accuracy and sub-picometer resolution,
making it ideal for fiber optic test and
measurement, spectroscopy and fiber
bragg grating-based sensing applications.
The PHOENIX™ 1200 also comes
standard with a miniaturized, internal
NIST-traceable wavemeter, giving it the
highest accuracy available while maintaining its compact footprint. The package includes a software development kit
and USB interface that allow for easy
customization of applications in development and manufacturing environments. www.lunatechnologies.com
MP1800A SIGNAL QUALITY
ANALYZER
Anritsu
Anritsu Company extends the
100Gbps test capabilities of its
MPl800A Signal Quality Analyzer with
the introduction of pre-code/decode
software that has been developed to
support the latest optical phase modulation schemes, including DP-QPSK,
DQPSK, DPSK, and ODB, used in Next
Generation Networks (NGNs). The
new software package complements the
2-channel MUX/DEMUX configuration of the MP1800A to provide device
manufacturers with a flexible, highly
accurate test solution for evaluating
high-speed optical modulators and
transponders.
The pre-code and decode functions
of the MX180000A-001/002 option help
reduce 100G and 40G core-network
R&D costs as well as time to market by
supporting fully automatic generation
of modulation signals needed to evaluate 100G DP-QPSK, and 40G DQPSK,
DPSK, and ODB optical modulation
technologies. The pre-code function
automatically generates 100G DPQPSK, and 40G DQPSK, DPSK, and
ODB modulation signals for evaluating
optical modulators. The decode function is for evaluating the logic of precoders in optical modules.
All electrical, modulation, and
demodulation signals required for evaluating DP-QPSK, DQPSK, DPSK and
ODB devices are generated automatically by the MP1800A. The test solution
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provides a number of benefits, including eliminating modulation pattern editing and programming, and reducing the
time necessary for evaluating modulation errors and error rates.
Hardware-based generation of modulation signals produces pure PRBS31
signals without pattern length restrictions, so the MP1800A can conduct
highly reliable evaluations using highload pseudo random patterns that closely emulate live traffic. Users can vary
the skew between I and Q signals with
high resolution over a wide range (±64
UI, 2 mUI steps) to confirm the input
skew margin of DQPSK modulators
with confidence.
www.us.anritsu.com
INDUSTRY-FIRST OPTICAL
MODULATION ANALYZER
Agilent Technologies
The advanced optical modulation
schemes carry information in amplitude, phase and polarization. To develop new optical transmitters and
receivers it is necessary to analyze
amplitude and phase behavior of these
signals in two orthogonal polarization
states. Currently available test instruments are only capable of analyzing the
amplitude of the optical signal, leaving
a gap in the test instrument market.
The N4391A optical modulation analyzer closes this gap by offering new
analysis tools such as constellation
plane display of the demodulated signal and error vector magnitude analysis
displaying the error compared to an
ideal signal.
www.agilent.com/find/oma_video
IC SOLUTION FOR 16G FIBRE
CHANNEL SFP+
Gennum
Agilent Technologies Inc. has introduced a time-domain based optical
modulation analyzer offering in-depth
analysis of amplitude and phase-modulated optical signals. This optical test
instrument was developed in close
cooperation with Agilent Laboratories,
the central research arm of Agilent
Technologies. It is based on widebandwidth, polarization-diverse coherent optical receiver technology, the
Agilent 89600 vector signal analysis
software (VSA), and Agilent’s highspeed real-time data acquisition unit
called the Infiniium Series 90000 oscilloscope.
It is the first time-domain-analysisbased coherent detection system and
offers highest flexibility and in-depth
analysis of amplitude and phase modulated optical signals in a turn-key solution, allowing scientists and engineers
to rapidly test their ideas.
Since the broad deployment of the
Internet, service providers have seen a
continuous increase in demand for
transmission capability. This is driving
today’s transmission rates of 10 Obis
toward 40 Gb/s and 100 Gb/s in the
next few years.
The challenge put to the optical
industry is how to fit a transmission rate
of 100 Gb/s into the legacy 500Hz ITIJT channel grid. The only way to overcome this challenge is to leverage
complex modulation techniques from
the wireless and RF microwave world,
which solved this problem at lower data
rates two decades ago. The solution is
to take advantage of the significant
dense packaging of information afforded with advanced optical modulation
schemes, reducing the necessary
transceiver bandwidth.
Gennum Corporation recently
announced the availability of the their
16GFC SFP+ complete integrated circuit (IC) solution. The solution is comprised of a clock and data recovery
(CDR) (with integrated limiting amplifier) IC, a CDR with integrated equalizer/laser
driver
IC,
and
a
transimpedance amplifier (TIA). The
new ICs represent the most comprehensive 16GFC SFP+ solution on the market, while delivering the robust
performance required by networking
and storage applications.
The new ICs and reference designs
enable development of SFP+ modules
using the same form factor and pin-out
as previous 8GFC solutions, and therefore provide a low-cost, low-power
approach that can ease migration to
16GFC data rates. Gennum also offers
8 Gb/s and 10 Gb/s CDR solutions to
customers worldwide, providing the
robust performance and added noise
immunity needed by networking and
storage applications.
The Fibre Channel specification is
standardized in the T11 Technical Committee of the International Committee
for Information Technology Standards
(INCITS), an American National Standards Institute (ANSI)-accredited standards committee. The committee is
developing the 16GFC standard, with
expected completion later this year.
The emerging 16GFC aims to double
the throughput of the 8GFC standard,
and has a defined line rate of 14.025
Gb/s. The increased data rate of the
emerging standard brings a new set of
performance challenges that must be
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NEW PRODUCTS
addressed by designers without adding
significant cost to the overall design.
The use of CDRs in SFP+ modules
ensures high reliability and a simplified
design approach.
www.gennum.com
40GBE
AND
100GBE TEST SOLUTION
Tektronix
Tektronix, Inc. has announced new
optical sampling oscilloscope modules
for the Tektronix DSA8200 Digital
Serial Analyzer Series that promise to
lower the cost of high-performance
optical transmitter development and
standards compliance. The 80C10B
and 80C10B with Option F1 (80C10B
F1) provide a complete testing solution for compliance verification of next
generation transmitter standards from
40 Gb/s to 100 Gb/s and beyond. The
company also announced the
80C25GBE module for 100 Gb/s Ethernet (100GbE) manufacturing and
compliance verification.
Driven by such demands as high-definition on-demand Internet Protocol
television (IPTV), cloud computing and
online gaming, the telecommunications
and data communications industries are
rapidly migrating to faster data rates
with the emergence of 40 Gb/s and 100
Gb/s Ethernet communications protocols. To realize this next migration up
in performance, component, module
and systems manufacturers need highly
accurate and versatile test solutions that
support all key optical and electrical
standards.
The 80C10B module provides 80+
GHz optical bandwidth and signal
fidelity for detailed characterization of
18
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40 Gb/s and beyond. With the Option
F1, users gain patented filtering technology for specific industry standards —
making the 80C10B F1 a single module.
www.tektronix.com
YAHARA FAMILY
AMCC
Applied Micro Circuits Corporation
has announced Yahara, a new series of
devices for next generation optical network physical layer solutions supporting
10-Gigabit Ethernet, Metro, and Long
Haul network applications.
The Yahara devices are designed
specifically for the highly-integrated,
low cost and low power requirements
of Multi-Service Transport, Dense
Wave Division Multiplexing (DWDM)
and Metro/Core switch router applications. The family of devices represents AMCC’s fifth generation of
integrated local area network (LAN),
wide area network (WAN), and optical transport network (OTN) silicon
solutions.
The Yahara product line builds on
the success of AMCC’s MetrON product line by extending Edge and Metro
Carrier Ethernet features into Metro
and Long Haul Optical Network applications. By providing additional modes
of 10G to OTU-2 mapping features and
incorporating a second 10G Phy into
the Yahara product line, AMCC provides telecom original equipment manufacturers (OEMs) with unmatched
levels of power, space and cost savings
for OTU-2 transponder and regenerator applications.
As carrier service providers continue their migration away from traditional SONET/SDH based services to lower
cost 10G optical services, Yahara
enables telecom OEMs to build flexible
and cost-effective platforms to map
exploding volumes of Ethernet traffic
directly onto optical transport networks. By offering three packages supporting 10G “AnyRate” protocols, the
Yahara is ideally suited for a variety of
blade applications including 10G
c1ient-line cards, 10G transponders/
muxponder cards, 10G regenerator
cards, and 40G to 100G muxponder
applications.
The Yahara product line integrates
10GbE/10G Fibre Channel (FC)/8G
FC/OC-192/STM-64 to OTU-2 mapping
services, FracN clock synthesizing circuitry, Electronic Dispersion Compensation (EDC), GFEC/Enhanced FEC,
and 10G serdes functions in a single
device. By eliminating the need for various external phys and interface bridge
devices Yahara devices enable telecom
OEMs to reduce 10G Optical Transport Unit-2 (OTU-2) transponder and
regenerator line card power and space
requirements by up to 56 percent and
81 percent, respectively.
The Yahara S10123 is designed for
10G OTU-2 c1ient-line tributary Metro
Ethernet and Switch/Router applications. Its flexible system interface supports XAUI/SFI4.P2/SFI-5s protocols
and enables the direct connection to
network processors, 10G Ethernet
switches, 10G framers and 10G MACs.
Yahara’s 10G line XFI interface
enables the direct connection to XFP
and SFP+ optic modules. This enables
telecom OEMs to realize significant
power, space and cost savings with the
elimination of external Phys. The
Yahara S10123 is packaged in a 19×19
sqmm plastic ball grid array.
www.amcc.com
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CANDIDATES ANNOUNCED FOR BOARD OF GOVERNORS
NIM K. CHEUNG, PAST PRESIDENT AND CHAIR, NOMINATIONS & ELECTIONS
Dear ComSoc Member,
In the following paragraphs you will find the position statements and biographies of an outstanding slate of candidates to manage the IEEE Communications Society. Your vote is very
important to the individual candidates and to ComSoc as a whole.
Ballots will be emailed or mailed to all ComSoc members later this month. We encourage
your careful consideration as you cast your vote for the future success of the Society.
CANDIDATES FOR VICE PRESIDENT
VICE-PRESIDENT — CONFERENCES
KHALED B. LETAIEF
There are no questions that our Society is facing major difficulties such as dropping membership and the need to engage
practitioners. The recent global financial crisis will most likely
worsen our financial situation, and it will require strong leadership to address potential deficits while sustaining membership satisfaction.
If elected Vice-President for Conferences, it will be an
honor to serve you. I have been dealing with conferences for
over 20 years as an author/reviewer for leading flagship conferences. I also had the privilege of serving in other capacities
such as Founding Editor-in-Chief of one of the most respected IEEE journals. I therefore believe that my extensive service, leadership experience, and diverse background put me in
a unique position to address the society challenges. I will do
so by:
Working hard to keep our conferences in strong financial
health while making sure that they are still affordable to all
our members
Continuing to strengthen our values to academics while intensifying and encouraging industrial participation in ComSoc
meetings, and in particular by collocating some of our conferences with related trade shows to fuel attendance of
business leaders and practitioners
Improving the content of our conferences and making sure
that they continue to be valued for rapid dissemination of
relevant information and networking
Properly supporting the volunteers and staff who create and
manage our conferences
Biography
Dr. Letaief received B.S. with Distinction, M.S., and Ph.D.
degrees from Purdue University, West Lafayette, Indiana, in
1984, 1986, and 1990, respectively. He is currently a Chair
Professor and head of the ECE Department at HKUST and
director of the Hong Kong Telecom Institute of Information
Technology. He is an IEEE Fellow, a ComSoc Distinguished
Lecturer, and the recipient of the 2007 Communications Society Publications Exemplary Service Award. He has consulted
and given invited keynote talks all over the world, and has
published over 350 technical papers and eight patents.
He has served as a volunteer in many positions, including
elected member of the IEEE ComSoc Board of Governors,
Founding Editor-in-Chief of the prestigious IEEE Transactions on Wireless Communications, Editor-in-Chief of the
IEEE Journal on Selected Areas in Communications Wireless
Series, Technical Program Co-Chair of ICCCAS ’04, General
Co-Chair of WCNC ’07, and Technical Program Co-Chair of
ICC ’08. He was Chair of the Personal Communications Technical Committee; Chair of 2008 IEEE TA/MGA Visits Pro-
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gram; Chair of IEEE Transactions on Wireless Communications Steering Committee; and a member of several IEEE
committees (e.g., Recertification, Ontology, Technical Activity
Council, Publications Board, Operating Committee, Fellow
Evaluation Committee, and Asia-Pacific Board).
STAN MOYER
One of IEEE’s current struggles is how to remain relevant
to the practicing engineer. If elected to the position of VP of
Conferences, I will use my experience to support the needs of
the practicing engineer while continuing to promote academic
engineering research that enables and feeds advances in industry. Coming from the commercial world, where I am the program manager for my company’s long-range research program,
I understand the importance of fundamental technical research
and the potential impact it can have if focused correctly.
The importance of business relevance of technical work is
becoming an increasingly predominant theme these days. I
would like to foster closer interactions between the academic
and industrial communities to identify sets of problems that
are both technically interesting and challenging, but also
address a specific business need. I would like to use my position as VP of Conferences to promote conference and workshop activities that encourage these interactions on topics of
interest to both communities.
Biography
Stan Moyer is executive director and strategic research
program manager in the Applied Research area of Telcordia,
where he has worked since 1990. Currently, he is the product
manager for a hosted service for mobile marketing and affinity messaging and mobile Web applications. In the past, he has
led research and business development activities related to
digital content services and home networking. He is also president of the OSGi™ Alliance, an industry consortium creating
specifications for the managed delivery of networked services.
He received an M.E. degree in electrical engineering from
the Stevens Institute of Technology, Hoboken, New Jersey, in
1990, a B.S. degree in engineering physics from the University
of Maine in 1987, and an M.B.A. in technology management
from the University of Phoenix in 2004.
He has been a member (2008) and corresponding member
(2007) of the IEEE TAB Finance Committee. In ComSoc he
serves as Treasurer (2006–2010); he has served as a Board of
Governors Member-at-Large (2004–2006); a Technical and
Series Editor for IEEE Communications Magazine (2001–2005,
2008–2009); a member of the IEEE Transactions on Multimedia Steering Committee (2002–2003); Chair (2001–2002) and
Secretary (1995–1997) of the Multimedia Communications
Technical Committee;Vice Chair of the Enterprise Networking Technical Committee (1996–1998); and a member of the
ComSoc Standards Board (2006–2009).
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For CCNC, he has served as Co-Chair (2008), Steering
Committee Chair (2002–2003), Steering Committee ViceChair (2005–2009), Technology Applications Panel Chair
(2007), and Technical Program Committee member (2007).
He has also served as a Steering Committee member for
IEEE ICME (2002–2005); a member of the Technical and
Steering Committees for the International Workshop on Network Appliances (2000–2003); Program Chair of the IEEE
ICC Next Generation Internet Symposium (2001–2002); and a
member of the Technical Program Committees for many
IEEE ICCs and GLOBECOMs (1994–2001).
VICE-PRESIDENT — MEMBER RELATIONS
SERGIO BENEDETTO
A large number of dedicated members actively contributing to Society activities is essential to achieve the goals of our
volunteer-driven professional organization. In the last few
years, the number of ComSoc members went down from the
peak of over 60,000 members in 2001 to below 45,000 members. In parallel, ComSoc has enhanced its flavor as a truly
global organization, which now counts more than 56 percent
of its members outside the United States. The main reason
for the decline in membership resides in the ability to access
ComSoc’s publications online without having to be a Society
member. After IEEEXplore, ComSoc lost one of its main
assets in attracting and keeping members. This poses a crucial
challenge to ComSoc in general, and to the VP for Member
Relations in particular: to be able to offer new “values” to our
members so that they will not only join but also continue
being members.
If elected, I will do my best to accelerate the development
and diversification of ComSoc-offered values to members by
trying to reach them locally by enhancing the distinguished
lecturers in Chapters and Sister Societies, and globally by
increasing the attractiveness of our journals/conferences, with
the goal of having the global composition of our Society
reflected in all instances, from the Board of Governors to Editorial Boards.
Biography
Sergio Benedetto is a professor at Politecnico di Torino.
Active for more than 30 years in the field of digital communications, he has coauthored four books and over 250 papers in
leading journals and conferences. He has received the Premio
Siemens per le Telecomunicazioni in 1973, the Premio Bianchi
of AEI in 1974, the Premio Bonavera dell'Accademia delle
Scienze di Torino in 1976, the Gold Medal Award of Siemens
Telecomunicazioni for the years 1993 and 1995, the Italgas
International Prize for Research and Technological Innovation in 1998, and the Cristoforo Colombo International
Award for Communications in 2006.
He has been Chair of the Communication Theory Technical Committee, was instrumental in organizing many IEEE
conferences, was TP Chair of the Communication Theory
Symposium at ICC 2000 and 2006, and General Chair of the
Communication Theory Workshop in 2004. An IEEE Fellow,
he has been Area Editor for IEEE Transactions on Communications and a Distinguished Lecturer of ComSoc. He was Vice
President of Technical Activities of the IEEE Communications
Society in 2006–2007, and is Vice-President for Publications in
2008–2009. He is member of the Turin Academy of Science.
VIJAY BHARGAVA
As Past Vice President of IEEE, I learned to facilitate volunteer activities for regional entities and assisted IEEE Presidents with Sister Society relations in India, Japan, and Russia.
This has prepared me well for ComSoc activities and programs related to members, Chapters, member development,
relations with professional societies worldwide, and fostering a
strong international Society presence. Objectives of such activities should be to strengthen our publications, conferences,
standards, and student activities. We must continue to improve
quality, timeliness, relevance, and ease of online access of our
services. Cross-reference links to other publishers and the creation of a job bank will make ComSoc more attractive to its
members.
Our technologies are becoming increasingly interdisciplinary. ComSoc must introduce products that address these
interdisciplinary needs and give practical information to our
members. Identification and promotion of emerging technologies is a must to position ComSoc as a dominant player.
Viable financial health is important, but it should not come by
charging exorbitant conference registration fees and mandatory page charges.
I am a recipient of the IEEE Haraden Pratt Award for
meritorious service to the Institute, particularly in regional
and section activities, and for efforts to improve relationships
with technical and professional organizations worldwide. This
citation reflects the approach I favor. It will be a pleasure to
be of service to you.
Biography
Vijay Bhargava is a professor at the University of British
Columbia, Vancouver, Canada. As a distinguished speaker for
IEEE entities, he has lectured in 66 countries and has rudimentary knowledge of 15 languages. He received his Ph.D.
from Queen’s University, Canada. He has held visiting
appointments at Ecole Polytechnique, NTT Research Lab,
and Hong Kong University of Science and Technology. He is
a co-author of Digital Communications by Satellite (Wiley,
1981), which was translated into Chinese and Japanese. He is
a co-editor of Reed-Solomon Codes and Their Applications
(IEEE Press, 1994) and Cognitive Wireless Communication
Networks (Springer, 2007).
He has served on the Boards of Governors of the IEEE
Information Theory and IEEE Communications Societies. He
has held important positions in these societies, and organized
and chaired conferences such as ISIT ’95, ICC ’99, and VTC
’02 Fall. He is past Editor of IEEE Transactions on Communications and a past President of the IEEE Information Theory Society. He chairs the IEEE Teaching Award Committee
and serves on an IEEE ad hoc committee with a focus on
India. He played a major role in the creation of WCNC and
IEEE Transactions on Wireless Communications, for which he
currently serves as the Editor-in-Chief.
VICE-PRESIDENT — PUBLICATIONS
LEN CIMINI
The collection of ComSoc publications, including the journals, magazines, and educational products, is a shining star of
the Society. However, to maintain this standard and continue
to play an influential role in the rapidly changing world of
communications, several challenges must be addressed. If
elected, I will:
•Strive to make ComSoc publications more timely, relevant,
and accessible, while maintaining the high quality expected
by our members. To achieve this goal, we must make better
use of our Web-based capabilities to reduce the publication
time and increase the availability of our products to a
broader audience.
•Meet the increasingly divergent needs of both academia and
industry. This can be accomplished by expanding our cur-
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rent initiatives in application-based publications and providing an outlet for new emerging, often interdisciplinary,
technical areas.
•Develop more, and easier to access, online content. This
should include offerings such as moderated debates on
important topics to the ComSoc community, online expert
centers, and special interest discussion groups.
I believe that my background in both industry and
academia, combined with my broad experience in ComSoc
service activities, especially in publications, puts me in a
unique position to effectively initiate these activities and successfully bring them to fruition.
Biography
Len Cimini received his B.S., M.S., and Ph.D. in electrical
engineering from the University of Pennsylvania in 1978,
1979, and 1982, respectively. He worked at AT&T, first in
Bell Labs and then AT&T Labs, for 20 years, where his
research concentrated on lightwave and wireless communications.
He has been very active within ComSoc for more than 20
years. In the publications area, he has been an editor and area
editor for the IEEE Transactions on Communications, is currently a Senior Editor for the IEEE Journal on Selected Areas
in Communications, and is the founding Editor-in-Chief of the
IEEE JSAC Wireless Communications Series. Currently, he is
the Director of Online Content. Among his past activities, he
served twice as an elected member of the Board of Governors, and was Chair of the Emerging Technologies Committee.
He was elected IEEE Fellow in 2000 for contributions to
the theory and practice of high-speed wireless communications. In 2007 he was given the James R. Evans Avant Garde
Award from the IEEE Vehicular Technology Society for his
pioneering work on OFDM for wireless communications. He
has been a professor at the University of Delaware since 2002.
He has published more than 100 papers and has 16 issued
patents.
VICE-PRESIDENT — TECHNICAL ACTIVITIES
ALEXANDER GELMAN
The IEEE Communications Society operates now in a
challenging global environment. If elected, I will work to
improve and enhance ComSoc publications and adapt them to
the changing needs.
I believe that the following issues must be addressed first:
publication timeliness, reviewing quality and fairness, further
increasing practical and industry-related content in our magazines, keeping the leading role of our archival journals, as well
as targeting new areas and technologies that may lead to
launching new publications. We will face challenges related to
open access and distribution of various types of content to
consumers via the Internet. I believe that my experiences in
the publications area and ComSoc activities will help me to
effectively lead the publications affairs of the Society.
ComSoc Technical Activities Council includes Technical
Committees, Standards, Education, Distinguished Lecture
Selection pool, Fellow Evaluation, Emerging Technologies,
and Communications History.
ComSoc’s technical scope evolves in order to keep up with
industry dynamics and to serve emerging industry segments. I
helped ComSoc to claim turf in consumer communications
and networking, BPL, cognitive radio, peer-to-peer networks,
and other technical areas. If elected, I will work on exploring
new technical horizons, customizing ComSoc’s value proposition to various industry segments, and new programs for
industry practitioners.
Staying relevant to industry is critical for ComSoc. We
must leverage our expertise in producing technology roadmaps
to position ComSoc as a beacon for innovation and source of
technical problem statements, and also in fostering global
standards development. We are in a strong position to facilitate industry-academia partnerships. If elected, I will promote
symposia for industrial and academic researchers on hot topics, on R&D funding activities by industry, governments, and
venture capital, and on global research and standardization
projects.
Research results that are contributed to standards produce
significant impact. However, engaging researchers in standardization remains a challenge. In partnership with IEEE-SA I
will work on incentives for academic and industrial researchers
to work on IEEE standards: awards, promotion to fellow
grade, and visible attribution of credit to researchers and
practitioners who contribute to standards.
Biography
Andrzej Jajszczyk is a professor at AGH University of Science and Technology, Krakow, Poland. He received his M.S.,
Ph.D., and Dr Hab. degrees from Poznan University of Technology in 1974, 1979, and 1986, respectively. He spent a year
at the University of Adelaide in Australia and two years at
Queen’s University, Kingston, Ontario, Canada, as a visiting
scientist. He is the author or co-author of seven books and
over 240 papers, as well as 19 patents in the areas of telecommunications switching, high-speed networking, and network
management. He has been a consultant to industry, telecommunications operators, and government agencies.
Biography
Alexander D. Gelman received his M.E. and Ph.D. in
electrical engineering from City University of New York.
Presently he is CTO of NETovations, a networking research
consulting group. During 1998–2007 he was the chief scientist of Panasonic Princeton Laboratory, managing research
programs in consumer communications and networking.
During 1984–1998 he worked at Bellcore, most recently as
director of Internet Access Architectures Research group.
He has worked in different areas of communications and
networking, including spread spectrum, DSL, IPTV, DTV,
UWB, information security, and networked multimedia. He
ANDRZEJ JAJSZCZYK
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He was the founding editor of the IEEE Global Communications Newsletter, an editor for IEEE Transactions on Communications, and Editor-in-Chief of IEEE Communications
Magazine. At the end of his three-year term, IEEE Communications Magazine reached the top position of the impact factor
list among all publications in the telecommunications area,
the first and only time in the magazine’s history. During his
term the advertising revenue increased by 80 percent.
In 2004–2005 he was Director of Magazines of IEEE
Communications Society, and in 2006–2007 he was Director
of the Europe, Africa, and Middle East Region of ComSoc.
Since January 2008 he serves as Vice-President — Technical
Activities. He organized the first IEEE Workshop on IP
Operations & Management (IPOM) and the first IEEE BSS
that later became the IEEE High Performance Switching
and Routing Workshop (HPSR). In 2008 he was the recipient of the IEEE Communications Society Joseph LoCicero
Award for Exemplary Service to Publications. He is VicePresident of the Board of the Kyoto-Krakow Foundation,
fostering cultural and scientific relations between Asia and
Poland.
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has over 100 publications and holds several patents, including some of the earliest DSL system patents, such as an
xDSL-based access router.
He has served on several IEEE and ComSoc committees,
and worked on publications and conferences; he served on
inaugural steering committees for IEEE Transactions on Multimedia and ICME. He founded CCNC, initiated BPL and
cognitive radio standardization, and chaired the Multimedia
Communications Technical Committee. He served three
terms as ComSoc Vice President, and served on the IEEE-SA
Board of Governors. Currently, he is ComSoc’s Director of
Standards and a member of IEEE-SA Standards Board. He is
the 2006 winner of IEEE ComSoc’s Donald W. McLellan
Meritorious Service Award.
MARK KAROL
Technical Activities is the foundation for many ComSoc
products and member services. Twenty-three years ago I
began my ComSoc volunteer work within the Technical Committee on Computer Communications. It led to many years of
fulfilling work, opportunities, professional development, and
friendships. We should continue to expand opportunities and
encourage members (of all backgrounds and interests) to participate in the many activities of the Society.
As the VP — Technical Activities, I would strive to further
improve the high quality standards and value of ComSoc technical activities. I would help identify and encourage ComSoc’s
involvement in emerging technologies of interest to our members. We should also provide new educational opportunities,
stimulate and guide new standards activities, and consider certification in various technological fields.
Within ComSoc, the term “technical activities” encompasses a wide range of topics: education, standards, technical committees, awards, Distinguished Lecturers, IEEE Fellow
evaluation, and emerging technologies. I have extensive experience in all these areas, having served on many of the associated ComSoc committees and boards. In addition, I served on
the IEEE Technical Activities Board, IEEE Educational
Activities Board, and IEEE Fellow Evaluation Committee. I
believe that my industrial research career, and my extensive
ComSoc and IEEE experience have prepared me well to
effectively serve as your next ComSoc VP — Technical Activities. It would be an honor to have your vote and to be able to
serve you.
Biography
Mark Karol received a B.S. in mathematics and a B.S.E.E.
from Case Western Reserve University, and a Ph.D. in electrical engineering and computer science from Princeton University. From 1985 until 2000 he was a member of the Research
Communications Sciences Division at Bell Laboratories. From
2000 until 2008 he was a research scientist with Avaya. He was
also an ECE adjunct professor at Polytechnic University,
Brooklyn. Currently, he is a senior scientist with Telcordia
Technologies.
He has held many leadership positions in technical committees, publications, and conference activities of the IEEE.
He also served two years on the IEEE Board of Directors. He
was the first Associate Editor on Networks/Switching for the
Journal of Lightwave Technology, General Chair of ICC ’02,
and General Chair of IEEE INFOCOM ’94. He has also
served as ComSoc CIO, ComSoc Director of Magazines, and
is currently ComSoc VP — Conferences.
He received the Society’s Donald W. McLellan Meritorious Service Award (2005) and the ComSoc Best Tutorial
Paper Award (1997). He has over 100 technical publications
and has been granted 32 U.S. patents. He is a Fellow of the
IEEE.
CANDIDATES FOR MEMBER-AT-LARGE
IAN F. AKYILDIZ
My ultimate objective is to enhance the value of the IEEE
Communications Society to its members by ensuring high
standards of quality, increasing Society membership, and promoting industry collaboration.
Maintaining the high technical quality of the transaction
journals and conferences is one of my main concerns. The
publication time of papers in the transactions is enormously
long, which I shall strive to reduce. I believe that there exists a
disparity in quality levels of the ComSoc conferences — some
are of high quality, while others greatly lower the bar regarding paper acceptance. For this, I will work on ensuring a uniform standard for accepted papers.
I will try to increase membership of the Society through
avenues such as organizing workshops and courses in countries worldwide. I also wish to improve cooperation between
the research activities of Sister Societies. Finally, I will work
toward broadening standards activities, thereby enhancing our
relevance to the industry and creating a mutually supportive
relationship.
If elected, I will use all my energy and time to increase the
benefits of the IEEE Communications Society to our members.
Biography
Ian F. Akyildiz is the Ken Byers Distinguished Chair Professor with the School of Electrical and Computer Engineering, Georgia Institute of Technology, director of the
Broadband Wireless Networking Laboratory, and chair of the
Telecommunications Group.
Dr. Akyildiz is an IEEE Fellow (1996) and an ACM Fellow (1997). He has been the general and program chair for
several IEEE and ACM conferences, including INFOCOM
’98 and ICC ’03. He has served as an IEEE Distinguished
Lecturer for IEEE ComSoc since 2008.
Dr. Akyildiz has received numerous IEEE and ACM
award,s including the 1997 IEEE Leonard G. Abraham Prize
(IEEE Communications Society), 2002 IEEE Harry M.
Goode Memorial Award (IEEE Computer Society), 2003 Best
Tutorial Paper Award (IEEE Communications Society), 2003
ACM SIGMOBILE Outstanding Contribution Award, and
the 2005 Georgia Tech Distinguished Faculty Achievement
Award.
RAOUF BOUTABA
ComSoc should play a greater role in addressing the professional needs of members, academia, and industry worldwide. If elected I will focus on:
•Ensuring that ComSoc continues disseminating the highestquality technical information via conferences, journal/magazine publications, and customized access to online content,
“live” tutorials, Web-based seminars, and online communities
•Increasing industry support by facilitating communications
standards development and targeted publications
•Strengthening ComSoc globalization by attracting profes-
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sionals from developing countries and increasing cooperation with local technical societies worldwide
•Increasing participation of students and women
•Attracting new members through better support to local
chapters, expanding the Society’s interdisciplinary activities,
and including emerging technical areas such as security,
operations and management, converged wireless, optical
and Internet technologies, systems, applications, and services
My background in industry research and academia combined with my ComSoc experience in technical activities and
membership services will enable me to better solicit members’
opinions and serve our Society.
Biography
Raouf Boutaba is a professor of computer science at the
University of Waterloo, Canada. He has published over 300
papers in refereed journals and conferences, and has two U.S.
patents. He is the recipient of the Premier’s Research Excellence Award, several Best Paper Awards, as well as other
recognitions from academia and industry. He received IEEE
ComSoc’s Harold Sobol Award for Exemplary Service to
Meetings & Conferences in 2007 and IEEE ComSoc’s Fred
W. Ellersick Prize in 2008.
He is active within ComSoc in many capacities: Chair of
the Kitchener-Waterloo Chapter; Chair of the Information
Infrastructure Technical Committee; founding Chair of the
Autonomic Communications Subcommittee; voting member
of Meetings/Conferences Board; Director of Conference Publications; and member of the Education Board. Previously, he
was Director of Related Societies, the first Director of Standards, Vice Chair of the Information Infrastructure Technical
Committee, and a member of the Online Content Board. He
is founding Editor-in-Chief of IEEE Transactions on Network
and Service Management and an editor for other journals. He
chairs the IM/NOMS steering committee, has organized several conferences, and is a Distinguished Lecturer.
STEFANO BREGNI
IEEE Communications Society is the global home where
we members find information, network with other experts,
and publish our best research work. Our scientific and professional activities depend largely on the quality of ComSoc
products and services.
I have contributed significantly to this aim in ComSoc. In
GITC, I worked to define the standard paper review procedure. As Symposium Chair or TPC member, I always strove to
ensure that all papers were peer-reviewed accurately by independent experts. As Distinguished Lecturer, in five years I
had eight tours, visited 13 countries and 28 Chapters worldwide, and gave 30+ lectures to student, academic, and professional ComSoc members.
If elected, I commit to:
Further enhance ComSoc globalization
Facilitate participation of students, Chapters, and members of
all Regions in global initiatives, also addressing economical
barriers
Enrich the portfolio of free and low-cost online education services for members
Guarantee timely, strict, and fair peer review of papers in
conferences and publications
Biography
Stefano Bregni is an associate professor at Politecnico di
Milano, Italy. He graduated in electronics engineering from
Politecnico. He worked in industry with SIRTI (1991–1993)
and CEFRIEL (1994–1999). He joined Politecnico in 1999.
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He is an IEEE Senior Member (1999). Since 2004 he has
been a ComSoc Distinguished Lecturer. In the Communications Society he is Director of Education (2008-09), Chair of
the Transmission, Access & Optical Systems Technical Committee (TAOS) (2008–2009; Secretary/Vice-Chair since 2002),
and a voting member of the GLOBECOM/ICC Technical
Content (GITC) Committee (2006–2009). He is Symposia
Chair of GLOBECOM ’09 and has previously co-chaired six
single ICC/GLOBECOM symposia. He is Editor of the ComSoc Global Communications Newsletter. He has given tutorials
at four ICC/GLOBECOMs. He has contributed to ETSI and
ITU-T standards on network synchronization. He is the
author of 70+ refereed papers and the book Synchronization
of Digital Telecommunications Networks (Wiley, 2002).
VINCENT CHAN
I feel that industry and academia in the Communication
Society are drifting apart in their research interests and areas
of focus. The Society should promote better dialog between
the two groups at its major conferences and through special
ad hoc committees to explore new research and development
horizons. It is with this goal that I agreed to serve as the Editor-in-Chief of the IEEE Optical Communications & Networking Series, JSAC Part II, now transitioning to a new
IEEE/OSA journal. My prior and continuing advisory experience for U.S. and non-U.S. governments in R&D will be helpful in promoting new research agendas and creating new
funding sources for worthy communications research.
Biography
Vincent W. S. Chan, the Joan and Irwin Jacobs Professor
of EECS, MIT, received his B.S., M.S., EE (1971 and 1972),
and Ph.D. (1974) degrees in electrical engineering from MIT.
From 1974 to 1977 he was an assistant professor of electrical
engineering at Cornell University. He joined MIT Lincoln
Laboratory in 1977 and was head of the Communications and
Information Technology Division until becoming director of
the Laboratory for Information and Decision Systems
(1999–2007).
In July 1983 he initiated the Laser Intersatellite Transmission Experiment Program, and in 1997 the follow-on GeoLITE Program. In 1989 he formed the All-Optical-Network
Consortium among MIT, AT&T, and DEC. He also formed
and served as PI of the Next Generation Internet Consortium,
ONRAMP among AT&T, Cabletron, MIT, Nortel, and JDS,
and a Satellite Networking Research Consortium formed
between MIT, Motorola, Teledesic, and Globalstar.
This year he helped form (and is currently a member of)
the Claude E. Shannon Communication & Network Group at
the Research Laboratory of Electronics, MIT. He is a Member of the Corporation of Draper Laboratory, Eta-Kappa-Nu,
Tau-Beta-Pi, and Sigma-Xi, and a Fellow of the IEEE and the
Optical Society of America.
TARIQ DURRANI
I hope to contribute to the following ComSoc activities:
•Effective international conferences — Having organized several major conferences for the IEEE as General/Executive
Chair (ICC ’07,1400 participants, IEMC ’03, 350 participants, EUA ’05, 650 participants, ICASSP ’89, 1650 participants), stimulating greater participation from industry and
industry relevant events well demonstrated at ICC ’07.
•Timely and rapid publications — Having served on IEEE
TAB as Chair of the Periodicals Council, I have the experience and understanding to minimize time delays, and maintain and improve quality.
•Member services — Improved provision of localized and
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global opportunities through more effective Chapters linking industry to academia; and professional development
and educational opportunities for members through collaboration with EAB.
Biography
Tariq Durrani obtained his M.S.c and Ph.D. from
Southampton University, United Kingdom, and is a professor in electronic and electrical engineering at the University
of Strathclyde, Glasgow, United Kingdom since 1982. He
was department head (1990–1994), and university deputy
principal (provost equivalent) from 2000 to 2006. He has
supervised ~ 40 Ph.D.s, and held visiting/external appointments at Princeton, University of Southern California, and
Hong Kong. He has authored/coauthored over 330 papers
and six books.
He was Executive Chair of the hugely successful IEEE
International Conference on Communications (ICC ’07),
Glasgow, Scotland. He was President of the IEEE Signal Processing Society (1994–1995); President of the IEEE Engineering Management Society (2006–2007); a member of the IEEE
Technical Activities Board (TAB) Management Committee
(1996–1997); Chair of the IEEE TAB Periodicals Review
Committee (1998–1999); and IEEE Periodicals Council
(1996–1997) with oversight responsibility for all IEEE transactions, journals, magazines, and newsletters.
He was a member of the IEEE Edison Medal Committee
(1995–1997),
Jack
Kilby
Medal
Committee
(1996–1999;2007–08), IEEE Medal of Honor Committee
(2005–2008), and IEEE Awards Board (2006–2007). He was
also a member of the IEEE Spectrum Editorial Board
(2002–2004), Vice Chair of the IEEE Publications Board
(1996–1997), Chair of the IEEE Region 8 Conference Committee (2001–2002), Vice Chair — Technical Activities, IEEE
Region 8 (2003–2004), member of the IEEE Education Activities Board (EAB) (2001–2005), Chair of the EAB Awards &
Recognition Committee (2003–2005), and member of the
IEEE Conferences Committee (2007–2009).
STEVE GORSHE
With over 26 years in industry, and having completed my
Ph.D. in parallel, I understand and appreciate the needs of
both industry and academia. It is critical for ComSoc, however, to provide continuing value to engineers working in industry. Students also benefit from an industry focus, by giving
them perspective on potential areas for future employment or
topics that are important to industry for additional research. I
am currently involved in such efforts to balance the focus of
the ComSoc magazines. Publishing content relevant to industry is critical for retaining student members when they move
into industry and for attracting new members.
Other efforts I will enthusiastically support include:
•Developing certificate programs like the Wireless Communication Engineering Technologies Certificate
•Offering conference sessions and workshops that promote
effective interaction to identify solutions to industry problems
•Increasing ComSoc involvement in important standards
areas not adequately addressed by other bodies
Biography
Steven Scott Gorshe received his B.S.E.E. from the University of Idaho (1979)m and M.S.E.E. (1982) and Ph.D.
(2002) from Oregon State University. His work has included a
wide variety of hardware design, system architecture, and
applied research for GTE, NEC America, and PMC-Sierra,
where he is a principal engineer. He has been active in six
telecommunications and datacom standards bodies, including
ITU-T, with about 300 contributions, multiple technical editorships, and receiving two prestigious awards. He was elected
an IEEE Fellow (2007) for invention and standardization of
elements of optical transmission systems. He has 30 patents
issued or pending, over 24 published papers, and is co-author
of a book and two chapters.
His wide-ranging IEEE ComSoc activities include Director
of Magazines; IEEE Communications Magazine Associate Editor-in-Chief, Broadband Access Series Editor, and four-time
Guest Editor; Transmission, Access, and Optical Systems
(TAOS) Technical Committee Chair; Oregon Chapter Chair;
and a member of the Awards Committee and Strategic Planning Committee.
JAMES HONG
If elected as a member at large, I will work closely with the
President, VPs, Directors, Members-at-Large, and ComSoc
staff to plan, support, and execute actions that will:
•Increase the value of membership for both academia and
industry
•Support true globalization of membership and activities
•Increase the excellence and timeliness of journal and conference publications and online content
•Start new initiatives (e.g., technical committees, journals,
conferences) related to interdisciplinary technologies
•Make the ComSoc portal and digital library the primary
sources of members’ educational, career, and business success
•Expand opportunities and encourage more participation by
students, who are the future of our Society
Biography
James Won-Ki Hong received B.S. and M.S. degrees from
the University of Western Ontario in 1983 and 1985, respectively, and a Ph.D. degree from the University of Waterloo in
1991. He is currently a full professor, dean of the Graduate
School for Information Technology, and director of Information Research Laboratories at Pohang University of Science
& Technology. He has been an active volunteer for various
ComSoc committees and ComSoc sponsored symposia such
as NOMS, IM, DSOM, and APNOMS. He has served as
Technical Chair, Vice Chair, and Chair (2005–present) of
ComSoc’s Committee on Network Operations & Management (CNOM). He has also served as Director of Online
Content for ComSoc (2004–2005), NOMS/IM Steering Committee Member (2003–present), and Technical Co-Chair of
NOMS 2000 and APNOMS ’99. He was Finance Chair for
IM 2005 and 2009 and NOMS 2004 and 2006. He was General Chair for APNOMS 2006 and 2008. He is the Conference
Operations Chair for GLOBECOM ’09. He is also serving as
General Co-Chair for NOMS ’10. He has been an editor of
IEEE TNSM, JNSM, IJNM, and JTM. He is a Senior Member
of IEEE.
ABBAS JAMALIPOUR
The Communications Society has a great responsibility to
the professional community, both in industry and academia, to
maintain the highest-quality publications in the field. As a
member of the Board of Governors, I will commit myself to
strengthening the peer review process for journals and conferences organized by the Society. Our members would like to
have access to the state-of-the art literature in the field, and
they see the Society as a leading entity in offering such opportunity. I would like to push the Society for better, faster, and
fairer evaluation during the review process, and simplify
access to publications to those in need, including engineers
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and students. I want to offer my extensive experience as an
editor and conference technical committee member to help
address these issues.
I will also commit to increasing opportunities for students,
who are the future of our Society, to participate in conferences and other technical events, and improve the Society’s
education and training activities.
Biography
Abbas Jamalipour received his Ph.D. from Nagoya University, Japan, in 1996. He has held positions at Nagoya University and Tohoku University, and in the telecommunications
industry. He is now a professor at Sydney University, Australia, leading the Wireless Networking Group. He is a Fellow
of IEEE and IEAust, ComSoc Distinguished Lecturer, Editorin-Chief of IEEE Wireless Communications, and Technical
Editor for several journals. He has authored/co-authored four
books, nine chapters, and over 200 journal/conference papers,
and holds two patents.
Within ComSoc, he has been the Chair of Satellite &
Space Communications (2004–06); Vice Chair of Communications Switching & Routing; and Chair of Chapters Coordination Committee, Asia/Pacific Board. He is a Technical Editor
of IEEE Communications Magazine and a member of the
Education Board, GITC, and IEEE WCNC Steering Committee. He was a Vice-Chair of WCNC 2003–2006, Chair of
IEEE GLOBECOM ’05 (Wireless Communications), and
Symposium Co-Chair at ICC 2005–2008 and IEEE GLOBECOM 2006-2008, among many others.
PASCAL LORENZ
IEEE Communication Society plays an important role in
the organization of conferences and the publication of journal
papers. ComSoc should continue to provide benefits to its
members, who should be involved in ComSoc decisions and
management. If elected, I will focus my actions on attracting
new members and promoting student branches. I will also
enhance ComSoc technical activities, and increase the synergy
between sister societies, and the academic and industrial
worlds through the development of new working groups and
standardization projects. I will also work to diversify the services offered by our Society through the diffusion of technical
information, and development of online tools for conferences
and digital libraries.
Biography
Pascal Lorenz received his M.Sc. (1990) and Ph.D. (1994)
from the University of Nancy, France. Between 1990 and
1995 he was a research engineer at WorldFIP Europe and
Alcatel-Alsthom. He has been a professor at the University
of Haute-Alsace, France, since 1995. He is the author/coauthor of three books, two patents, and 190 international
publications in journals and conferences. He has been very
active within ComSoc: he was a Technical Editor on the
IEEE Communications Magazine Editorial Board
(2000–2006), and is the current Chair of the Vertical Issues
in Communication Systems Technical Committee Cluster,
Chair of the Communications Systems Integration & Modelling Technical Committee, and Vice Chair of the Communications Software Technical Committee. He was Co-Program
Chair of ICC ’04, and Symposium Co-Chair at GLOBECOM
2007–2009 and ICC 2008 and 2009. He has served as CoGuest Editor for special issues of IEEE Communications
Magazine, IEEE Network, and IEEE Wireless Communications. He is a Senior Member of the IEEE, a member of
many international program committees, and has organized
many conferences.
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IWAO SASASE
I believe that the main roles of ComSoc’s publications and
conferences are to fulfill various needs for members in both
industry and academia by providing access to high-quality
technical information, opportunities to discuss state-of-the-art
communication technologies from various aspects, as well as
establishing and keeping human networks of professionals
throughout the world. For ComSoc’s continuing growth and
globalization, I would like to provide more opportunities for
active participation and devise new value incentives, especially
for students and industrial members. Another objective is to
improve cooperation with Sister Societies and strengthen local
Chapters around the world to have more opportunities for
disseminating novel ideas from various communications
research communities.
Biography
Iwao Sasase received B.E., M.E., and Ph.D. degrees in
electrical engineering from Keio University, Yokohama,
Japan, in 1979, 1981, and 1984, respectively. He is now a professor and chairman of the Department of Information and
Computer Science at Keio University, Yokohama, Japan. His
research interests include broadband mobile and wireless
communications and photonic networks. He has co-authored
more than 245 journal papers and 360 international conference papers. He has been very active in IEEE ComSoc activities. He served as IEEE ComSoc Asia Pacific Regional
Director during 2004–2005, chaired the Satellite & Space
Communications Technical Committee during 2000–2002, and
was Chair of the Satellite Communication Symposium at ICC
’02. He also served as Vice President of the IEICE Communications Society during 2004–2006, Chair of the IEICE Network System Technical Group during 2004–2006, and Chair of
the IEICE Communication System Technical Group during
2002–2004. He is a Senior Member of IEEE and a Fellow of
the IEICE.
MANSOOR SHAFI
To ensure its continuing success, ComSoc has expressed a
desire to increase its membership. To this end I have three
major goals to pursue if elected:
Make ComSoc activities more appealing to the practicing
engineer by adding focus on real world issues through our
publications, conferences, surveys, and Web tutorials
Further broaden ComSoc membership around the world,
especially to professionals from developing countries by
encouraging local Chapters, publishing special issues of
IEEE Communications Magazine giving exposure to communications in developing countries, and pursuing avenues
for travel assistance for authors whose papers are accepted
at ComSoc-sponsored conferences
Focus our publications on interdisciplinary areas such as
fixed/mobile, broadband/convergence, and quality of service
Biography
Mansoor Shafi received his Ph.D. in electrical engineering
from the University of Auckland, New Zealand, in 1979. He is
employed with Telecom NZ as principal advisor on wireless
systems. He is also an adjunct professor at Canterbury and
Victoria Universities. He is a contributor to ITU-R standards
meetings for mobile systems.
He has published widely in IEEE journals and conferences.
He was a co-guest editor of JSAC special issues on MIMO; his
April 2003 JSAC paper on MIMO won the IEEE ComSoc
Best Tutorial Paper award in 2004. He is a co-guest editor of
a forthcoming IEEE Proceedings special issue on cognitive
radio.
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He is a founding member of the IEEE NZ Central Section. He is an editor of the IEEE Transactions on Wireless
Communications, was a Co-Chair of the ICC ’05 Wireless
Communications Symposium, and has held Technical Program Committee roles in ICC and GLOBECOM.
He is an IEEE Fellow, has served on the ComSoc Fellow
Evaluation Committee, and is a member of the IEEE Fellow
Awards Committee.
MEHMET ULEMA
Having worked in industry in technical and management
positions for more than 20 years, and now in academia for
about seven years, I believe I have gained considerable experience that can help ComSoc become an effective organization
that can rapidly respond to the needs of its members around
the world, from both academia and industry. I will work with
the Board of Governors to establish ways of getting members
more and more involved in the ComSoc decision making processes. This is the only way we can “shape up” ComSoc in the
directions we want: toward more attractive publications, conferences, and educational products. I will push ComSoc to do
a better job in supporting regional chapters. With your vote
and your help, we can make ComSoc an even stronger global
and dynamic Society to provide more value to its most valued
constituents: you.
Biography
Mehmet Ulema is a professor at Manhattan College, New
York. Previously, he held management and technical positions
at Daewoo, Bellcore, Bell Labs, and Hazeltine. He has served
as the Chair of the Information Infrastructure and Radio
Communications Technical Committees. Currently, he is serving as Technical Program Chair for GLOBECOM ’09. More
recently, he served as General Co-Chair for NOMS ’08, and as
Program Chair for a number of conferences including ICC ’06,
CCNC ’04, NOMS ’02, and ISCC 2000. He has served on several ComSoc committees including GITC, Online Content
Board, and Meeting & Conferences Board. Currently he is on
the editorial board of IEEE Transactions on Network & Services
Management, the Wireless Network Journal, and the Journal of
System & Network Management. He received his M.S. and
Ph.D. degrees from Polytechnic University, Brooklyn, New
York, and his B.S. degree from Istanbul Technical University.
RICARDO VEIGA
We are proud of being ComSoc members, and we should
continue to be. Also, we must attract many other communications engineers in industry and academia worldwide to become
ComSoc members. The technical quality of our publications
and conferences should be maintained, and other high quality
services should be increased and introduced.
If elected I will focus on:
•Promoting professional certification programs, standards
activities, and virtual communities
•Helping more members become volunteers within ComSoc
local Chapters, Technical Committees, and Sister Societies
•Ensuring that ComSoc continues to be recognized as the
leader in disseminating the highest-quality technical information to both academics and practicing engineers
•Producing low-cost (or even free) continuing educational
programs, through customized access to online content such
as webinars and tutorials
•Taking care of the special needs of those members in different areas of their countries all over the world
Biography
Ricardo Veiga graduated from University of Buenos Aires
(UBA) as an electronics engineer (six-year degree program).
He did postgraduate studies in automatic control (Japan),
and marketing at UADE University. He is currently a professor at UBA, teaching graduate and postgraduate courses. He
has been involved in research since 1980, has presented
papers at national and international conferences, and supervised graduate students. He has also worked in industry for
many years.
He is now leading the Training Committee for ComSoc’s
Wireless Certification Program WCET. He was a member of
ComSoc’s Board of Governors as Regional Director for Latin
America (2004–2005), increasing by 17 percent the number of
Chapters (66 percent of the Sections), and the number of Student Branch Chapters by 100 percent (38 percent of the total
worldwide). As Chair of the Argentina ComSoc Chapter, he
received the Chapter Achievement Award in 2000. He
received the IEEE RAB Achievement Award and IEEE
Third Millennium Medal, among others.
SARAH KATE WILSON
As someone who has worked in both academia and industry, I believe that ComSoc should serve both the practicing
and the academic engineer. This belief leads to the following
goals:
•Encouraging ComSoc conferences and publications to
include materials that address current, relevant standards as
well as emerging topics
•Increasing turn-around time in our publications cycle while
maintaining a quality review process to ensure the timely
publication of recent advances
•Encouraging and appreciating our hard-working volunteers
who keep the ComSoc journals and conference system
working
Biography
Sarah Kate Wilson received her A.B. in mathematics
from Bryn Mawr College in 1979, and her M.S. and Ph.D. in
electrical engineering from Stanford University in 1987 and
1994, respectively. She has worked in both academia and
industry as a professor and as a research and development
engineer. Her academic experience includes positions in
Sweden as well as the United States. Her current research
interests are in OFDM, wireless optical communications,
and scheduling.
She is currently an assistant professor in the Department
of Electrical Engineering at Santa Clara University. She has
served as Co-Chair for the Signal Processing Symposium of
ChinaCom 2008, Vice-Chair of the Communications Theory
Symposium for GLOBECOM ’05, and on the Technical Program Committees for VTC, GLOBECOM, ISSTA, ICC, and
WCNC. She is also the founder and organizer of the Santa
Clara OFDM Workshop. She has served as an Associate
Editor for IEEE Transactions on Wireless Communications,
IEEE Communications Letters, IEEE Transactions on Communications, and the Journal of Communications & Networks.
She is currently Editor-in-Chief of IEEE Communications
Letters
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Global
Newsletter
May 2009
Distinguished Lecturer Tour in Latin America — October 2008
By Stefano Bregni, Italy
The Distinguished Lecturer Program is one of the best initiatives of the IEEE Communications Society. It brings distinguished
experts to give lectures at Chapters on all continents. It boosts
ComSoc globalization by giving equal opportunities to all Chapters worldwide, since it allows students and professionals to attend
open lectures given by world renowned experts in their city. It is a
honor and a pleasure to serve as a Distinguished Lecturer.
This was my fifth Distinguished Lecturer Tour (DLT) in
Latin America. In the five years I served as a ComSoc Distinguished Lecturer, I visited 17 Chapters in 10 different countries
of Latin America, some of them repeatedly. I appreciated the
activity and efficient organization of all those chapters, especially the Student Branches, the outstanding commitment and kindness of IEEE volunteers, and — last but not least — the
extraordinary beauty of all these places. For this 2008 DLT, a
special thank is due to Nelson Fonseca (LA Region Director),
the Chapter Chairs, and all the other enthusiastic professors and
students for their joint organization effort. Muchisimas gracias a
mis amigos y amigas Peruanos, Bolivianos y Colombianos!
Summary of Lectures
My 2008 DLT was one of the longest I ever went on: I visited
Lima, Cuzco, La Paz, Medellin, and Bogota from 13 to 27 October 2008. In 14 days eight lectures were given, four days were fully
taken by traveling, with only two days left free for sightseeing.
Lectures entitled “Synchronization of Telecommunications
Networks,” “Synchronization of Next-Generation Networks,”
and “Introduction to SDH Transmission Systems” were given at:
1, 2) Lima, Peru, Universidad Nacional de Ingegneria (UNI),
CTIC, 14 October (two lectures)
3) Cuzco, Peru, ANDESCON2008 Keynote Lecture, 16 October
4) La Paz, Bolivia, Universidad Catolica Boliviana “San
Pablo” (UCB), 20 October
5) Medellin, Colombia, Universidad de Antioquia (UDEA),
22 October
6) Medellin, Colombia, Universidad Pontificia Bolivariana
(UPB), 23 October
7) Bogota, Colombia, Universidad Distrital Francisco Jose de
Caldas (UDFJC), 24 October
8) Bogota, Colombia, Universidad Nacional De Colombia
(UNAL), 25 October
Lima, Peru
My stay and lectures in Lima were well organized by Fredy
Campos, Chair of the Peru Chapter. Lectures were given at
UNI and Centro de Tecnologias de Informacion y Comunicaciones (CTIC), where I was welcomed by the director Doris
Rojas Mendoza. Unfortunately, my stay in Lima was very short
and busy, with almost no free time to visit places. I arrived late
afternoon on the 13th, gave two lectures on the 14th, and left
Me (3rd from left), Doris Rojas Mendoza (5th), Fredy Campos
(7th), and other volunteers of the Lima ComSoc Chapter after
my lecture at Universidad Nacional de Ingegneria, Centro de
Tecnologias de Informacion y Comunicaciones, Lima, Peru.
for Cuzco in the early afternoon of the 15th. Therefore, I had
almost no time to visit Lima, which alone would deserve at
least one week just to appreciate its atmosphere, people,
numerous historical places, and museums. I had only a few
hours, on the evening of the 13th and the morning of the 15th
before heading to the airport, to walk around the historical
center and visit the two main archeological museums.
Cuzco, Peru
In Cuzco I gave the keynote talk “Synchronization of NextGeneration Networks” at the ANDESCON 2008 conference
on the morning of 16 October. I tuned the lecture to a tutorial level, because the audience background was heterogeneous
and more oriented to electronic engineering. My stay and lectures in Cuzco were organized by Cesar Chamochumbi, Chair
of the Peru Section, and Fredy Campos.
The altitude of Cuzco is 3400 m. At this altitude, in Italy I
am used to skiing on glaciers in temperatures as low as –25°C.
Cuzco was warm instead. I very much enjoyed this new feeling. The afternoon of 16 October I went to visit the Inca
Archaeological Park of Sacsayhuaman near Cuzco, consisting
of four sites with temples, buildings, and a fortress, built by
Incas before 1500 AD. On 17 October I had a day trip to
Machu Picchu. Machu Picchu is a wonder. The magic of the
lost city, surrounded by high mysterious mountains and
forests, is breathtaking. I walked a lot up and down the site,
and followed the two-hour round-trip trail to the Puerta del
Sol, the ancient entry gate to the site from the Inca Trail.
(Continued on Newsletter page 4)
Global Communications Newsletter • May 2009
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Ben Arabi, a New Spanish Supercomputer Connected with the World
By Joan Garcia-Haro and Manuel Escudero-Sanchez, Spain
During mid-March 2009, a new supercomputer called Ben
Arabi, located in the Region of Murcia, Spain, began to serve
to research centers and private companies located in the
regional and national areas. The name, a little bizarre, comes
from a distinguished philosopher of the medieval Kingdom of
Murcia who lived around the 12th century.
The Ben Arabi singular computing equipment was added to
the Spanish Supercomputer Network (RES). Previously, RES
consisted of a network of seven supercomputers: Mare Nostrum
(Barcelona), Magerit (Madrid), Altamira (Cantabria), La Palma
(Islas Canarias), Picasso (Málaga), Tirant (Valencia), and Cesar
Augusta (Zaragoza). In addition, the Ben Arabi supercomputer
joins the Ibergrid initiative, which promotes cooperative
research projects along the Iberian Peninsula. It is of course also
connected to the Spanish Academic and Research network as
well as to the HP CAST IBERICA (a proprietary network connecting all HP systems users devoted to intensive scientific computing). Ben Arabi joined the international grid efforts linking
the most prestigious supercomputing centers in the world. In
any case, the incorporation of Ben Arabi extends the geographical influence of all these networks to the southeast of Spain.
Therefore, it is expected that with this high tech investment both
the research community and the private sector will be able to
take advantage of a first-level computing infrastructure in order
to increase their productivity and competitiveness.
Ben Arabi has been installed in the Parque Científico de
Murcia, an institution conceived as a space of excellence and
innovation encouraging collaboration between academia and
industry, intended to revitalize technology transfer and competitiveness in the regional economic system. The Ben Arabi
computer was designed and developed by Hewlett-Packard. It
has one node (based on shared memory technology) with 128
cores and a set of 816 nodes (of the blade type). It is able to
perform up to 10.6 TFLOPS (tera-floating point operations
Detail of the Ben Arabi supercomputer.
per second). This capacity makes Ben Arabi the fourth most
powerful Spanish supercomputer. Since 2 September 2008,
Hewlett-Packard Spain along with CD-ROM S.A. (a local
company) have taken the responsibility to install and maintain
over time the hardware and software required. On the other
hand, IBM Global Services has been responsible for deploying
the necessary complementary infrastructure (air conditioned,
power generator, fire detection system, uninterruptible power
supply, etc.) at the supercomputer premises.
Like other European countries, the Spanish productivity sector is being gradually delocalized to Asia or Eastern Europe.
For this reason, the Autonomous Government of Murcia has
made this technological decision, knowing that the future of the
Murcia region must move towar the knowledge society.
IEEE ComSoc’s New Certification in
Wireless Communication Engineering Technologies
By Rolf Frantz, Telcordia, USA
In 2006, responding to the needs of its members who work in
industry, ComSoc identified a certification program as a way to
help these individuals enhance and demonstrate their knowledge of key technologies. Certification was also recognized as a
way to help employers identify employees and job applicants
who have the skills and knowledge to succeed. Of the numerous
“hot topics” in communications that could have been selected
for the first certification program, wireless was chosen because
of the rapid pace of technological change. In addition, the
tremendous growth of the industry has left employers struggling
at times to find qualified employees to design, develop, deploy,
and implement new products and services.
The IEEE ComSoc Wireless Communication Engineering
Technologies (WCET) certification program awards the IEEE
Wireless Communication Professional (IEEE WCP) credential
to candidates who pass a rigorous examination. The exam,
offered by computer-based testing at centers around the world,
covers seven technical areas that span the breadth of wireless
communications technology: RF Engineering, Propagation, and
Antennas; Wireless Access Technologies; Network and Service
Architecture; Network Management and Security; Facilities
Infrastructure; Agreements, Standards, Policies, and Regulations; and Fundamental Knowledge. The 150 multiple-choice
questions on the exam were created by practicing professionals
2
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in the wireless industry. They were vetted by a committee of
wireless experts and assembled into an exam focused on testing
the practical skills and applied knowledge employers in the wireless industry are seeking. Because the exam content is vendor
neutral and trans-national, acquiring the credential can open up
opportunities, whether within the same company or in a new
company, in new technical areas, or even in other countries.
Candidates who have obtained the IEEE WCP credential
report that preparing for the exam helped them learn their
strengths and weaknesses. They see the certification as help in
finding a better job and providing a level of trust in dealing with
customers. One has reported that having the credential was a
distinguishing factor in being awarded a consulting assignment.
Another has said that he would weigh the IEEE WCP credential as a factor in making hiring decisions.
Potential applicants for the WCET exam have a wide range
of resources to assist them, including a free Candidate’s Handbook, a free subscription to a bimonthly e-newsletter, periodic
free webinars, and free access, via the WCET Website at http://
____
www.ieee-wcet.org, to a glossary of common wireless communications terms, a list of sample references, sample exam questions, and a list of known providers of WCET-focused training.
Applicants can also purchase a practice exam, which they can
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Spectrum Research Collaboration Program
By Mohd Redza Fahlawi, Malaysian Communications and Multimedia Commission,
and Borhanuddin Mohd Ali, University Putra, Malaysia
The rapid advancement in wireless communications
requires ever increasing radio spectrum, and this demand calls
for efficient spectrum management. Balancing the spectrum
needs of various parties or services based on demands from,
for example, defense, government and public safety, private,
leisure, and commercial services, is a complex exercise and
requires a high level of expertise and foresight.
Realizing this, Malaysia’s communications regulator, the
Malaysian Communications and Multimedia Commission (MCMC
or SKMM in Malaysian) has initiated the Spectrum Research Collaboration Program (SRCP) to invite universities and companies
to conduct collaborative research on various aspects of spectrum
management. A fund of RM4 million has been allocated, and 11
projects have been awarded as an initial phase. The overall objective of this program is to improve the administrative, regulatory,
and technical expertise of frequency management in Malaysia.
Research themes derived from the key focus areas of
SRCP have been identified for researchers to formulate their
research proposals: emerging wireless technologies, spectrum
management, and spectrum and us. A theme may also be
adopted from the agenda items of the World Radicommunications Conference (WRC).
Under the theme of emerging wireless technologies, there
is a need to study their impact on spectrum use, their compatibility or sharing possibilities, and other constraints. Some
examples are high-altitude platform stations, ultra wideband,
white space communications, and the use of software, cognitive radios, and other alternative technologies.
In spectrum management, issues unique to the tropical
region such as rain fade for frequencies above 25 GHz and
the impact of foliage due to the dense tropical forest are studied in order to better handle the constraints and design appropriate mitigation techniques.
Safety of users of mobile phones is another area of interest
due to the increasing concern of the public about radio frequency radiation emitted from telecommunications base transmission stations and their own mobile phones. Their concerns
stem from frequent reports on the dangers of these radiations
emanating from the ever increasing numbers of BTSs in their
surroundings. Through emission level studies in our environment, these concerns can be put into proper perspective for the
public to understand and be accurately educated on the issues.
Regulatory rules can be instituted regarding transmitter placements to ensure compliance with an accepted safety standard.
On the theme of spectrum and us, research addresses the
social impact of various communication technologies, whether
in urban communities or rural. The findings are of interest to
various bodies in addressing the question of digital inclusion.
Services can then be rolled out in collaboration with related
government departments and stakeholders in order to make
sure that takeup is effective and thus contributes to improved
living conditions and productivity for the targeted groups.
The findings arising from the research are shared with interested parties, and SKMM launched a Web collaboration portal
in 2007 to share and disseminate the knowledge as well as
increase networking (http://www.spectrumresearch.com.my).
The portal is also meant for conducting online discussion of the
research topics, developing new ideas for new research subjects,
and also announcing upcoming spectrum related events.
Research Projects in 2007
For 2007, nine different subjects were awarded under five
different themes shown in Table 1.
One important precondition for successful consideration of
a project is that it needs to be collaborative in nature, involving more than one university, or among universities and
industry. Partnerships among universities are best suited when
the researchers must be independent with no conflict of interest; one example us the study of radio frequency radiation,
which involves three universities and no industry involvement.
On the other hand, research that involves testbed implementation is bes conducted in partnership with an industry player
that would have appropriate facilities on which to base measurements, thus saving time and costs. One example is the
No. Research subjects
Universities
Collaborative partners
1
Impact on the society
Universiti Teknlogi Malaysia (UTM)
University of Sydney, International Islamic
Universiti Malaysia (IIUM), University of Kuala
Lumpur
Universiti Kebangsaan Malaysia (UKM)
Universiti Utara Malaysia (UUM)
2
Radiation hazard
Universiti Tenaga Malaysia (Uniten)
UTM
3
Spectrum cost vs network cost
Universiti of Nottingham in Malaysia
First Principle Sdn Bhd
4
Cognitive radio
UTM
Uniten, IIUM
5
Frequency adaptive HF systems
UTM
Universiti Malaysia Pahang, Malaysian Red
Crescent Society, RF Communication (a private
company)
6
Frequency use above 25 GHz
Universiti Putra Malaysia
UTM, Universiti Sains Malaysia, IIUM Malaysia,
CRC (Canada)
Multimedia Universiti (MMU)
Malaysian University of Science and Technology
7
Spectrum needs for IMT-Advanced UTM
UKM, Maxis (a mobile operator)
8
Coexistence in extended C-band
MMU
MIMOS Bhd (a government research institution)
9
Synergizing 2G, 3G and WiMax
Universiti Malaya
DiGi (a mobile operator)
TABLE 1: The different research subjects and the universities involved for the first phase in 2007.
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DISTINGUISHED LECTURE/continued from page 1
La Paz, Bolivia
The trip from Cuzco to La Paz took me a good 10 hours, with a
six-hour layover in the Lima airport. I thought it was a shame to
waste this time in the airport, so I left my luggage and laptop at the
airport and went to downtown Lima for a relaxing couple of hours.
Sandra Hidalgo, chair of the Bolivia Chapter, organized my stay
and lectures in La Paz perfectly, treating me like one of her family.
In La Paz, two lectures were scheduled on 20 October at UCB, but
this plan had to be changed. That same day, Bolivia’s President Evo
Morales organized a mass demonstration of poor campesinos in La
Paz. UCB, surprisingly enough, decided to suspend all activities,
including my lecture, fearing the possibility of incidents. Actually,
they demonstrated noisily but peacefully until late night. We had to
move to the public National University: only 20 students were able
to attend rather than the more than 100 initially expected.
On Sunday 19 October, Sandra organized a nice tour of Lake Titicaca for me with her family. We spent one hour in a small rowboat
on the water, enjoying the warm sun and the clear blue sky at the
outstanding altitude of 4000 m. On the afternoon of 20 October after
the lecture, I went on my own by taxi to visit the Valley of the Moon,
hidden somewhere among the amazing dry mountains around the
huge depression where La Paz lies. This park features surprising pinnacles and cavities made of soft white sandstone eroded by rain.
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in wonderful green country and has a mild climate. It is also
famous as the city where the artist Botero was born. In the
center the nice Plaza Botero features a dozen of his big
bronze characteristic statues. The Museo Botero cannot be
missed by any tourist with an interest in art.
Bogota, Colombia
In Bogota, I gave two lectures at UDFJC and UNAL on 24
and 25 October. The lecture at UNAL inaugurated the new
ComSoc Student Branch. After the lecture, I had the pleasure
of toasting the new Branch with numerous students and Zoila
Ramos, Coordinator of the Telecommunications Master.
My stay and lectures in Bogota were effectively organized
by Carlos Andres Lozano Garzon, Chair of the Colombia
Chapter. Former Chapter Chair Jose-David Cely was also
always present. This was my second time in Bogota. In the
free time after lectures, I enjoyed very much visiting again the
Botero Museum and just strolling around the city mixing with
the busy crowd.
The full report is posted at http://www.comsoc.org/socstr/
org/chapters/LADLT/index.html.
SPECTRUM RESEARCH/continued from page 3
study of spectrum needs for IMT-Advanced.
Medellin, Colombia
The trip from La Paz to Medellin was very long: it took me 12
hours including overheads. In Medellin I gave two lectures at
UDEA and UPB on 22 and 23 October. I also had an interesting
meeting at EAFIT University. The activities of ARTICA, an
alliance between the universities of Medellin (UDEA, UPB, Universidad Nacional, EAFIT) and industry, were presented to me.
My stay and lectures in Medellin were organized perfectly
by Ana Maria Cardenas, professor at UPB. Medellin is located
Research Projects 2008
The second round of research collaboration was opened in
July 2008. A total of 31 submissions were received, quite a significant increase from the number received in the first round
in 2007. This is a good indication that the SRCP is gaining
popularity in the local research community and will further
help to grow the number of experts in the spectrum field. Of
the 31 submissions, six research proposals were selected to be
granted research funds for 2008.
Conclusion:
Global
Newsletter
www.comsoc.org/pubs/gcn
STEFANO BREGNI
Editor
Politecnico di Milano - Dept. of Electronics and Information
Piazza Leonardo da Vinci 32, 20133 MILANO MI, Italy
Ph.: +39-02-2399.3503 - Fax: +39-02-2399.3413
Email: ____________
bregni@elet.polimi.it, s.bregni@ieee.org
__________
IEEE COMMUNICATIONS SOCIETY
MARK KAROL, VICE-PRESIDENT CONFERENCES
BYEONG GI LEE, VICE-PRESIDENT MEMBER RELATIONS
NELSON FONSECA, DIRECTOR OF LA REGION
GABE JAKOBSON, DIRECTOR OF NA REGION
TARIQ DURRANI, DIRECTOR OF EAME REGION
ZHISHENG NIU, DIRECTOR OF AP REGION
ROBERTO SARACCO, DIRECTOR OF SISTER AND RELATED SOCIETIES
REGIONAL CORRESPONDENTS WHO CONTRIBUTED TO THIS ISSUE
BORHANUDIN MOHD ALI, MALAYSIA (BORHAN
@ENG.UPM.EDU.MY)
_______________
JOSÉ MARIA MALGOSA-SANAHUJA, SPAIN (_______________
JOSEM@MALGOSA@UPCT.ES)
®
A publication of the
IEEE Communications Society
4
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The indications are that there is a lot of interest in spectrum related research in Malaysia. The rights to the outcome
of this research rests with the respective research institutionsm
but SKMM reserves the right to utilize them in order to assist
it in drafting future policies, drawing suitable guidelines, and
responding to WRC questions. Collaboration with overseas
partners is also very much encouraged. This will serve to
mutually enhance understanding of spectrum issues from a
more global perspective.
WIRELESS CERTIFICATION/continued from page 2
take multiple times to help assess their readiness and focus their
studies in preparation for the certification exam. Later this
spring, the Wireless Engineering Body of Knowledge, a book that
surveys the seven technical areas covered by the exam, will be
available for purchase from ComSoc or Wiley.
The certification exam was first offered in fall 2008. Of the
candidates who took that exam, 85 percent passed and were
awarded the IEEE WCP credential. The spring 2009 exam was
offered in late March, and the results should be available shortly.
The application window for the fall 2009 exam opens 6 July, and
the exam itself will be administered between 12–31 October. For
further information about WCET certification, visit the Website
or email any questions to cert@comsoc.org.
____________ Members of the
team that developed the WCET program are also attending conferences and IEEE meetings around the world. Watch for
announcements of presentations or visit the IEEE ComSoc
booth in conference exhibit areas for additional information
about the benefits of obtaining IEEE WCET certification.
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TA B L E O F C O N T E N T S
Digital & Wireless Communications
Adaptive Signal Processing in Wireless
Communications, Two-Volume Set . . . . .3
Optical Wireless Communications:
IR for Wireless Connectivity . . . . . . . . . .3
IP Multimedia Subsystem (IMS)
Handbook . . . . . . . . . . . . . . . . . . . . . . .4
RFID and Sensor Networks: Architectures,
Protocols, Security and Integrations . . . .4
Contemporary Coding Techniques and
Applications for Mobile Communications . .4
Vehicular Networks: Techniques,
Standards, and Applications . . . . . . . . . .4
Unlicensed Mobile Access Technology:
Protocols, Architectures, Security,
Standards and Applications . . . . . . . . . . .9
Circuits at the Nanoscale:
Communications, Imaging,
and Sensing . . . . . . . . . . . . . . . . . . . . .12
Broadband Mobile Multimedia:
Techniques and Applications . . . . . . . . .9
2-D Electromagnetic Simulation of
Passive Microstrip Circuits . . . . . . . . . . .12
Data Scheduling and Transmission
Strategies in Asymmetric
Telecommunication Environments . . . . .9
Networks-on-Chips: Theory
and Practice . . . . . . . . . . . . . . . . . . . . .13
The Internet of Things: From RFID
to the Next-Generation Pervasive
Networked Systems . . . . . . . . . . . . . . . .9
Handbook of Mobile Broadcasting:
DVB-H, DMB, ISDB-T, AND
Radar Signal Analysis and Processing
Using MATLAB . . . . . . . . . . . . . . . . . . .13
MEDIAFLO . . . . . . . . . . . . . . . . . . . . .9
Sensor Array Signal Processing,
Second Edition . . . . . . . . . . . . . . . . . . .13
Networking Communications
Brief Notes in Advanced DSP:
Fourier Analysis with MATLAB . . . . . . .13
Energy Efficient Hardware: Software
Co-Synthesis Using Reconfigurable
Hardware . . . . . . . . . . . . . . . . . . . . . . .10
RFID Handbook: Applications,
Technology, Security, and Privacy . . . . .13
Network Design for IP Convergence . . .10
Electromagnetics
Wireless Quality of Service: Techniques,
Standards, and Applications . . . . . . . . . .6
VMware Certified Professional
Test Prep . . . . . . . . . . . . . . . . . . . . . . .10
Mobile Telemedicine: A Computing
and Networking Perspective . . . . . . . . . .6
Performance Analysis of Queuing
and Computer Networks . . . . . . . . . . . .10
Numerical Techniques in
Electromagnetics with MATLAB®,
Third Edition . . . . . . . . . . . . . . . . . . .14
Millimeter Wave Technology in
Wireless PAN, LAN, and MAN . . . . . . . . .6
SIP Handbook: Services, Technologies,
and Security of Session Initiation
Protocol . . . . . . . . . . . . . . . . . . . . . . . .10
Security in RFID and Sensor Networks . . .5
Satellite Systems Engineering in
an IPv6 Environment . . . . . . . . . . . . . . .5
Cognitive Radio Networks . . . . . . . . . . .5
Wireless Multimedia Communications:
Convergence, DSP, QoS, and Security . . . .5
MEMS and Nanotechnology-Based
Sensors and Devices for Communications,
Medical and Aerospace Applications . . . .6
Metamaterials Handbook,
Two Volume Slipcase Set . . . . . . . . . .14
Surface Impedance Boundary Conditions:
A Comprehensive Approach . . . . . . . . .14
Enterprise Systems Backup and
Recovery: A Corporate Insurance Policy . .10
Ionosphere and Applied Aspects of
Radio Communication and Radar . . . .14
Advances in Semantic Media Adaptation
and Personalization, Volume 2 . . . . . . . .6
Communications with Optics,
Lasers, & Photonics
RF and Microwave Handbook,
Second Edition, 3 Volume Set . . . . . . .14
Telecomunications
Photonic MEMS Devices: Design,
Fabrication and Control . . . . . . . . . . . .11
Computer Engineering
Security in Wireless Mesh Networks . . . .6
Long Term Evolution: 3GPP
LTE Radio and Cellular Technology . . . .7
Converging NGN Wireline and Mobile
3G Networks with IMS: Converging
NGN and 3G Mobile . . . . . . . . . . . . . . .7
Introduction to Communications
Technologies: A Guide for Non-Engineers,
Second Edition . . . . . . . . . . . . . . . . . . . .7
Carrier Ethernet: Providing the Need
for Speed . . . . . . . . . . . . . . . . . . . . . . . .8
Practical Applications of Microresonators
in Optics and Photonics . . . . . . . . . . . .11
Optoelectronics: Infrared-Visable
Ultraviolet Devices and Applications,
Second Edition . . . . . . . . . . . . . . . . . . .11
WiMAX Network Planning and
Optimization . . . . . . . . . . . . . . . . . . . . . .8
Grid Computing: Infrastructure,
Service, and Applications . . . . . . . . . . .15
The Computer Engineering Handbook,
Second Edition, Two-Volume Set . . . . .15
Advanced Linear Algebra for
Engineers with MATLAB® . . . . . . . . . . .16
Digital Optical Communications . . . . . .11
Slow Light: Science and Applications . .11
Practical Matlab® for Engineers,
Two-Volume Set . . . . . . . . . . . . . . . . . .16
Circuits & Signals
Standards, Conformity Assessment,
and Accreditation for Engineers . . . . . .16
Cooperative Wireless Communications . .8
The Circuits and Filters Handbook, Third
Edition, (Five Volume Slipcase Set) . . . .12
VoIP Handbook: Applications,
Technologies, Reliability, and Security . . .9
Embedded Systems Handbook,
Second Edition . . . . . . . . . . . . . . . . . . .12
Communications
ARM Assembly Language:
Fundamentals and Techniques . . . . . . .15
Photoacoustic Imaging and
Spectroscopy . . . . . . . . . . . . . . . . . . . .11
Security of Mobile Communications . . . .8
IEEE
Signals, Systems, Transforms, and
Digital Signal Processing
with MATLAB® . . . . . . . . . . . . . . . . . . .13
MBCOM09 MC
4.2709gtr
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DIGITAL & WIRELESS COMMUNICATIONS
New!
Adaptive Signal Processing
in Wireless Communications
Optical Wireless Communications
Two-Volume Set
Roberto Ramirez-Iniguez
Edited by
Glasgow Caledonian University, Scotland
Mohamed Ibnkahla
Sevia M. Idrus
Queen's University, Kingston, Ontario, Canada
From adaptive signal processing to cross layer design, Adaptive
Signal Processing in Wireless Communications covers all
aspects of adaptation in wireless communications. Each volume
provides a unified framework for understanding adaptation and
relates various specializations through common terminologies. In
addition to simplified state-of-the-art cross layer design
approaches, they also describe advanced techniques, such as
adaptive resource management, 4G communications, and energy
and mobility aware MAC protocols.
Volume I
The first volume in the set is devoted to adaptation in the physical layer. It surveys adaptive signal processing techniques used
in current and future wireless communication systems. Featuring
the work of international experts, it covers adaptive channel
modeling, identification and equalization, adaptive modulation
and coding, adaptive multiple-input-multiple-output (MIMO)
systems, and cooperative diversity. It also addresses hardware
implementation, reconfigurable processing, and cognitive radio.
Catalog no. 46012, January 2009
520 pp., ISBN: 987-1-4200-4601-4, $99.95 / £63.99
IR for Wireless Connectivity
Universiti Teknologi Malaysia, Skudai Johor
Ziran Sun
Newbury, UK
Providing an extensive review of system features for indoor and
outdoor use, Optical Wireless Communications: IR for
Wireless Connectivity offers a comprehensive description of the
technical challenges and limitations inherent in this field. This
book covers the principles of optical wireless communication systems and the fundamental operation of the main components of a
wireless infrared system. It presents examples of current applications and future trends and also addresses challenges faced in
designing a wireless infrared system. Featuring a reader-friendly
approach, this text includes figures, illustrations, graphs, charts,
summaries, and appendices to facilitate understanding.
Features
• Reviews optical wireless communication features for indoor
and outdoor use
• Explains the benefits and the limitations of infrared links
• Describes design fundamentals and different possible
configurations
• Addresses optical safety issues for optical wireless systems
Volume II
The second volume in the set is devoted to adaptation in the data
link, network, and application layers. It presents current adaptation techniques and methodologies, including cross-layer adaptation, joint signal processing, coding and networking, selfishness in mobile ad hoc networks, cooperative and opportunistic
protocols, adaptation techniques for multimedia support,
self–organizing routing, and tunable security services. It presents
new theoretical paradigms and findings supported with various
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528 pp., ISBN: 987-1-4200-4603-8, $99.95 / £63.99
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1048 pp., ISBN: 978-1-4200-4599-4, $159.95 / £99.00
Contents abridged
Atmospheric Transmission Limitations. Data Transmission
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Concentration. Optical Concentrators. Optical Wireless
Transmitter Design. Optical Wireless Receiver Design.
Modulation, Coding, and Multiple Access. IrDA protocols.
Wireless IR Networking. References.
Catalog no. AU7209, 2008
376 pp., ISBN: 978-0-8493-7209-4, $89.95 / £57.99
Please visit www.crcpress.com
for more information and
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For discount use promo code 366DE when ordering online at www.crcpress.com
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New!
New!
IP Multimedia Subsystem
(IMS) Handbook
Edited by
Mohammad Ilyas
Contemporary Coding
Techniques and
Applications for
Mobile Communications
Florida Atlantic University, Boca Raton, USA
Osman Nuri Ucan
Syed A.Ahson
Istanbul University, Turkey
Microsoft Corporation, Bellevue, Washington, USA
Onur Osman
IMS promises to be a cost-effective evolution path to future
wireless and wireline convergences that meet next-generation
service demands and requirements. Organized into three sections, the IP Multimedia Subsystem (IMS) Handbook is a
one-stop guide that focuses on the concepts, technologies, and
services of IMS. Featuring articles authored by leading experts in
the field, this comprehensive volume provides technical information on all aspects of this exciting technology. The book also
explores future research directions and contains extensive bibliographies in each chapter to assist readers in further study.
Istanbul Commerce University, Turkey
560 pp., ISBN: 978-1-4200-6459-9, $139.95 / £89.00
Modern error control coding methods based on turbo coding
have essentially solved the problem of reliable data communications over noisy channels. Contemporary Coding
Techniques and Applications for Mobile Communications
provides a clear, comprehensive, and practical foundation on
the basics of contemporary coding techniques and their applications for mobile communications. The first half of the text presents fundamental information on modulation, multiplexing,
channel models, and traditional coding methods. The second
half explains advanced coding techniques, provides simulation
results, and compares them with related methods. The book
also provides new coding algorithms and explores new research
areas such as image transmission with step-by-step guidelines.
Catalog no. AU5461, May 2009
c. 352 pp., ISBN: 978-1-4200-5461-3, $99.95 / £55.99
on!
Coming So
RFID and Sensor Networks
Architectures, Protocols, Security
and Integrations
Edited by
Vehicular Networks
Techniques, Standards,
and Applications
Yan Zhang
Edited by
Simula Research Laboratory, Lysaker, Norway
Hassnaa Moustafa
Laurence T.Yang
France Telecom Research and Development
St. Francis Xavier University, Antigonish NS, Canada
Yan Zhang
Jiming Chen
Zhejiang University, Hangzhou, China
Integrating radio frequency identification (RFID) and wireless
sensor networks (WSN) for the first time, this comprehensive
text explains the importance of their complementary nature,
flexible combination, and ubiquitous computing. With a section
devoted to each individual element, the text covers the tags,
readers, and middleware associated with RFID. It then provides
insight into the routing, medium access control, and cross-layer
optimization of WSN. The book discusses the enhanced visibility and monitoring capability that is possible and observes practical uses such as a smart home, a surveillance system, and
applications for personal health care.
Vehicular networks have special behavior and characteristics distinguishing them from other types of mobile networks. This book
illustrates their benefits and real-life applications. It examines
possible services that these networks can provide and presents
their possible deployment architectures, while also showing the
roles of the involved contributors (networks operators, car manufacturers, service providers, and governmental authorities). The
book explores the technical challenges in deployment, such as
MAC protocols, routing, information dissemination, dynamic IP
autoconfiguration, mobility management, security, and the privacy of drivers and passengers. In addition, it considers possible
business models for deploying such networks.
Catalog no. AU7777, November 2009
c. 584 pp., ISBN: 978-1-4200-7777-3, $99.95 / £60.99
Catalog no. AU8571, April 2009
450 pp., ISBN: 978-1-4200-8571-6, $99.95 / £60.99
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New!
Security in RFID and
Sensor Networks
Edited by
New!
Cognitive Radio Networks
Yan Zhang
Edited by
Yang Xiao and Fei Hu
Paris Kitsos
The University of Alabama, Tuscaloosa, USA
Hellenic Open University, Patras, Greece
Interest in radio frequency identification (RFID) and wireless
sensor networks (WSNs) has exploded globally in industry and
academia, but security is one of the key issues standing in the
way of broad deployment of RFID and WSN systems. Broken
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comprehensive discussion on the fundamentals, security challenges, and solutions in RFID, WSNs, and integrated RFID &
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The fast-paced growth in wireless services over the past several
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resources of the available spectrum. Cognitive radio network
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existing users. This book covers a range of cognitive radio network issues. It addresses the physical layer, medium access control, the routing layer, cross-layer considerations and advanced
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New!
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Engineering in an
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K.R. Rao
Daniel Minoli
University of Belgrade, Serbia
SES Americom, Princeton, New Jersey, USA
A practical guide to satellite transmission engineering, this book
has three distinguishing features. It focuses more on practical
results and less on the actual derivation of the mathematical
equations, highlights the use of satellite transmission in an ipv6
environment, and applies the theory to sensor networks, IPTV
distribution, and DVB-H-based delivery of TV signals to phones.
Topics include electromagnetic propagation, modulation and
multiplexing techniques, link budget analysis, IPv6 and
TCP/IPv6 issues, and very small aperture terminals systems. The
book concludes with coverage of applications such as sensor
networks, IP multicast, IPTV, and DVB-H.
Blending coverage of wireless multimedia communications with
convergence technologies, digital signal processing, quality of
service, and security, this book provides a unified approach to
introducing the full spectrum of engineering demands across all
wireless networks and systems. The authors identify problems
that cause information loss in point-to-point signal transmission
through wireless channel and discuss techniques for minimizing
the information loss. They use examples that illustrate the differences in implementing various systems, ranging from cellular
voice telephony to wireless Internet access. The book distills the
underlying theory, concepts, and principles into a comprehensive resource.
Catalog no. AU7868, February 2009
360 pp., ISBN: 978-1-4200-7868-8, $99.95 / £55.99
344 pp., ISBN: 978-0-8493-8582-7, $99.95 / £63.99
University of Texas at Arlington, USA
Zoran S. Bojkovic and
Dragorad A. Milovanovic
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Wireless Quality of Service
Techniques, Standards,
and Applications
Edited by
New!
Maode Ma
Nanyang Technological University, Singapore
Mieso K. Denko
A.R. Jha
Jha Technical Consulting Service, Cerritos, California, USA
University of Guelph, Ontario, Canada
Yan Zhang
This volume addresses the QoS issues found in many wireless networks, including LANs, PANs, MANs, 3G, mobile ad hoc, sensor,
and heterogeneous. It presents techniques to combat QoS problems, covers standards of different wireless networks and the QoS
service frameworks specified in them, and explores progress on
improving the performance of QoS services in wireless networks.
376 pp., ISBN: 978-1-4200-5130-8, $89.95 / £57.99
“…provides a wide-lens perspective of
the field.
—Dr. Ashok K. Sinha, Retired Senior Vice President, Applied Materials, Inc.
Exploring the potential of using MEMS and NT in sensors and
devices, this book describes packaging details, materials, their
properties, and fabrication requirements vital for design, development, and testing. The author covers various types of MEMSand NT-based sensors and devices and discusses how they are
used in a number of applications.
432 pp., ISBN: 978-0-8493-8069-3, $129.95 / £82.00
Security in Wireless
Mesh Networks
Mobile Telemedicine
A Computing and
Networking Perspective
Edited by
New!
Yan Zhang
Edited by
Yang Xiao
Jun Zheng
University of Alabama, Tuscaloosa, USA
City University of New York, USA
Hui Chen
Honglin Hu
Virginia State University, Petersburg, USA
This work examines computing and network
dilemmas which arise from wireless and
mobile telemedicine. It provides an overview of patient care and
monitoring, discusses the use of telemedicine in cardiology and
diabetes, analyzes security issues and privacy considerations,
examines issues relating to networking support, and reviews the
opportunities and challenges faced by those working with this
exciting technology.
440 pp., ISBN: 978-1-4200-6046-1, $79.95 / £49.99
Millimeter Wave Technology
in Wireless PAN, LAN,
and MAN
Edited by
Shanghai Research Center for Wireless
Communications, China
This reference provides an introduction to security issues, recent
advances, and future directions in wireless mesh networks. It examines the emerging standards of security, addressing authentication,
access control and authorization, attacks, privacy and trust, encryption, key management, identity management, DoS attacks, intrusion
detection and protection, secure routing, security standards, security
policy, and includes numerous case studies and various applications.
552 pp., ISBN: 978-0-8493-8250-5, $89.95 / £57.99
Advances in Semantic
Media Adaptation
New!
and Personalization
Volume 2
Edited by
Shao-Qiu Xiao
University of Electronic Science and Technology of China
Ming-Tuo Zhou
Marios C. Angelides
Brunel University, Middlesex, UK
Phivos Mylonas
National Institute of Information and
Communications Technology, Singapore
National Technical University of Athens, Greece
Manolis Wallace
Yan Zhang
University of Peloponnese, Tripoli, Greece
This reference provides comprehensive coverage of the basics
and recent advances in millimeter wave technology in the wireless personal area network, wireless local area network, and
wireless metropolitan area network. The book covers various
millimeter wave circuit, system, and architecture. It also explores
emerging standardization activities and specifications.
A collection of papers presented at the 2007 2nd International
Workshop on Semantic Media Adaptation and Personalization, this
volume explores recent developments in the field of semantic
media adaptation and personalization. Topics discussed include
the challenges of collaborative content modeling, video adaptation, information retrieval techniques for semantic media adaptation, and podcasting.
448 pp., ISBN: 978-0-8493-8227-7, $129.95 / £82.00
456 pp., ISBN: 978-1-4200-7664-6, $129.95 / £78.99
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MEMS and NanotechnologyBased Sensors and Devices
for Communications, Medical
and Aerospace Applications
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TELECOMMUNICATIONS
New!
New!
Converging NGN Wireline
and Mobile 3G Networks
with IMS
Converging NGN and 3G Mobile
Rebecca Copeland
Long Term Evolution
3GPP LTE Radio and Cellular Technology
Edited by
Borko Furht
Syed A.Ahson
With coverage ranging from basic concepts to research grade
material to future directions, this handbook is a complete reference for technical information on all aspects of 3GPP LTE. It
details low chip rate, high-speed downlink/uplink packet access
(HSxPA)/TDSCDMA EV 1x, LTE TDD, and 3G TDD. It also introduces new technologies and covers methodologies to study the
performance of frequency allocation schemes. The book discusses the proposed architecture of Mobile IPRR and distributed
dynamic architecture in the wireless communication and
includes coverage of performance evaluation of the TD-SCDMA
LTE System.
Strategic IMS Solution Consultant, Warwickshire, UK
“…a very timely contribution to this field.
It is suitable for both lay people ... as well as more skilled
practitioners wanting to brush up on technical details ...”
—Mick Reeve, Fellow of the International Engineering Consortium
and the Royal Academy of Engineering,
Retired Chief Architect of BT Group CTO
This guide fosters a clearer understanding of the next generation
of converged communication. It centers on important aspects of
IMS that go beyond session control and multimedia handling to
include ID management, service profiles, event triggering, flowand event-based charging mechanisms, and service-based quality
of service. Network admission, security, border control, and legacy services are also examined.
518 pp., ISBN: 978-0-8493-9250-4, $89.95 / £57.99
Features
New!
• Includes contributions from international experts
• Addresses current and emerging LTE technologies
• Provides high-level overviews and detailed explanations of
HSPA and LTE as specified by GPP
• Presents the evolution map from TD-SCDMA to future
terrestrial universal radio environment TDD
• Explains the radio access technologies and key international
standards needed to move ahead to fully operational mobile
broadband
Introduction to
Communications
Technologies
Contents Abridged
Ball State University, Muncie, Indiana, USA
Evolution from TD-SCDMA to FuTURE. Radio-Interface Physical
Layer. Architecture and Protocol Support for Radio Resource
Management (RRM). MIMO OFDM Schemes for 3GPP LTE.
Single-Carrier Transmission for UTRA LTE Uplink. Cooperative
Transmission Schemes. Multihop Extensions to Cellular
Networks—the Benefit of Relaying for LTE. User Plane Protocol
Design for LTE System with Decode-Forward Type of Relay.
Radio Access Network VoIP Optimization and Performance on
3GPP HSPA/LTE. Early Real-Time Experiments and Field Trial
Measurements with 3GPP-LTE Air Interface Implemented on
Reconfigurable Hardware Platform. Measuring Performance of
3GPP LTE Terminals and Small Base Stations in Reverberation
Chambers.
Providing an accessible tutorial on telecommunications and network technologies, this text emphasizes the important relationship
between voice and data. This second edition has been substantially updated to reflect the latest cellular and mobile technologies,
including OFDM, IPv6, WCDMA, SD-CDMA, 4G, WiMAX, QoS,
MPLS, unified messaging, IP telephony, and residential convergence (smart home technology). It also features new chapters on
network management and security, as well as digital media. The
text covers a wide range of topics, from circuit switching and
packet switching technologies to wireless and video technologies.
Based on an actual course, the book provides an instructor’s manual with PowerPoint® slides, problems, and a detailed syllabus for
qualifying instructors.
488 pp., ISBN: 978-1-4200-7210-5, $99.95 / £60.99
328 pp., ISBN: 978-1-4200-4684-7, $69.95 / £44.99
A Guide for Non-Engineers,
Second Edition
Stephan Jones,Ron Kovac,& Frank M.Groom
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TELECOMMUNICATIONS
New!
Carrier Ethernet
Providing the Need for Speed
Gilbert Held
4-Degree Consulting, Macon, Georgia, USA
WiMAX Network Planning
and Optimization
Edited by
Ensuring seamless migration to Carrier Ethernet from existing technologies and integration with emerging services, this text provides
readers with the expert guidance needed to make full use of
Ethernet technology, both now and into the future.
As engaging as it is comprehensive, this volume:
• Examines the differences between the so-called flavors of
Ethernet
• Provides refreshers on virtual LANs, virtual private networks,
and Multi-Protocol Label Switching
• Details Carrier advantages over other modalities with regard
to network performance
• Explores Service Level Agreements, including ways to obtain
a quality of service for the movement of voice and real-time
video, and the creation of VLANs to facilitate the movement
of data
• Describes various services that can be enabled over an
Ethernet infrastructure
224 pp., ISBN: 978-1-4200-6039-3, $79.95 / £49.99
Yan Zhang
This book offers a comprehensive explanation on how to
dimension, plan, and optimize WiMAX networks. Part I introduces WiMAX networks architecture, physical layer, standard,
protocols, security mechanisms, and highly related radio access
technologies. It covers system framework, topology, capacity,
mobility management, handoff management, congestion control, medium access control (MAC), scheduling, Quality of
Service (QoS), and WiMAX mesh networks and security.
Enabling easy understanding of key concepts and technologies,
Part II presents practical examples and illustrative figures to
explain planning techniques and optimization algorithms.
451 pp., ISBN: 978-1-4200-6662-3, $119.95 / £72.99
New!
Cooperative Wireless
Communications
Edited by
New!
Yan Zhang
Security of Mobile
Communications
Hsiao-Hwa Chen
Noureddine Boudriga
Western Michigan University, Kalamazoo, USA
National Cheng Kung University, Taiwan
Mohsen Guizani
University of the 7th of November at Carthage, Tunisia
This innovative text provides comprehensive coverage of the
complex security issues that face the mobile communications
industry. Discussions include hacking and infecting with viruses; techniques used to provide access control, authentication,
and authorization; the security of SIM-like cards; standards
implemented by the GSM, third generation, WLAN, and ad-hoc
networks; the security of wireless sensor networks, satellite services, mobile e-services, and inter-system roaming and interconnecting systems; and the applications using IP mobility. Mobile
communications scientists, students, engineers, and telecom
service providers will find this to be an invaluable resource.
Cooperative devices are receiving greater focus in wireless communication as they substantially enhance system performance
by decreasing power consumption and packet loss rate, while
also increasing system capacity and network resilience.
Providing the vital background information needed for those
involved with the development and implementation of cooperative mechanisms, this volume introduces cooperative strategies
for infrastructure-based systems and for self-organizing multihop networks. Providing a key reference for researchers and
product developers, the text details those recent improvements
in a variety of cooperative mechanisms and frameworks that are
applicable in diverse scenarios.
Catalog no. AU7941, June 2009
c. 640 pp., ISBN: 978-0-8493-7941-3, $99.95 / £60.99
528 pp., ISBN: 978-1-4200-6469-8, $99.95 / £60.99
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TELECOMMUNICATIONS
VoIP Handbook
Data Scheduling and
Transmission Strategies
in Asymmetric
Telecommunication
Environments
Mohammad Ilyas
Navrati Saxena
Sungkyunkwan University, South Korea
From basic concepts to future research directions, this text provides technical information
on all aspects of Voice over Internet Protocol (VoIP). It explores
the wide range of applications that VoIP offers, including smartphones and access to emergency services. Leading experts offer
their perspectives on numerous related topics, including reliability
models, latest technologies, and security issues.
Abhishek Roy
Applications, Technologies,
Reliability, and Security
Edited by
Syed A.Ahson
New!
440 pp., ISBN: 978-1-4200-7020-0, $99.95 / £63.99
Unlicensed Mobile
Access Technology
New!
Protocols, Architectures, Security,
Standards and Applications
Edited by
Conexant Systems, Noida, India
While push and pull strategies both have value separately, it is
clear that any optimal solution requires a hybrid approach.
Written by highly respected pioneering researchers, this work
takes a practical approach. The authors discuss basic push and
pull strategies, examine the challenges posed by customer
requests and behavior, and define ideal hybrid strategies.
160 pp., ISBN: 978-1-4200-4655-7, $99.95 / £63.99
The Internet of Things
From RFID to the Next-Generation
Pervasive Networked Systems
Edited by
Lu Yan
Yan Zhang
Cambridge, UK
Simula Research Laboratory, Norway
Laurence T.Yang
St. Francis Xavier University, Canada
Jianhua Ma
Hosei University, Japan
This book provides a complete cross-reference on UMA technology and UMA-relevant technologies. Presenting a fundamental
introduction with definitions of concepts, explanations of protocols and emerging standards, and detailed discussions of applications, it covers system/network architecture, capacity, mobility
management, vertical handoff, and routing.
424 pp., ISBN: 978-1-4200-5537-5, $99.95 / £63.99
Broadband Mobile Multimedia
Techniques and Applications
Edited by
Yan Zhang
Yan Zhang
Laurence T.Yang
St. Francis Xavier University, Antigonish,
Nova Scotia, Canada
Huansheng Ning
Beijing University of Aeronautics & Astronautics, China
This reference provides comprehensive, technical, and practical
deploying policy guidance — covering fundamentals and recent
advances in pervasive networked systems. It addresses the conceptual and technical issues that influence the technology roadmap and
provides an in-depth introduction to the Internet of Things and its
effect on businesses and individuals.
336 pp., ISBN: 978-1-4200-5281-7, $99.95 / £63.99
Handbook of
Mobile Broadcasting
Auburn University, Alabama, USA
DVB-H, DMB, ISDB-T, AND
MEDIAFLO
Laurence T.Yang
Edited by
St. Francis Xavier University, Nova Scotia, Canada
Borko Furht
Thomas M. Chen
Southern Methodist University, Dallas, Texas, USA
Syed A.Ahson
This guide presents introductory concepts, fundamental techniques, current advances, and open issues. It examines the routing and cross-layer design issue of multimedia communication
over multihop wireless ad hoc and sensor networks, discusses
issues related to multimedia communications over WLANs, and
explores recent developments in QoS provisioning mechanisms
and other enabling technologies.
584 pp., ISBN: 978-1-4200-5184-1, $99.95 / £63.99
744 pp., ISBN: 978-1-4200-5386-9, $149.95 / £95.00
Shiwen Mao
This handbook presents technical standards and distribution
protocols, offering detailed coverage of video coding, including
design methodology and error resilience techniques; state-ofthe-art technologies such as signaling, optimization, implementation, and simulation; and applications of mobile broadcasting,
including emerging areas and new interactive services.
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NETWORKING COMMUNICATIONS
Energy Efficient Hardware
on!
Software Co-Synthesis Using
Coming So
Reconfigurable Hardware
Performance Analysis
of Queuing and
Computer Networks
Jingzhao Ou
G.R. Dattatreya
Xilinix, San Jose, California, USA
MITRE, Colorado Springs, Colorado, USA
Viktor K. Prasanna
This is the first research monograph to systematically address the
important topics related to energy efficient hardware-software cosynthesis using reconfigurable hardware. It provides a system-level
framework that allows high-level hardware-software design
description, co-simulation, and co-debugging and presents techniques for energy performance modeling.
With examples and exercises, this text develops simple models and analytical methods
from first principles to evaluate performance
metrics of various configurations of computer
systems and networks. It includes simple, analytically tractable
models, presents models for complex systems as analyzable modifications and/or interconnections of simple models, and contains
a wide variety of queuing models.
Catalog no. C7419, September 2009
c. 213 pp., ISBN: 978-1-58488-741-6, $99.95 / £60.99
Catalog no. C9861, 2008
472 pp., ISBN: 978-1-58488-986-1, $89.95 / £57.99
University of Southern California, Los Angeles, USA
SIP Handbook
Network Design
for IP Convergence
New!
Yezid Donoso
New!
Edited by
Universidad de los Andes, Bogota, Colombia
Syed A.Ahson
Emerging Internet Quality of Service mechanisms are leading to widespread use of real
time multimedia services however, this
requires drastically improved technology and
standards. To assist designers and operators,
this work offers an introduction to LAN/MAN/WAN network
design, architecture, and equipment. It describes routing architecture, covers IP protocols and interconnections, and looks at
designs and configurations for service connections.
Catalog no. AU6750, February 2009
306 pp., ISBN: 978-1-4200-6750-7, $79.95 / £44.99
New!
Mohammad Ilyas
This volume provides a powerful hands-on reference for designers and planners of Session Initiation (SIP) networks. It reviews
services associated with SIPs, examines technologies involved in
their utilization, and explores the myriad of security issues that
their use engenders. Because of the editors’ pivotal influence on
both the market and science, this work is certain to become the
definitive text on this emerging technology.
Catalog no. 6603X, January 2009
614 pp., ISBN: 978-1-4200-6603-6, $149.95 / £95.00
New!
N
VMware Certified
Professional Test Prep
Enterprise Systems
Backup and Recovery
Merle Ilgenfritz & John Ilgenfritz
Preston de Guise
A Corporate Insurance Policy
Ilgenfritz Consulting, LLC
IDATA Pty Ltd., Sydney, Australia
Written by VM-certified instructors with years
of professional and teaching experience,
VMware Certified Professional Test Prep is
the ultimate guide to the VCP exam. Its organized and highly practical approach helps
administrators successfully complete the exam while also maximizing their ability to apply this tool on the job. The guide covers the
body of knowledge required of a VMware certified professional
and provides the tools needed to keep that knowledge current.
This book provides organizations with a comprehensive understanding of the principles
involved in effective enterprise backups.
Instead of focusing on any individual backup
product, this book recommends corporate procedures and policies that need to be established for comprehensive data protection. It provides relevant information to any organization, regardless of which operating systems or applications are deployed, or
what backup system is in place.
880 pp., ISBN: 978-1-4200-6599-2, $69.95 / £44.99
Catalog no. AU6396, January 2009, 308 pp., Soft Cover,
ISBN: 978-1-4200-7639-4, $69.95 / £44.99
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Services, Technologies,
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Initiation Protocol
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COMMUNICATIONS WITH OPTICS, LASERS & PHOTONICS
Photonic
MEMS Devices
New!
Photoacoustic Imaging
and Spectroscopy
New!
Design, Fabrication and Control
Edited by
Ai-Qun Liu
Washington University, St. Louis, USA
Nanyang Technological University, Singapore
With a scope beyond traditional design and
analysis, Photonic MEMS Devices introduces
this new research field, covering all aspects of
engineering innovation, design, modeling, fabrication, control, and experimental implementation of devices.
Building on the existing body of literature, this book presents new
photonic MEMS approaches on the micro- and nanoscale.
504 pp., ISBN: 978-1-4200-4568-0, $129.95 / £82.00
Lihong Wang
Bringing together leading pioneers in the field
to write about their own work, Photoacoustic
Imaging and Spectroscopy provides a full
account of the latest research and developing
applications in the area of biomedical photoacoustics. Featuring 39 detailed and insightful chapters, this comprehensive volume provides a full review of photoacoustic,
optoacoustic, and thermoacoustic imaging.
Catalog no. 59912, March 2009
518 pp., ISBN: 978-1-4200-5991-5, $149.95 / £89.00
New!
Practical Applications
of Microresonators in
Optics and Photonics
Andrey Matsko
New!
Digital Optical
Communications
Independent Contractor, Pasadena, California, USA
Le Nguyen Binh
This book reports on the progress in the rapidly growing field of monolithic micro- and nano-resonators. It
opens with a chapter on photonic crystal-based resonators
(nanocavities) and then goes on to describe resonators in which
the closed trajectories of light are supported by any variety of total
internal reflection in curved and polygonal transparent dielectric
structures. A portion of coverage is dedicated to the unique properties of resonators.
Monash University, Clayton, Victoria, Australia
585 pp., ISBN: 978-1-4200-6578-7, $149.95 / £89.00
Optoelectronics
After reviewing the fundamentals of modern
communications, specifically high-speed optical communications, this text explores the field’s practical applications. The author minimizes unwieldy mathematical analysis
and instead emphasizes operating principles. Supplemented
with case studies and examples, the book presents the theoretical foundations and technical developments that are continually
leading to faster and faster transmissions.
580 pp., ISBN: 978-1-4200-8205-0, $119.95 / £44.99
New!
New!
Infrared-Visable-Ultraviolet Devices
and Applications, Second Edition
Slow Light
Edited by
Science and Applications
Dave Birtalan
Edited by
OPTEK Technology, Carrollton, Texas, USA
Jacob B. Khurgin
William Nunley
John Hopkins University, Baltimore, Maryland, USA
Technical Consultant, (retired from TRW Inc.)
Richardson, Texas, USA
Rodney S.Tucker
Fully revised to reflect current developments, Optoelectronics:
Infrared-Visible-Ultraviolet Devices and Applications, Second
Edition reviews relevant semiconductor fundamentals, including
device physics, from an optoelectronic industry perspective. This
easy-reading text provides a practical engineering introduction to
optoelectronic LEDs and silicon sensor technology for the infrared,
visible, and ultraviolet portion of the electromagnetic spectrum.
Reflecting up-to-date research, this book presents a comprehensive introduction to slow
light and its potential applications. Leading authorities in fields as
diverse as atomic vapor spectroscopy, fiber amplifiers, and integrated optics provide an interdisciplinary perspective. Each section addresses slow light in a different medium, namely atomic
media, semiconductors, fibers, and photonic structures.
Catalog no. 6780X, April 2009
300 pp., ISBN: 978-1-4200-6780-4, $149.95 / £89.00
404 pp., ISBN: 978-1-4200-6151-2, $139.95 / £89.00
University of Melbourne, Victoria, Australia
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CIRCUITS & SIGNALS
New!
New!
The Circuits and
Filters Handbook,
Third Edition
Circuits at the Nanoscale
Five-Volume Set
Edited by
Edited by
Krzysztof Iniewski
Wai-Kai Chen
CMOS Emerging Technologies Inc., Vancouver,
British Columbia, Canada
Communications, Imaging,
and Sensing
Retired, Freemont, California, USA
This third edition of the groundbreaking bestseller surveys current accomplishments in the field. All five volumes have been
extensively updated to provide the most current information
available in the emerging fields of circuits and filters, both analog and digital. With contributions from more than 150 leading
international experts, this reference includes the key mathematical formulas, concepts, definitions, and derivatives that those
involved with cutting-edge research and design require. It
avoids extensively detailed theory to concentrate on professional applications with numerous examples provided throughout.
The set includes more than 2500 illustrations and hundreds of
references. Available as a five-volume set, each subject-specific
volume can also be purchased separately.
Catalog no. 55275, April 2009
c. 3150 pp., ISBN: 978-1-4200-5527-6, $199.95 / £121.00
Written by top-notch experts, Circuits at the Nanoscale:
Communications, Imaging, and Sensing addresses the state
of the art in CMOS circuit design in the context of system opportunities. This book explores materials such as SiGe, carbon nanotubes, and quantum dots that can potentially take system performance beyond traditional CMOS. Because CMOS circuit
implementation is key to understanding emerging technologies,
several chapters focus on this area, including low power circuit
implementations for microprocessor applications and circuit
implementations for biomedical space. The text also discusses
such topics as digital radio processing for wireless communications and circuits for medical imaging.
602 pp., ISBN: 978-1-4200-7062-0, $149.95 / £95.00
Embedded Systems Handbook,
Second Edition
New!
Two-Volume Set
Edited by
Richard Zurawski
New!
ISA Corporation, San Francisco, California, USA
Comprised of 48 chapters and the contributions of 74 leading
experts from industry and academia, this second edition of a
bestseller presents a comprehensive view of embedded systems:
their design, verification, networking, and applications. The contributors, directly involved in the creation and evolution of the
ideas and technologies presented, offer tutorials, research surveys, and technology overviews, exploring new developments,
deployments, and trends.
Volume I: Embedded Systems Design
and Verification
Catalog no. K10385, July 2009
c. 636 pp., ISBN: 978-1-4398-0755-2, $99.95 / £60.99
Volume II: Network Embedded Systems
Catalog no. K10386, July 2009
c. 808 pp., ISBN: 978-1-4398-0761-3, $99.95 / £60.99
Order the set and save!
Catalog no. 74105, July 2009
c. 1352 pp., ISBN: 978-1-4200-7410-9, $149.95 / £89.00
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2-D Electromagnetic
Simulation of Passive
Microstrip Circuits
Alejandro Dueñas Jiménez
Universidad de Guadalajara, Jalisco, Mexico
A reference for circuit design engineers and microwave engineers, this book covers the subject in a style that is useful to
both. It uses a simple 2-D electromagnetic simulation procedure
to provide basic knowledge and practical insight into quotidian
problems of microstrip passive circuits applied to microwave
systems and digital technologies. The author’s approach follows
a natural route starting from analysis of the test circuits, continuing with de simulation and finishing with the measurement. At
the end of the book some typical problems of signal integrity
such as ringing and overshooting are stated and solved by using
knowledge acquired thoughout the book.
288 pp., ISBN: 978-1-4200-8705-5, $139.95 / £89.00
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CIRCUITS & SIGNALS
Sensor Array Signal
Processing
New!
Networks-on-Chips
Theory and Practice
Edited by
Fayez Gebali, Haytham Elmiligi, &
Mohamed Watheq El-Kharashi
University of Victoria, British Columbia, Canada
Addressing the challenging topics related to
NoC research, this book highlights traffic modeling, including
the details of traffic generators. It describes the steps involved in
the design of traffic generation environment. Then, as an example, an MPEG environment is presented. It includes coverage of
implementation issues using case studies and examples.
389 pp., ISBN: 978-1-4200-7978-4, $99.95 / £60.99
Second Edition
Prabhakar S. Naidu
Indian Institute of Science, Bangalore
Fully updated and expanded, the second edition of this popular text covers the wide
range of interrelated topics in array processing. It adds chapters focusing on the use of
antenna arrays in wireless communications
and on localization. It also adds coverage of multi-component
sensors, space-time processing, Azimuth/elevation estimation,
and frequency invariant beamformation. Each concept is
described in precise mathematical language.
Catalog no. 71904, June 2009
c. 556 pp., ISBN: 978-1-4200-7190-0, $119.95 / £72.99
Brief Notes in
Advanced DSP
New!
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Fourier Analysis with MATLAB®
Signals, Systems, Transforms,
and Digital Signal Processing
with MATLAB®
Artyom M. Grigoryan
Michael Corinthios
Based on the authors’ research, this text
addresses many concepts and applications of
DSP. The book describes the discrete Fourier transform, lifting
schemes, integer transforms, the discrete cosine transform, and the
discrete Hadamard transform. It also examines the decomposition
of the 1-D signal by section basis signals as well as new forms of
the 2-D signal/image representation by direction signals/images.
MATLAB® codes illustrate how to apply the ideas in practice.
Ecole Polytechnique de Montreal, Canada
This book’s objective is simplification without comprise of rigor.
Graphics, physical interpretation of subtle mathematical concepts, and a gradual transition from basic to more advanced topics are meant to be among the important contributions of this
book. It establishes a solid background in Fourier, Laplace, and
z transforms, before extending them in later chapters. The
author offers extensive referencing to MATLAB® and
Mathematica® for solving the examples.
c. 1256 pp., ISBN: 978-1-4200-9048-2, $129.95 / £78.99
Radar Signal Analysis and
Processing Using MATLAB®
University of Texas, San Antonio, USA
Merughan Grigoryan,
Yerevan, Armenia
Catalog no. K10088, February 2009
354 pp., ISBN: 978-1-4398-0137-6, $99.95 / £60.99
RFID Handbook
Applications, Technology,
Security, and Privacy
Edited by
Syed A.Ahson
Bassem R. Mahafza
Motorola, Plantation, Florida, USA
deciBel Research Inc., Huntsville, Alabama, USA
Mohammad Ilyas
Offering radar-related software for the analysis and design of radar waveform and signal
processing, this book provides comprehensive coverage of radar signals, signal processing techniques, and algorithms. It contains
numerous graphical plots, common radarrelated functions, table format outputs, and end-of-chapter
problems. The complete set of MATLAB® functions and routines
are available for download online.
Catalog no. C6643, 2008
504 pp., ISBN: 978-1-4200-6643-2, $99.95 / £63.99
From basic concepts to future research directions, the RFID Handbook covers all aspects
of RFID technology. It presents current and emerging applications
in supply chain management, field reporting and communication
systems, the pharmaceutical industry, video surveillance, and
information services. It also describes various technologies from
data management systems to transient and persistent electronic
product codes.
Catalog no. 54996, 2008
712 pp., ISBN: 978-1-4200-5499-6, $139.95 / £89.00
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ELECTROMAGNETICS
New!
Surface Impedance
Boundary Conditions
A Comprehensive Approach
Numerical Techniques
in Electromagnetics
with MATLAB®
Sergey V.Yuferev
Nokia Inc, Tampere, Finland
Nathan Ida
Third Edition
The University of Akron, Ohio, USA
Matthew N.O. Sadiku
Prairie View A&M University, Texas, USA
Continuing in the tradition of the bestselling first edition, the
third edition demonstrates how to pose, numerically analyze,
and solve electromagnetic problems (EM). Significant updates
include the transition of all FORTRAN code into the more widely used MATLAB® format as well as improvements made to the
standard algorithm for the finite difference time domain (FDTD)
method and the treatment of absorbing boundary conditions in
FDTD, the finite element method, and the transmission-linematrix method. In addition to updated examples and new
homework problems throughout, the second edition adds a
chapter on the method of lines. An appendix covers use of MATLAB code. A solution manual is available upon qualifying course
adoption.
Catalog no. 6309X, April 2009
648 pp., ISBN: 978-1-4200-6309-7, $119.95 / £49.99
Please visit www.crcpress.com
for more information and
complete tables of contents
Metamaterials Handbook
Two Volume Slipcase Set
New!
Filippo Capolino
University of Houston, Texas, USA
From microwave to optical ranges, the Metamaterials
Handbook covers all aspects in the field of metamaterials in
two separate volumes. Volume I provides background material
on phenomena and theory, while Volume II presents a wide
range of applications. Each subject is presented in a review format along with numerous references and end-of-chapter conclusions. This complete reference text addresses topics related to
both theory and application, including tunable metamaterials,
fabrication and characterization techniques for optical metamaterials, modeling, design, nonlinear metamaterials, as well as
applications in the microwave, millimeter wave, optical, and
THz frequency ranges.
c. 1600 pp., ISBN: 978-1-4200-5362-3, $169.95 / £103.00
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Taking the mystery out of surface impedance boundary conditions (SIBCs), this book provides an understanding of the subject that helps practitioners to select, use, and develop SIBCs for
their own applications. The authors take a comprehensive
approach and provide simple decision tools that allow readers
to decide if and how an SIBC can be used.
Catalog no. 44893, August 2009
c. 420 pp., ISBN: 978-1-4200-4489-8, $129.95 / £82.00
Ionosphere and
Applied Aspects of Radio
Communication and Radar
Nathan Blaunstein
Ben-Gurion University of the Negev, Beer Sheva, Israel
Eugeniu Plohotniuc
Universitatea de Stat "Alecu Russo" din Balti, Moldova
This book describes the main aspects of radio
propagation due to different natural and manmade phenomena occurring in ionospheric plasma, discusses stable radio communication links based on local scattering at natural
plasma inhomogeneities, and explains how inhomogeneities create focusing effects and can capture and channel radio waves in
the ionosphere-ground surface waveguides and then transmit
information over long distances.
600 pp., ISBN: 978-1-4200-5514-6, $149.95 / £95.00
RF and Microwave
Handbook
Second Edition,
Three Volume Set
Edited by
Mike Golio and Janet Golio
HVVi Semiconductors, Inc.,
Phoenix, Arizona, USA
The second edition of this bestseller divides its coverage conveniently into a set of three books, each focused on a particular
aspect of the technology. Six new chapters cover WiMAX, broadband cable, bit error ratio (BER) testing, high-power PAs (power
amplifiers), heterojunction bipolar transistors (HBTs), as well as an
overview of microwave engineering.
Catalog no. 7217, 2008
2208 pp., ISBN: 978-0-8493-7217-9, $179.95 / £114.00
www.crcpress.com
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COMPUTER ENGINEERING
New!
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Grid Computing
Infrastructure, Service, and
Applications
Lizhe Wang
Rochester Institute of Technology, USA
Wei Jie
University of Manchester, UK
ARM Assembly Language
Fundamentals and Techniques
William Hohl
ARM, Inc, Austin, Texas
Of the 13 billion microprocessor-based chips shipped last year,
nearly 3 billion were ARM-based. Since 1994, ARM has introduced five new generations of processors; however, instruction
on compiling for 32 bit machines lags behind. Written for those
with some background in digital logic and high-level programming, this work provides a text for new programmers and a reference for students and professionals. It focuses on what is needed to compile for ARM, details real assembly uses, and explores
situations that programmers will ultimately encounter. A fully
functional evaluation version of the RealView Microcontroller
Development Kit from Keil accompanies the text.
Jinjun Chen
Swinburne University of Technology, Melbourne, Australia
The field of grid computing has made rapid progress in the last
few years, developing and evolving in almost all key areas. A
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deal only with parts of grid computing, this one covers the
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experts, it covers important topics such as philosophy, middleware, architecture, services, and applications. It also includes
technical details to demonstrate how grid computing works in
the real world and contains large number of references and
technical reports.
Catalog no. 67664, April 2009
528 pp., ISBN: 978-1-4200-6766-8, $129.95 / £78.99
Features
• Presents text, diagrams, and training materials produced
by ARM
• Reviews computing systems in general, with a brief history
of ARM included in the discussion of RISC architecture
• Details load and store instructions, along with methods for
passing parameters to functions
• Covers all required arithmetic operations, including an
optional section on fractional notation
• Provides a summary of all of the Version 4T instructions
• Supplies a wide range of invaluable case studies and
examples
Contents abridged
An Overview of Computing Systems. The ARM7 TDMI
Programmer’s Model. First Programs. Assembler Rules &
Directives. Loads, Stores and Addressing. Constants and Literal
Pools. Logic and Arithmetic. Loops and Branches. Tables.
Subroutines and Stacks. Exception Handling. Memory-mapped
Peripherals. Thumb. Mixing C and Assembly. Appendix A: The
ARM v4T Instruction Set. Appendix B: Running Keil Tools.
Appendix C: ASCII character codes.
Catalog no. K10302, March 2009
371 pp., ISBN: 978-1-4398-0610-4, $79.95 / £48.99
The Computer Engineering
Handbook
Second Edition, Two Volume Set
Edited by
Vojin G. Oklobdzija
University of California, Davis, USA
After nearly six years as the field's leading reference, the second
edition of this award-winning handbook reemerges with completely updated content and a brand new format. The Computer
Engineering Handbook, Second Edition is now offered as a
set of two carefully focused books that together encompass all
aspects of the field. In addition to complete updates throughout
the book to reflect recent issues in low-power design, embedded
processors, and new standards, this edition includes a new section on computer memory and storage as well as several new
chapters on such topics as semiconductor memory circuits, stream
and wireless processors, and nonvolatile memory technologies
and applications.
Catalog no. 3860, 2008
1648 pp., ISBN: 978-0-8493-8600-8, $159.95 / £99.00
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Advanced Linear Algebra for
Engineers with MATLAB®
Sohail A. Dianat & Eli S. Saber
Rochester Institute of Technology, New York, USA
Designed to Elevate Analytical and Problem-Solving Skills
This text provides systematic instruction that
allows engineers and engineering students to
make full use of the advanced capacities that
MATLAB® provides. Offering a broad selection
of progressive exercises and MATLAB® problems, each chapter features carefully chosen
examples that demonstrate underlying ideas at
work in practical scenarios.
Catalog no. 95234, February 2009
346 pp., ISBN: 978-1-4200-9523-4,
$99.95 / £49.99
New!
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• Provides a comprehensive and practical approach to
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• Presents theoretical explanations and corresponding
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• Demonstrates underlying ideas using carefully
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A solutions manual is available upon
qualifying course adoption
Practical Matlab® for Engineers,
Two-Volume Set
Save o
Misza Kalechman
City University of New York, Brooklyn, USA
on
the Set!
A Comprehensive and Accessible Primer
This two-volume tutorial immerses engineers and
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immediate use.
The first volume, Practical Matlab® Basics for
Engineers (Catalog no. 47744), covers functions, algebra, geometry, arrays, vectors, matrices,
trigonometry, graphs, pre-calculus, and calculus. It
then delves into the Matlab® language, covering
syntax rules, notation, operations, computational
programming, and general problem solving in the
areas of applied mathematics and general physics.
The second volume, Practical Matlab®
Applications for Engineers (Catalog no.
47760), illustrates the direct connection between
theory and real applications. Each chapter reviews
basic concepts and then explores those concepts
with a number of worked out examples.
Catalog no. 47736, January 2009, 900 pp.
Soft Cover, ISBN: 978-1-4200-4773-8, $129.95 / £82.00
New!
Standards, Conformity Assessment,
and Accreditation for Engineers
Robert D. Hunter
Robert D. Hunter Associates, Austin, Texas, USA
Presents Standards at the International, Regional, National, State,
and Company Levels
Features
Providing the tools needed to easily understand
and comply with new standards, this accessible • Covers economic, trade, legal, government, and
management aspects
resource not only addresses the technical areas of
standardization, but also the legal, economic, man- • Includes little known historical background on
several selected topics
agement, and educational aspects. It covers
required vocabulary and gathers references from • Provides website and literature references on organizations and their methods of standards development
the substantial yet scattered literature on standards.
Catalog no. K10074, February 2009, 232 pp.,
Soft Cover, ISBN: 978-1-4398-0094-2, $139.95 / £85.00
______________________
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CERTIFICATION CORNER
WARM WELCOMES
BY ROLF FRANTZ
In mid-March, I had the opportunity
to give a presentation on the Wireless
Communication Engineering Technologies (WCET) certification program at
the International Wireless Communications Expo (IWCE). This large conference (over 355 exhibitors) focuses
specifically on enterprise users of wireless communications, with a particular
emphasis also on the public safety
arena, where reliable wireless communications can literally be a matter of life
and death.
The warm reception from the conference organizers was appreciated, as
was the welcome and interest shown by
the attendees. A good crowd attended
my presentation, and a number of
them stayed afterward to ask questions
about the program. The high level of
interest was particularly evident at the
ComSoc booth on the exhibit floor,
where a steady stream of people
stopped by to learn more about WCET
certification. While it would be an
exaggeration to say that copies of the
2009 Candidate’s Handbook were “flying off the shelves,” our supply was
greatly reduced by the time the exhibits
closed. Many people also took copies
of WCET fliers that included the
announcement that the Wireless Engineering Body of Knowledge (WEBOK)
was available for pre-publication
orders. (It’s now in print; order your
copy through our website, www.ieee_______
wcet.org).
______ Dozens of people dropped
their business cards in the basket for
our raffle to give away a couple of free
Practice Exams (valued at $75, and an
ideal tool for determining one’s readiness to take the WCET certification
examination). And representatives of
three educational/training organizations inquired about how they might
go about setting up programs that
would help people prepare for the certification exam.
Adding to the warmth of the welcome was a conversation with the show
organizers during which we discussed
the possibility of IEEE ComSoc participating at IWCE next year with some
WCET-specific programming. We’re
looking at several possibilities, which
would focus on the technical content of
the WCET exam rather than on the
structure and administration of the
WCET program. Stay tuned for more
details on this as the plans begin to firm
up for next year.
A similar warm welcome was
reported by Celia Desmond, WCET
Program Director, after her visits with
various companies during the CTIA
Wireless 2009 event at the beginning
of April. In addition to the numerous
companies that expressed interest in
certification for their employees, several organizations (as at IWCE) indicated a desire to develop some
WCET-specific training courses to
help people prepare for the exam. A
number of companies also indicated
their future interest in WCET certification, once the economic outlook
improves.
Celia also reported that she was
warmly welcomed at IEEE’s Wireless
Communications and Networking Conference, where there was particular
interest in providing training programs
for people who want such help in
preparing for the exam. In addition to
the people who are planning to take the
exam (and others who are looking into
it), Celia reported that up to a half
dozen attendees approached her specifically to discuss the creation of training
courses. Given this training interest at
all three conferences, we hope to soon
add a number of organizations to the
list of known WCET training providers
at our website.
Our WCET team will continue to
visit industry events, to inform the
attendees about WCET certification,
answer their questions, and offer additional chances to win free Practice
Exams. The best way to find out where
we’ll be and when is to sign up for the
bi-monthly e-newsletter, IEEE Wireless
Communications Professional. You can
sign up — and learn much more about
the WCET program — by visiting our
website at www.ieee-wcet.org
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SERIES EDITORIAL
OPTICAL COMMUNICATIONS:
THE HIGHWAYS OF THE FUTURE
Hideo Kuwahara
I
Jim Theodoras
n the wake of OFC/NFOEC 2009, the year ahead
comes more clearly into focus. On the business front,
while economic uncertainty continues, and some companies traded their exhibit booths for corporate pavilions,
optical communications revenue continues to flow. A
commonly discussed topic at the show was the perceived
need for optical component suppliers to consolidate, the
theory being that most revenue comes from a few behemoths, and they only want to purchase from a select few
mega-suppliers who have complete product portfolios.
Another somewhat contradictory theory discussed suggested vertically integrated equipment providers have an
edge over those who shop at mega-suppliers rather than
develop technology in house. The skill of the technical
connoisseur is becoming more important. The one thing
everyone did agree on was that margins were being
squeezed from both the top and bottom, making profits
harder to realize.
On the technology front, there was a mix of both old
and new. Older technologies were refreshed with “oneupmanship,” as reconfigurable optical add-drop multiplexers (ROADMs) increased in degree, tunable lasers got
smaller, and transmission systems went farther. As is usual
at OFC, several heroic experiments were reported pursuing capacity, distance, and, recently, frequency efficiency.
Yet another module MSA was launched, this time a 100G
brick that may soon be relegated to paperweight status, as
technology continues to relentlessly march forward. The
leading Indium Phosphide (InP) photonic integrated circuit (PIC) has gotten bigger, yet again. However, the big
news in PICs was the extension of the term to include
more than just InP technologies, which brings us to the
new. Silicon photonics, and PICs based on them, looked
stunning this year. Perhaps the margin squeeze has had the
beneficial side-effect of forcing researchers to look for
ways of leveraging fabrication processes that have already
descended the cost curve, and silicon definitely fits the
need. Even pigtailed transceivers have made somewhat of
a comeback, as they can be made much more cheaply since
an extra connector and production ferrule alignment are
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Communications
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avoided, although they are now known as “active cables”
to give a new marketing spin to an old idea. At the intersection of 40/100G, PIC, and transceiver technologies were
a rash of new quad small form-factor pluggable (QSFP)
offerings for everything from Infiniband to Fibre Channel.
However, the most discussed topic hands down was political: the broadband portion of various economic stimulus
packages.
While the details of any broadband stimulus package
are beyond the scope of this editorial, the key takeaway
here is that the public now considers their virtual Internet
connectivity as crucial as their physical transportation connectivity. Let’s face it: a broadband connection does not
provide food, shelter, clothing, or transportation, and you
cannot eat, drink, breathe, or drive it. Yet broadband is
spoken in the same breath as these Maslowian needs. This
can only bode well for optical communications in the long
run. Just as the railroads of the late 1800s, highways of the
1950s, and airports of the 1960s led to continual economic
growth, so will optical communications of the 2000s. Optical communications has become the global highway system
of the future, and an engine of future economic growth.
Nevertheless, a big concern in its construction includes a
workable business model, a supporting legal system, and,
last but not least, the energy consumption of such a massive infrastructure and how green technologies might be
leveraged.
Let’s consider for a moment what would happen if
broadband Nirvana did occur. Global networks would
explode in size and bandwidth, and it is doubtful current networks could handle the additional burden. The
key to making larger networks of the future function
properly is higher-level protocols. For, as anyone who
has tried to sync their PDA to their computer knows,
protocols are an important piece of communications. In
this issue of the Optical Communications Series, we
take a step back and look at the bigger picture. The
articles we have chosen for this month examine the
higher-level protocols that are desperately needed as
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Minimize Your Design –
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Two new receiver families are being offered supporting the
design of next-generation 40 Gbit/s systems, reducing your
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SERIES EDITORIAL
bandwidth continues its climb to the stratosphere.
These proposals are not merely theoretical postulating,
though, as the concepts presented herein are validated
in real-world networks.
As a brief introduction, in alphabetical order, Azodolmolky et al. present a novel framework that addresses
dynamic cross-layer network planning and optimization
while considering the development of a future transport
network infrastructure, using DICONET in their study.
Callegati et al. propose to add a Session Initiation Protocol control layer to an optical burst switching network in
order to close the gap between application requests and
network control, using a real-life SIP-OBS testbed created through the integration of existing SIP-M and OBS
testbeds. Gagnaire discusses impairment-aware routing
and wavelength allocation (IA-RWA) in translucent networks, using NSFNET for analysis. Maier et al. discuss
the evolution of control-plane-enabled optical networking
toward multidomain integration through seamless interworking of different control planes by means of automatically switched optical network/generalized multiprotocol
label switching (ASON/GMPLS) and standardized network interfaces, using MUPBED for reference. Finally,
Skorin-Kapov et al. discuss failure management issues in
transparent optical networks and propose applying structural properties of self-organizing systems to create a
hybrid supervisory plane, using COST Action 266 for
analysis.
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BIOGRAPHIES
HIDEO KUWAHARA [F] (kuwahara.hideo@jp.fujitsu.com)
_________________ joined Fujitsu in 1974,
and has been engaged for more than 30 years in R&D of optical communications technologies, including high-speed TDM systems, coherent optical transmission systems, EDFA, terrestrial and submarine WDM systems, and related
optical components. His current responsibility is to lead photonics technology
as a Fellow of Fujitsu Laboratories Ltd. in Japan. He stayed in the United
States from 2000 to 2003 as a senior vice president at Fujitsu Network Communications, Inc., and Fujitsu Laboratories of America, Richardson, Texas. He
belongs to LEOS and ComSoc. He is a co-Editor of IEEE Communications Magazine’s Optical Communications Series. He is currently a member of the International Advisory Committee of the European Conference on Optical
Communications, and chairs the Steering Committee of CLEO Pacific Rim. He
is a Fellow of the Institute of Electronics, Information and Communications
Engineers (IEICE) of Japan. He has co-chaired several conferences, including
Optoelectronics and Communications Conference (OECC) 2007. He received an
Achievement Award from IEICE of Japan in 1998 for the experimental realization of optical terabit transmission. He received the Sakurai Memorial Award
from the Optoelectronic Industry and Technology Development Association of
Japan in 1990 for research on coherent optical communication.
JIM THEODORAS (jtheodoras@advaoptical.com)
_______________ is currently director of technical
marketing at ADVA Optical Networking, working on Optical + Ethernet transport products. He has over 20 years of industry experience in optical communication, spanning a wide range of diverse topics. Prior to ADVA, he was a senior
hardware manager and technical leader at Cisco Systems, where he managed
Ethernet switch development on the Catalyst series product. At Cisco, he also
worked on optical multiservice, switching, and transport products and related
technologies such as MEMs, electronic compensation, forward error correction,
and alternative modulation formats, and was fortunate enough to participate
in the “pluggable optics” revolution. Prior to acquisition by Cisco, he worked at
Monterey Networks, responsible for optics and 10G hardware development. He
also worked at Alcatel Networks during the buildup to the telecom bubble on
DWDM long-haul transport systems. Prior to DWDM and EDFAs, he worked at
Clarostat on sensors and controls, IMRA America on a wide range of research
topics from automotive LIDAR to femtosecond fiber lasers, and Texas Instruments on a variety of military electro-optical programs. He earned an M.S.E.E
from the University of Texas at Dallas and a B.S.E.E. from the University of Dayton. He has 15 patents granted or pending.
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A Dynamic Impairment-Aware
Networking Solution for Transparent
Mesh Optical Networks
Siamak Azodolmolky, Dimitrios Klonidis, and Ioannis Tomkos, AIT
Yabin Ye, Chava Vijaya Saradhi, and Elio Salvadori, Create-Net
Matthias Gunkel, Deutsche Telekom
Kostas Manousakis, Kyriakos Vlachos, and Emmanouel Manos Varvarigos, RACTI
Reza Nejabati and Dimitra Simeonidou, University of Essex
Michael Eiselt, ADVA AG Optical Networking
Jaume Comellas and Josep Solé-Pareta, Universitat Politècnica de Catalunya
Christian Simonneau and Dominique Bayart, Alcatel-Lucent Bell Labs France
Dimitri Staessens, Didier Colle, and Mario Pickavet, Ghent University — IBBT
ABSTRACT
Core networks of the future will have a
translucent and eventually transparent optical
structure. Ultra-high-speed end-to-end connectivity with high quality of service and high reliability
will be realized through the exploitation of optimized protocols and lightpath routing algorithms.
These algorithms will complement a flexible control and management plane integrated in the
proposed solution. Physical layer impairments
and optical performance are monitored and
incorporated in impairment-aware lightpath routing algorithms. These algorithms will be integrated into a novel dynamic network planning tool
that will consider dynamic traffic characteristics,
a reconfigurable optical layer, and varying physical impairment and component characteristics.
The network planning tool along with extended
control planes will make it possible to realize the
vision of optical transparency. This article presents a novel framework that addresses dynamic
cross-layer network planning and optimization
while considering the development of a future
transport network infrastructure.
INTRODUCTION
Increasing traffic volume due to the introduction
of emerging broadband services and bandwidth
demanding applications with different quality of
service (QoS) requirements are driving carriers
to search for a cost-effective core optical networking architecture that is tailored to the new
Internet traffic characteristics. The optical net-
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0163-6804/09/$25.00 © 2009 IEEE
work evolution and migration should aim at
improved cost economics, reduced operations
efforts, scalability, and adaptation to future services and application requirements. The main
drivers for this migration are:
• Requirement for high bandwidth and endto-end QoS-guaranteed connectivity
• On demand (dynamic) technology-independent service provisioning
Optical network architectures can be characterized as either opaque, managed-reach, or alloptical (or transparent) networks (Fig. 1). In
opaque architectures the optical signal carrying
traffic undergoes an optical-electronic-optical
(OEO) conversion at every switching or routing
node in the network. The OEO conversion
enables the optical signal to reach long distances;
however, this is quite expensive due to the number of regenerators required in the network and
the dependence of conversion process on the
connection bit rate and modulation formats.
Transparent network architectures were proposed to reduce the associated cost of opaque
networks. In transparent networks the signals are
transported end-to-end optically, without any
OEO conversions along their path. In extended
networks physical signal impairments limit the
transparent reach distance, and in order to regenerate signal in the optical domain, all-optical
regenerators are required, but are not commercially available today. Managed reach (semitransparent, translucent, or optical-bypass) has
been proposed as a compromise between opaque
and transparent networks [1]. In this approach
selective regeneration is used at specific network
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O
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O
O
E
O
O
E
O
O
E
O
O
E
O
O
E
O
O
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O
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monitoring
equipment to reduce
O
E
O
the number of
O
E
O
redundant alarms
(a)
(b)
(c)
and to lower the
capital expenses,
(R)OADM/OXC
OEO regenerator
WDM link
and the design of
fast localization
Figure 1. Optical networks evolution: a) opaque everywhere; b) managed reach; c) all-optical.
algorithms are
among challenges of
locations in order to maintain the acceptable signal quality from source to destination.
All-optical core wavelength-division multiplexing (WDM) networks using reconfigurable
optical add/drop multiplexers (ROADMs) and
tunable lasers appear to be on the road toward
widespread deployment and could evolve to alloptical mesh networks based on optical crossconnects (OXCs) in the future. In order to
realize the vision of transparency while offering
efficient resource utilization and strict QoS guarantees based on certain service level agreements,
the core network should efficiently provide high
capacity, fast and flexible provisioning of links,
high reliability, and intelligent control and management functionalities. A very important aspect
is also a high degree of performance management at the transparent intermediate nodes to
enable fault localization in the case of a performance degradation of the optical channel.
The issues of core optical network planning
and operation have been recognized within the
Dynamic Impairment Constraint Networking for
Transparent Mesh Optical Networks
(DICONET) project. The DICONET project is
funded by the ICT program, European Commission, and contributes to the strategic objective
“The Network of the Future” by supporting
innovative networking solutions and technologies
for intelligent and transparent optical networks.
In this article the existing static network planning procedures are extended toward equivalent
ones for a flexible and dynamic networking
paradigm. After introducing the main challenges
involved in transparent optical networks, the
DICONET vision and objectives are presented
including physical layer modeling, optical performance and impairment monitoring schemes,
impairment-aware path computation, failure
localization, and control plane extensions.
TRANSPARENT OPTICAL NETWORK
CHALLENGES
transparent optical core networks is an important task that is required in order to provide cost
(capital and operating expenditures, CAPEX
and OPEX) reduction and performance benefits.
This goal has not yet been achieved in commercial exploitation due to:
• Limited system reach and overall transparent optical network performance
• Difficulties related to fault localization and
isolation in transparent optical networks
In transparent optical networks, as the signal
propagates in a transparent way, it experiences
the impact of a variety of quality degrading phenomena that are introduced by different types of
signal distortions. These impairments accumulate along the path, and limit the system reach
and overall network performance. There are distortions of almost “deterministic” type related
only to the pulse stream of a single channel,
such as self-phase modulation (SPM), group
velocity dispersion (GVD), or optical filtering.
The other category includes degradations having
a statistical nature such as amplified spontaneous emission (ASE) noise, WDM nonlinearities (four-wave mixing [FWM] and cross-phase
modulation [XPM]), polarization mode dispersion (PMD), and crosstalk (XT).
In a transparent optical network, the impact
of failures also propagates through the network
and therefore cannot be easily localized and isolated. The huge amount of information transported in optical networks makes rapid fault
localization and isolation a crucial requirement
for providing guaranteed QoS and bounded
unavailability times. The identification and location of failures in transparent optical networks is
complex due to three factors:
• Fault propagation
• Lack of digital information
• Large processing effort
The placement of monitoring equipment to
reduce the number of redundant alarms and
lower the CAPEX, and the design of fast localization algorithms are among challenges of fault
localization in transparent optical networks.
Optical transparency has an impact on network
design, by either putting some limits on the size
of WDM transparent domains in order to neglect
physical impact on quality of transmission (QoT)
or introducing physical considerations in the network planning process (e.g., extra rules for
WDM systems or performance monitoring). The
realization of dynamic and fully automated
The most commonly adopted approach to overcome the mentioned issues is utilization of optoelectronic regenerators on a per channel basis
on all (opaque architecture) or selected (managed-reach) optical nodes. A second approach
fault localization in
transparent optical
networks.
DICONET SOLUTION
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Network
management
system (NMS)
DICONET
Network planning/
operation tool
• Physical layer impairments modeling
• Optical performance and impairment monitoring
(OIM/OPM)
• IA-RWA (lightpath routing)
• Component (montiors + regenerators) placement
• Failure localization and resilience algorithms
• Multi-layer traffic engineering
• Control plane interfacing and integration
A
Network planner/Architect/manager
...
Operator
Control and/or management plane
Network planning tool
Edge routers and/or L2 switches
User interface
Edge routers and/or L2 switches
Physical
impairment
models
Optical transparent
network
Failure
localization
algorithms
Transponder
interface
(GbE, 10GbE,
STM-16,
STM-64,
STM-256
Impairment aware
lightpath routing
(IA-RWA algorithms)
Optical impairment/
Performance
monitoring
(OIM/OPM)
Data plane
(optical layer)
Figure 2. The DICONET solution: a) the DICONET vision; b) the DICONET network planning/operation tool.
uses impairment management techniques that
may be implemented optically (i.e., optical
means of impairment mitigation or compensation) or electronically at the optical transponder
interfaces (i.e., electronic impairment mitigation). In addition, specific routing and wavelength aassignment (RWA) algorithms are used
for lightpath routing while accounting for the
physical characteristics of lightpaths. We categorize this class of algorithms as impairment-aware
RWA (IA-RWA) algorithms. The vision of the
DICONET project (Fig. 2a) is that intelligence
in core optical networks should not be limited to
the functionalities that are positioned in the
management and control plane of the network,
but should be extended to the data plane on the
optical layer.
The key innovation of DICONET is the development of a dynamic network planning tool
residing in the core network nodes that incorporates real-time assessments of optical layer performance into IA-RWA algorithms and is
integrated into a unified control plane. In order
to realize the DICONET vision, several building
blocks should be considered in an orchestrated
fashion, which are briefly presented in the sequel.
PHYSICAL LAYER MODELING AND MONITORING
In order to realize the IA-RWA algorithms covered later in this section, physical impairments
should be carefully identified and modeled. Physical layer impairments may be classified as linear
and nonlinear. Linear impairments are independent of the signal power and affect each of the
optical channels (wavelengths) individually, while
nonlinear effects scale with optical power levels
and produce interdependencies of channels.
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The important linear impairments that should
be modeled and monitored are ASE, chromatic
dispersion (CD)/GVD, XT, filter cconcatenation
(FC), and PMD. Although also originating from
transmitter laser diodes, ASE noise is principally
brought by Erbium doped fiber amplifiers
(EDFAs) and degrades the optical-to-signal-noise
ratio (OSNR). CD or GVD is the impairment
due to which different spectral components of a
pulse (frequencies of light) travel at different
velocities. When uncompensated, CD limits the
maximum transmission reach and channel bit
rate. The effect of CD can be minimized using
dispersion compensation devices like dispersion
compensating fibers (DCFs), chirped fiber gratings (CFGs), or periodic filter devices (GiresTournois interferometers, etc.). XT (interchannel
and intrachannel) is the general term given to
the phenomenon by which signals from adjacent
wavelengths leak and interfere with the signal in
the actual wavelength channel. FC is produced
by signal propagation through multiple WDM
filters between source and destination, and
results mainly in the narrowing down the overall
filter pass-band. Finally, PMD manifests itself in
a difference of propagation velocities between
orthogonal polarizations (differential group
delay [DGD]), resulting in a broadening of the
signal pulses. The DGD is a statistical parameter
and evolves over time due to changes in stress
and temperature conditions on the optical fibers.
There are two categories of nonlinear effects.
The first arises due to the interaction of lightwaves with phonons (molecular vibrations) in
the silica medium. The two main effects in this
category are sstimulated Brillouin scattering
(SBS) and stimulated Raman scattering (SRS).
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Figure 3. Experimental setup and results: a) experimental testbed layout; b) measured OSNR vs. number of loops for several channels’
power.
The second set of nonlinear effects arises due to
the dependence of the refractive index on the
intensity of the applied electric field, which in
turn is proportional to the square of the field
amplitude. The effects in this category are SPM,
XPM, and FWM. References [2, 3] provide good
overall starting points.
For IA-RWA algorithms it is very important
to be able to accurately predict the performance
of the propagating channel considering all the
impairments that can degrade the signal quality
along the propagation. To establish an accurate
analytical model for our performance estimator
considering these impairments, an experimental
testbed that emulates a transparent mesh optical
network [4] will be used. It includes a recirculating loop with standard single mode fiber
(SSMF), LEAF fibers, and nodes with wavelength selective switching (WSS). In Fig. 3a the
section comprising SSMFs and WSS is displayed.
With this testbed it is possible to propagate the
channels several spans of SSMFs pass through a
node. This scenario can be repeated several
times before assessing the quality of the signal at
the reception side. For this setup 21 channels
were propagating, and we measured the central
channel (1550.12 nm). The bit rate was 10.709
GHz and the modulation format was non-return
to zero (NRZ). Odd and even channels are modulated by two modulators. Total power at the
input of the DCF was 10 dBm. Polarization of
odd and even channels is not controlled. Channel power at the input of each span is precisely
monitored. Figure 3b depicts the measurement
results for required OSNR for BER = 10–5 as a
function of distance and channel power. Number
of channels and EDFA output power have been
kept constant.
In addition to analytical and simulation techniques for modeling these impairments, monitoring techniques are required for measurements,
which finally enable the IA-RWA mechanism.
The monitoring could be implemented on the
impairment level (optical impairment monitoring
[OIM]) or at the aggregate level where the over-
all performance is monitored (optical performance monitoring [OPM]) [4].
The development of a physical layer modeling and monitoring scheme will provide the
intelligence to the DICONET platform to:
• Implement novel impairment-aware lightpath routing (i.e., IA-RWA) schemes
• Implement failure localization methods of
single and multiple failures in transparent
optical networks
• Construct and control complex network
topologies while maintaining a high QoS
and fulfillment of service level agreements
IMPAIRMENT-AWARE LIGHTPATH ROUTING
Besides routing a path from source to destination, in optical networks the wavelength of the
path should also be determined. The resulting
problem is referred to in literature as the RWA
problem, which is known to be NP-complete [5].
In most RWA proposals the optical layer is
considered a perfect medium; therefore, all outcomes of the RWA algorithms are considered
valid and feasible even though the performance
might be unacceptable. The incorporation of
physical impairments in transparent optical network planning problems has recently received
some attention from the research communities.
We can classify impairment-aware algorithms
into two main categories:
• Those that consider separately the RWA
problem and the effects of impairments
• Those that solve the RWA problem including impairment constraints in the problem
formulation
In the literature several variations to the first
case have been proposed. In the DICONET project, apart from this approach, we also plan to
examine the feasibility and applicability of algorithms belonging to the second case that jointly
consider the RWA problem and the impairment
constraints. The objective of the corresponding
joint optimization problem would be not only to
serve the connection requests using the available
wavelengths, but also to minimize the total accu-
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IA-RWA 1
IA-RWA 2
Blocking probability
0.25
0.2
0.15
0.1
0.05
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46
48
50
52
54
Number of available wavelengths
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58
60
Figure 4. Blocking probability vs. number of available wavelengths per link,
for Deutsche Telekom reference network and realistic traffic demand.
mulated signal degradation on the selected lightpaths.
The IA-RWA algorithms can also be classified as static and dynamic depending on whether
or not the impairments and overall network conditions are assumed to be time-dependent. Physical impairments may vary over time (i.e., dynamic
network conditions) and thus change the actual
physical topology characteristics. In the static
traffic case (aka offline) the optimization of all
connection requests can be performed, while in
the dynamic case (aka online), the optimization
of a single request has to be considered. Offline
RWA is known to be NP-complete. Making these
algorithms impairment-aware (IA-RWA) is even
more difficult; thus, various heuristics have been
proposed in the literature. However, the offline
algorithmic approaches proposed fail to formulate the interference among lightpaths. Moreover, when considering online traffic, the great
majority of algorithms proposed in the literature
only consider static network conditions (time
invariant impairments). IA-RWA algorithms in
the DICONET proposal try to address further
possible scenarios. In particular, the formulation
of the interference among lightpaths in offline
RWA is a significant problem from a theoretical
and practical perspective that will be carried
within the scope of DICONET. Regarding the
offline problem, in Fig. 4 the performance of two
impairment-aware algorithms (IA-RWA-1 and
IA-RWA-2) based on LP relaxation formulations
that model the interference among lightpaths as
additional constraints on RWA is compared to a
typical algorithm that solves the pure RWA
problem and considers impairments only in the
post-processing phase. The network topology
used was the DT optical network, using a realistic traffic scenario, and 10 Gb/s wavelengths. For
assessing the feasibility of lightpaths we used a Q
factor estimator that takes into account all the
most known impairments through detailed analytical models. The Q factor estimator takes as
input the lightpaths found by the algorithms, cal-
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culates the Q factor of all active lightpaths, and
returns how many of them have unacceptable
transmission quality. This graph shows that considering the impairments in RWA decisions leads
to better performance than an impairmentunaware approach. Also, the case in which
dynamic traffic demands may induce a different
impairment behavior is the most realistic situation for the dynamic network paradigm envisioned by the DICONET project. For this
scenario, apart from typical scalar algorithms, we
plan to examine multicost algorithms. In the multicost case the cost of a link is a vector, not a single cost value, with entries corresponding to
individual impairments (or a combination of
impairments). The real “cost” (in €, $, …) of a
path is also another important optimization
parameter for the IA-RWA algorithms.
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FAILURE LOCALIZATION
Failure management is one of the crucial functions
and a prerequisite for protection and restoration
schemes. All-optical components are not by design
able to comprehend signal modulation and coding;
therefore, intermediate switching nodes are unable
to regenerate data for all channels, making segment-by-segment testing of communication links
more challenging. As a direct consequence, failure
detection and localization using existing integrity
test methods are made more difficult.
In the DICONET framework an algorithm
that solves the multiple failures location problem
in transparent optical networks is proposed where
the failures are more deleterious and affect longer
distances. The proposed solution also covers the
non-ideal scenario, where lost and/or false alarms
may exist. Although the problem of locating multiple faults has been shown to be NP-complete,
even in the ideal scenario where no lost or false
alarms exist, the proposed algorithm keeps most
of its complexity in a precomputational phase.
Hence, the algorithm only deals with traversing a
binary tree when alarms are issued. This algorithm locates the failures based on received
alarms and the failure propagation properties,
which differ with the type of failure and the kind
of device that are in the network. Another algorithm has been proposed to correlate multiple
security failures locally at any node and discover
their tracks through the network. To identify the
origin and nature of the detected performance
degradation, the algorithm requires up-to-date
connection and monitoring information of any
established lightpath, on the input and output
side of each node in the network. This algorithm
mainly runs a localization procedure, which will
be initiated at the downstream node that first
detects serious performance degradation at an
arbitrary lightpath on its output side. Once the
origins of the detected failures have been localized, the network management system can then
make accurate decisions to achieve finer-grained
recovery switching actions.
In cases where efficient use of network capacity is important and restoration times on the
order of hundred(s) of milliseconds are acceptable, shared protection schemes are desirable.
However, as reported in [6], the CAPEX gain of
shared path protection compared to dedicated
path protection is much less in transparent opti-
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Control plane protocols
(e.g. OSPF-TE)
Path Computation Element
(PCE)
Local node/link
database
IA-RWA
algorithms
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Local node/link
database
(c)
(b)
framework an
algorithm that solves
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the multiple failures
location problem in
transparent optical
networks is proposed where the
failures are more
deleterious and
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OSPF-TE
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distances. The
proposed solution
TED
TED
also covers the non-
TED
ideal scenario, where
(a)
Figure 5. Control plane extensions: a) routing protocol extensions; b) signaling protocol extensions; c)
path computation element.
cal networks than the same metric in opaque
optical networks. Considering the dynamic network condition in IA-RWA algorithms and control plane integration make the fast response
time (50 ~ 100 ms) of the network operation
tool a key requirement for addressing the failure
recovery and resilience issues. Thus, dedicated 1
+ 1 protection, with one primary (i.e., working)
path and one backup (hot standby path), is clearly a good protection candidate. Two reference
networks, the Deutsche Telekom (DT) national
network and pan-European research network
(GEANT2), are selected for different studies.
Based on the characteristics of the DICONET
reference networks, we computed the link and
node disjoint shortest paths considering physical
layer impairments. On average, the protection
paths for the DT network and GEANT2 reference network are 46 and 37 percent longer than
their respective primary paths. We also observed
that the average hop count for primary and protection paths for both reference networks (DT
and GEANT2) are 46 and 30 percent more than
the hop counts of the working paths, respectively.
NETWORK PLANNING TOOL
The key innovation of DICONET is the development of a dynamic network planning tool
residing in the core network nodes that incorporates real-time measurements of optical layer
performance into IA-RWA algorithms and is
integrated into a unified control plane. As
depicted in Fig. 2b, this tool will integrate
advanced physical layer models with novel IARWA algorithms. It will serve as an integrated
framework that considers both physical layer
parameters and networking aspects, and will
optimize automated connection provisioning in
transparent optical networks.
The network planning tool has two operational modes:
• Offline mode
• Online (or real-time) mode
lost and/or false
alarms may exist.
The offline mode is selected in the planning
phase of a network. In this phase a full map of
network traffic and network conditions is fed
into the tool in order to produce the planning
outcomes. Since offline computation time is not
the main issue, optimization routines are allowed
to have high numerical complexity. The gained
results can be disseminated to the network management system, controlled by an operator. For
online use of the network planning tool, an
online traffic engineering solution is required
utilizing an interface between the control plane
and the management plane so that the network
situation could be evaluated in real time and its
results periodically disseminated into the network. In online mode this dynamic network
planning tool can be used to support optimum
network operation and engineering under
dynamically changing traffic and physical network conditions.
CONTROL PLANE EXTENSIONS
In order to realize an impairment-aware control
plane (impairment-aware light path routing,
topology and resource discovery, path computation, and signaling), existing protocols should be
extended properly. The extended control plane
will in turn address traffic engineering, resiliency, and QoS issues, and support automated and
rapid optical layer reconfiguration. The generalized multiprotocol label switching (GMPLS)
protocol suite [7] has gained significant momentum as a candidate for a unified control plane
[8]. Figure 5 shows three proposals to address
the integration of physical layer impairments
into the GMPLS control plane.
One direction deals with enhancement to the
interior gateway routing protocol (IGRP) (e.g.,
Open Shortest Path First with Traffic Engineering [OSPF-TE]), as shown in Fig. 5a. By flooding link state advertisements (LSAs) enhanced
with physical layer information, all nodes populate their traffic engineering database (TED)
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Using the
information of the
global topology
stored in the TED,
the PCE constructs a
reduced topology of
the network, based
on which the
IA-RWA algorithms
proceed to the path
computation taking
into account the
physical layer
parameters.
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with network-wide information, which can provide updated and accurate inputs to the IARWA algorithms. For a connection request, the
source node can interact with the TED to compute a proper route, taking into account the
physical layer information by using the IA-RWA
algorithms. Standard Resource Reservation Protocol with Traffic Engineering (RSVP-TE) is
used for lightpath establishment. We call this
approach the routing-based optical control plane
(R-OCP). This approach has some issues:
• TED inconsistency, scalability, and stability
when the link information changes very frequently [9]
• Requiring a powerful CPU at each node
and taking more time to solve the multiconstraint routing problem since not only the
network layer but also the physical layer
must be considered at the same time
• Difficulty in selecting unified mathematical
models for computing the effects of physical impairments since some of these models
are based on measurements and empirical
formulations
In the second approach, GMPLS signaling
(e.g., RSVP-TE) is extended to include physical
impairments information, as shown in Fig. 5b.
Routes from source to destination are dynamically computed using standard routing protocols
(e.g., OSPF-TE) without knowledge of the optical layer impairments. Only during the signaling
process does the enhanced RSVP-TE protocol
compute the amount of impairments along the
route; based on the results, the lightpath setup
request can be either accepted or rejected. Following this approach a local database in each
node (e.g., OXCs or ROADM) is required to
store the physical parameters that characterize
the node and its connected links without requiring full knowledge of physical layer information
of the whole network. We call this approach the
signaling-based optical control plane (S-OCP).
This approach can handle frequent changes of
optical parameters, and does not require global
flooding of physical impairments information,
thereby minimizing scalability problems. Due to
the lack of complex path computation algorithms, the load on the nodes’ CPUs is minimized. The main drawbacks of this approach are
longer path setup time due to the increased
number of setup attempts and possible suboptimal route decisions due to impairment-unaware
route computation algorithms.
In order to address the scalability requirements while maintaining TE support, path computation element (PCE) architecture is also
considered, as shown in Fig. 5c. The PCE can
reside within or external to a network node in
order to provide an optimal lightpath and interact with the control plane for establishment of
the proposed path. The PCE could represent a
local autonomous domain (AD) that acts as a
protocol listener to the intradomain routing protocols (e.g., OSPF-TE). Using the information
on global topology stored in the TED, the PCE
constructs a reduced topology of the network,
based on which the IA-RWA algorithms proceed
to path computation taking into account the
physical layer parameters.
The DICONET control plane uses extended
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GMPLS to facilitate IA-RWA and fault localization, which makes the software stack even more
complex than in standard GMPLS implementations. Therefore, to improve performance of the
control plane, DICONET will undertake a hardware implementation of some control protocol
procedures. The DICONET control plane is
implemented in reconfigurable hardware: field
programmable gate array (FPGA) and network
processors (NPs). To overcome complexity of
the control plane stack, only time-critical procedures of the DICONET control protocols are
implemented in the FPGA and NPs in the form
of a control protocol hardware accelerator.
The main control plane aspects addressed by
the DICONET relate to:
• Multilayer network control
• Routing and signaling-related mechanisms
and physical network characteristics information dissemination
• Design and implementation of a hardware
accelerator for impairment-aware forwarding and path selection
We have conducted preliminary studies on the
S-OCP and R-OCP approaches dealing with
static network conditions and dynamic traffic
where only linear impairments (loss, ASE, CD,
PMD, and XT) are considered; the mathematical models can be found in [9].
In the S-OCP approach, for a connection
request, the source node computes K explicit
routes. The signaling process starts checking the
optical feasibility of the first explicit route by
sending out a PATH message containing signal
properties information and a list of available
transmitters/wavelengths along the route. Upon
reception of the PATH message, each intermediate node updates these fields and checks the
wavelength availability. If there is no free wavelength on its outgoing link, the node sends a
PATH_ERR message toward the source node. If
the destination node receives the PATH message, it will evaluate the impairments, and check
for optical feasibility and a suitable transponder
for the connection request. If path establishment
is feasible, the destination node sends an RESV
message along the first explicit route to the
source node with a selected transponder pair;
otherwise, the destination node sends back a
PATH_ERR message. If the source node
receives a PATH_ERR message, it will send the
PATH message on the second explicit route and
repeat the process for the next route out of all K
routes.
In the R-OCP approach the source node will
compute K routes through the IA-RWA algorithm, which takes into account wavelength
availability as well as physical impairments. Once
the source node receives the specific wavelength
availability information per link, it can compute
the optical feasibility through its physical layer
module implementing the equations described in
[9]. The optically feasible computed path would
then be set up through standard RSVP-TE
selecting one of the available wavelengths
according to a First-Fit policy.
AT&T and Daisy networks (Figs. 6a and 6b)
have been used to evaluate the performance of
the S-OCP and R-OCP architectures. The maximum length of a Daisy network is 80 km. The
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60%
80%
100%
40%
60%
80%
100%
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Network load
(c)
(d)
Figure 6. Network topologies and blocking probability and path setup time performance: a) AT&T network topology; b) Daisy
network topology; c) blocking probability vs. network load for Daisy and AT&T networks; d) path setup time vs. network load for Daisy
and AT&T networks.
AT&T topology has been scaled down by a factor of 1:23. The purpose is to avoid in-line optical amplifiers in all fiber links, and only pre- and
booster optical amplifiers are used inside each
node. Several modifications/extensions are made
to RSVP-TE and OSPF-TE protocols on the
GMPLS Lightwave Agile Switching Simulator
(GLASS) [10]. The traffic and simulation scenarios used in the simulation experiments are same
as described in [9]. The simulation results have a
confidence level of 95 percent.
Figure 6c compares the blocking probability
of R-OCP and S-OCP architectures for AT&T
and Daisy networks. In the AT&T network, it
can be found that the blocking performance of SOCP architecture is very close to R-OCP. In the
Daisy network, the blocking performance of SOCP is slightly worse than R-OCP. Figure 6d
compares the average lightpath setup time of R-
OCP and S-OCP architectures for AT&T and
Daisy networks. Lightpath setup time is defined
as the elapsed simulation time between the first
PATH message sent and the RESV message
received at the source node. This metric reflects
how fast a connection request can be established.
It can be seen that, in general, the lightpath
setup time for R-OCP and S-OCP architectures
does not change much with traffic load. S-OCP
has the higher setup time, mainly because the
source node tries all K-explicit paths sequentially
until the lightpath is established or blocked.
SUMMARY
Transparent dynamic optical networks are the
next evolution step of translucent optical networks. Both of them have been recognized as
the evolution of static WDM networks. In order
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Solving these
challenges is the
main goal of the
DICONET project.
It is the vision of
DICONET that
intelligence in the
core optical
networks should not
be limited only to
certain functionalities
of control and
management planes,
but should also be
extended to the
physical layer.
to provide high-speed and QoS guaranteed connectivity with high reliability, considering the
realistic optical layer, the DICONET vision was
presented in this article as a disruptive and novel
solution for optical networking. Two main challenges of transparent networks are identified:
• Limited system reach and overall network
performance due to physical impairments
• Challenges related to failure localization
and isolation
Solving these challenges is the main goal of
the DICONET project. It is the vision of
DICONET that intelligence in the core optical
networks should not be limited only to certain
functionalities of control and management
planes, but also be extended to the physical
layer. Following this vision, the main physical
impairments as well as the essential role of optical performance and impairment monitoring
schemes, IA-RWA algorithms, and failure localization algorithms complemented with an impairment-aware control plane are discussed in this
article.
ACKNOWLEDGMENTS
The authors would like to thank the EC FP7DICONET (http://www.diconet.eu) project for
partly funding this work.
REFERENCES
[1] G. Shen and R. S. Tucker, “Translucent Optical Networks
The Way Forward,” IEEE Commun. Mag., vol. 45, no. 2,
Feb. 2007, pp. 48–54.
[2] R. Ramaswami and K. N. Sivarajan, Optical Networks —
A Practical Perspective, 2nd ed., Morgan Kaufmann,
2001.
[3] G. P. Agrawal, Nonlinear Fiber Optics, 3rd ed., Academic Press, 2001.
[4] P. Peloso et al., “Optical Transparency of a Heterogeneous Pan-European Network,” J. Lightwave Tech., vol.
22, no. 1, Jan. 2004, pp. 242–48.
[5] H. Zang, J. P. Jue, and B. Mukherjee, “A Review of
Routing and Wavelength Assignment Approaches for
Wavelength-Routed Optical WDM Networks,” Opt.
Net., vol. 1, Jan. 2000.
[6] D. Staessens et al., “Path Protection in WSXC Switched
Networks,” ECOC 2008, Brussels.
[7] E. Mannie, “Generalized Multiprotocol Label Switching
(GMPLS) Architecture,” IETF RFC 3945, Oct. 2004.
[8] A. Farrel and I. Bryskin, GMPLS: Architecture and Applications, Morgan Kaufman, 2005.
[9] E. Salvadori et al., “A Study of Connection Management Approaches for an Impairment-Aware Optical
Control Plane,” Proc. ONDM, May 2007, pp. 229–38.
[10] GMPLS Lightwave Agile Switching Simulator (GLASS);
http://snad.ncsl.nist.gov/glass/
ADDITIONAL READING
[1] D. C. Kilper et al., “Optical Performance Monitoring,” J.
Lightwave Tech., vol. 22, no. 1, Jan. 2004, pp. 294–304.
BIOGRAPHIES
S IAMAK A ZODOLMOLKY [S] (sazo@ait.edu.gr)
__________ received his
computer hardware (B.Eng.) degree from Tehran University
in 1994 and his M.Eng. in computer architecture from
Azad University in 1998. He worked with Data Processing
Iran during 1992–2001. He received his second M.Sc.
degree from Carnegie Mellon University in 2006. He joined
Athens Information Technology (AIT) as a researcher in
2007, while also pursuing a Ph.D. He is a professional
member of ACM.
DIMITRIOS KLONIDIS (dikl@ait.edu.gr)
________ is an assistant professor
at AIT. He was awarded his Ph.D. degree in the field of
optical communications and networking from the University of Essex, United Kingdom, in 2006. In September 2005
he joined the high-speed Networks and Optical Communi-
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cations (NOC) group in AIT as a faculty member and senior
researcher. He has several years of research and development experience, working on a large number of national
and European projects in the field of optical switching,
networking, and transmission. He has more than 50 publications in international journals and has refereed major
conferences. His main research interests are in the area of
optical communication networks, including optical transmission and modulation, signal processing and equalization, fast switching, and node control.
IOANNIS TOMKOS (itom@ait.edu.gr)
_________ is the associate dean of
AIT (since 2004), having the rank of full professor and
adjunct faculty at the Information Networking Institute of
Carnegie-Mellon University. At AIT he founded and serves
as head of the High Speed Networks and Optical Communication (NOC) Research Group that participates in many
EU funded research projects (including five running FP7
projects) in which he represents AIT as principal investigator and has a consortium-wide leading role (e.g., project
leader of the EU ICT STREP project DICONET, technical
manager of the EU IST STREP project TRIUMPH, chairman
of the EU COST 291 project, WP leader). He has received
the prestigious title of Distinguished Lecturer of IEEE Communications Society on the topic of transparent optical
networking. Together with his colleagues and students he
has co-authored over 75 peer-reviewed articles published
in international scientific journals, magazines, and books,
and over 175 presentations at conferences, workshops,
and other events. He has served the scientific community
as Chair of the International Optical Networking Technical
Committee of IEEE Communications Society and Chairman
of the IFIP Photonic Networking working group. He is currently Chairman of the OSA Technical Group on Optical
Communications. He has been General Chair, Technical
Program Chair, Subcommittee Chair, Symposium Chair,
and/or member of the steering/organizing committees for
major conferences (OFC, ECOC, IEEE GLOBECOM, IEEE ICC,
ONDM, etc.) in the area of telecommunications/networking
(more than 50 conferences/workshops). In addition, he is a
member of the Editorial Boards of the IEEE/OSA Journal of
Lightwave Technology, OSA Journal of Optical Networking,
IET Journal on Optoelectronics, and International Journal
on Telecommunications Management. His current work
focuses on optical communications/networking, network
planning, future Internet, and techno-economic studies of
broadband networks
Y A B I N Y E [M] (yabin.ye@create-net.org)
_______________ is a senior
researcher with European Research Center, Huawei Technologies Deutschland GmbH. He got his Ph.D. from
Tsinghua University, Beijing, China, in 2002. Before he
joined Huawei, he worked at the Institute for Infocomm
Research, Singapore, and Create-Net, Italy. His main
research includes optical networking and hybrid
optical/wireless communications
(saradhi.chava@create-net.org)
C HAVA V IJAYA S ARADHI ___________________
received his Ph.D. degree in electrical and computer engineering from National University of Singapore in 2007. He
was with Institute for Infocomm Research, Singapore, from
September 2002 to December 2006 as a senior research
engineer. Currently, he is working with Create-Net on several industrial and EU funded optical projects. He has over
50 journal/conference articles. He has served as a co-guest
editor of IEEE Communications Magazine and IEEE
Network.
ELIO SALVADORI (elio.salvadori@create-net.org)
_______________ graduated in
telecommunications engineering (Laurea) from the Politecnico di Milano, Italy, in 1997. From 1998 to 2001 he
worked as a network planner and technical sales engineer
in Nokia Networks and Lucent Technologies. In November
2001 he moved to the University of Trento, where he
received his Ph.D. degree in 2005. He then joined CREATENET and since January 2008 has been leading the Engineering Competence Center. He has authored a number of
publications in the area of traffic engineering for optical
networks, passive optical networks, and fixed broadband
wireless access systems.
MATTHIAS GUNKEL (GunkelM@telekom.de)
____________ received his Ph.D.
for studies on polarization control for coherent receivers
from Darmstadt Technical University in 1997. From 1997 to
1999 he was with Virtual Photonics, Berlin, before he
joined the Research Centre of Deutsche Telekom (DT),
Darmstadt, which was integrated into DT’s subsidiary TSystems. He was involved in IST NOBEL projects where he
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studied transmission impacts and limitations of transparent
network architectures. In 2008 he joined the Standardization group of DT.
K ONSTANTINOS M ANOUSAKIS (manousak@ceid.upatras.gr)
________________
received a Diploma degree from the Computer Engineering
and Informatics Department, University of Patras, Greece,
in 2004 and an M.Sc. degree in computer science and
engineering from the Computer Engineering and Informatics Department in 2007. He is currently a Ph.D. candidate
in the same department. His research activities focus on
optimization algorithms for high-speed and optical networks.
KYRIAKOS G. VLACHOS (kvlachos@ceid.upatras.gr)
______________ received his
Dipl.-Ing. degree in electrical and computer engineering
from the National Technical University of Athens (NTUA),
Greece, in 1998 and his Ph.D. in electrical and computer
engineering, also from NTUA, in 2001. Since 2005, He is a
faculty member with the Computer Engineering and Informatics Department of the University of Patras. His research
interests are in the areas of high-speed protocols and technologies for broadband, high-speed networks, optical
packet/burst switching, and grid networks. He is the coauthor of more than 90 journal and conference publications and holds five patents.
EMMANOUEL (MANOS) VARVARIGOS (manos@ceid.upatras.gr)
_____________
received a Diploma in electrical and computer engineering
from NTUA in 1988, and M.S. and Ph.D. degrees in electrical engineering and computer science from the Massachusetts Institute of Technology in 1990 and 1992,
respectively. He has held faculty positions at the University
of California, Santa Barbara (1992–1998, as an assistant
and later associate professor) and Delft University of Technology, the Netherlands (1998–2000, as an associate professor). In 2000 he became a professor with the
Department of Computer Engineering and Informatics at
the University of Patras, where he heads the Communication Networks Laboratory. He is also director of the Network Technologies Sector (NTS) at the Research Academic
Computer Technology Institute (RA-CTI). He has served on
the organizing and program committees of several international conferences, primarily in the networking area, and
national committees. He has also worked as a researcher at
Bell Communications Research, and has consulted with several companies in the United States and Europe. His
research activities are in the areas of high-speed networks,
protocols, network architectures, network services, and
parallel and grid computing.
REZA NEJABATI (rnejab@uessex.ac.uk)
___________ joined the University of
Essex in 2002 and is currently a member of the Photonic
Network Group there. For the last eight years he has
worked on ultra-high-speed optical networks, service-oriented and application-aware networks, network service virtualization, control and management of optical networks,
high-performance network architecture, and technologies
for e-science. He holds a Ph.D. in optical networks and an
M.Sc. with distinction in telecommunication and information systems
DIMITRA SIMEONIDOU (dsimeo@uessex.ac.uk)
____________ is head of the
Photonic Networks Group and the newly established High
Performance Networked Media Laboratory at the University
of Essex. She joined Essex in 1998 (previously with Alcatel
Submarine Networks). She is an active member of the optical networking and grid research communities, and participates in several national and European projects and
initiatives. Her main areas of research are photonic switching, ultra high-speed network technologies and architectures, control and service plane technologies for photonic
networks, and architectural considerations for photonic
grid networks. She is the author and co-author of over 250
papers, 11 patents, and several standardization documents.
MICHAEL EISELT (meiselt@advaoptical.com)
______________ received his Dipl.Ing. degree in electronics from the University of Hannover
in 1989 and his Ph.D. (Dr.-Ing.) in photonics from the
Technical University of Berlin in 1994. During his 20-year
career in optical communications, he has worked at various
companies and research organizations in Germany and the
United States. As director of Advanced Technology at
ADVA Optical Networking, Germany, he is currently directing and performing physical layer research in various projects, among them the German 100GET-METRO and
European DICONET projects.
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J AUME C OMELLAS (comellas@tsc.upc.edu)
_____________ received M.S
(1993) and Ph.D. (1999) degrees in Telecommunications
Engineering from UPC. His current research interests are
optical transmission and IP over WDM networking topics.
He has participated in many research projects funded by
the Spanish government and the European Commission.
He has co-authored more than 70 research articles in international journals and conferences. He is associate professor
at the Signal Theory and Communications Department of
UPC.
JOSEP SOLÉ-PARETA (pareta@ac.upc.edu)
__________ obtained his M.Sc.
degree in telecommunications engineering in 1984, and his
Ph.D. in computer science in 1991, both from the Polytechnic University of Catalonia (UPC). In 1984 he joined the
Computer Architecture Department of UPC. Currently he is
a full professor with this department. He did a postdoctoral stage (summers of 1993 and 1994) at the Georgia Institute of Technology. He is co-founder of the UPC-CCABA
(http://www.ccaba.upc.edu/). His publications include several book chapters and more than 100 papers in relevant
research journals (> 20), and refereed international conferences. His current research interests are in nanonetworking
communications, traffic monitoring and analysis, and highspeed and optical nnetworking, with emphasis on traffic
engineering, traffic characterization, MAC protocols, and
QoS provisioning. He has participated in many European
projects dealing with computer networking topics.
C H I R I S T I A N S I M O N N E A U (Christian.Simonneau@alcatel__________
lucent.fr)
_____ received a Ph.D. degree from the University of
Paris VI, France, in 1999 for work on nonlinear optics in IIIV semiconductors and optical fiber. He joined Alcatellucent France in 2000, where he has been involved in
research on fiber amplifiers, transparent optical mesh networks, and, more recently, optical packet switching technology. He has authored and co-authored more than 60
conference and journal papers and 18 patents.
DOMINIQUE BAYART (dominique.bayart@alcatel-lucent.fr)
__________ has
authored 15 post-deadline papers, invited talks at OFC,
ECOC, OAA, and LEOS, more than 100 technical papers on
EDFA and dynamic networks, and the books EDFA, Device
and System Developments (Wiley) with E. Desurvire and
Undersea Fiber Communication Systems (Academic Press),
and has filed 25 patents since 1991. He successively served
on the TPCs of OFC, OAA, and CLEO Europe, and in 2001
and 2004 received the Alcatel Distinguished Technical Staff
Award. After 10 years of management of research teams at
Bell Labs, he moved in 2008 to the Optics Competence
Center of Alcatel-Lucent.
____________________
D IMITRI S TAESSENS (dimitri.staessens@intec.UGent.be)
received his. M. Sc. degree in computer science in 2004
from Ghent University. In 2005 he joined the optical networking research group of the Department of Information
Technology, under a grant from the Interdisciplinary Institute for Broadband Technology (IBBT). His research focuses
on transparency, resilience, and control plane technologies
in future optical networks. He participates in several European FP6 and FP7 projects such as IST-NOBEL, NoE BONE,
and STREP DICONET, along with several national projects
on optical networking.
DIDIER COLLE (didier.colle@intec.UGent.be)
_______________ received an M.Sc.
degree in electrotechnical engineering (option: communications) from Ghent University in 1997. Since then he has
been working at the same university as a researcher in the
Department of Information Technology (INTEC). He is part
of the research group INTEC Broadband Communication
Networks (IBCN) headed by Prof. Piet Demeester. His
research led to a Ph.D. degree in February 2002. He was
granted a postdoctoral scholarship from the Institute for
the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen) in the period 2003–2004.
Currently he is co-responsible for research on advanced
network architectures and concepts, techno-economic
studies, green ICT, and advanced graph algorithms. His
research deals with design and planning of communication
networks. This work is focusing on optical transport networks to support the next-generation Internet. Until now,
he has been actively involved in several IST projects (LION,
OPTIMIST, DAVID, STOLAS, NOBEL, LASAGNE, DICONET,
and ECODE), in the COST-action 266 and 291, and in the
ITEA/IWT TBONES and CELTIC/IWT TIGER projects. His work
has been published in more than 200 scientific publications in international conferences and journals.
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SIP-Empowered Optical Networks for
Future IT Services and Applications
Franco Callegati, Aldo Campi, and Giorgio Corazza, University of Bologna
Dimitra Simeonidou, Georgios Zervas, Yixuan Qin, and Reza Nejabati, University of Essex
ABSTRACT
This article presents a novel applicationaware network architecture for evolving and
emerging IT services and applications. It proposes to enrich an optical burst switching network
with a session control layer that can close the
gap between application requests and network
control. The session control layer is implemented using the Session Initiation Protocol, giving
birth to what is called a SIP-OBS architecture.
The article discusses the important added value
of this architecture, and shows that it may support a number of end-to-end resource discovery
and reservation strategies (for both network and
non-network resources). Finally, it presents a
testbed implementation where this approach was
experimentally validated.
INTRODUCTION
The current trend suggests that future IT services will rely on distributed resources and fast
communication of multimedia contents. As a
consequence networks capable of high capacity,
great flexibility, and intelligence will be more
and more a key component for the implementation of such services. Optical networks indeed
offer a solution in terms of capacity, due to the
huge bandwidth available on dense wavelengthdivision multiplexing (DWDM links), but still
miss providing flexible and fast access to it.
The key building block to answer the needs
of foreseeable future IT services is the network
control plane, which should be able to:
• Accept and understand the application
requests in a user oriented language
• Search if the resources required are available and negotiate the best possible answer
to the requests of the specific application
• Provide access to the network resource in
order to transport information of various
sizes as effectively and efficiently as possible
Accomplishing all these tasks at once is not
easy, most of all because they span several logical layers of the network stack. Today’s solutions
for the network control plane usually focus “horizontally” on a subset of them, while a “vertical”
solution is missing. In this article we describe the
prototype implementation of a control plane for
an optical burst switching (OBS) network tai-
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lored to the needs of future IT services [1, 2].
The control plane is realized, with minor additions, by suitably combining already existing
building blocks, well-known technologies and
protocols, in a novel and original fashion. By
introducing the concept of service session supported by the Session Initiation Protocol (SIP)
[3], the experiments described in the article show
that the OBS network can be made applicationaware rather easily exploiting existing technology, thus confirming it as a good candidate for
the implementation of future consumer grids.
It is worth mentioning that a number of OBS
testbeds have been reported in the past [4, 5],
and have also been considered to enable optical
networking for distributed and collaborative
applications such as grids [6]. However, until
now application layer services (e.g. resource discovery, reservation, etc.) have been deployed
with the same mechanisms already used on the
IP network, with OBS used as a transport network. In most cases the grid signaling is also segregated on a separate IP infrastructure, and
OBS is used only to carry the application data.
In this article we make a step forward, proposing an architecture that can easily evolve into a
fully integrated infrastructure where the boundary
between application signaling, network control,
and information transport can almost disappear.
The article is organized as follows. We provide
a brief overview of the networking technologies
integrated in the proposed architecture. Then we
discuss the idea of exploiting session control to
implement application-aware networking, which is
the core of this work. The testbed implementation is described, providing some results obtained
running a video distribution application over this
testbed. Finally, some conclusions are drawn.
THE EXISTING BUILDING BLOCKS
As mentioned in the introduction, the aim of
this work is to prove that everything is ready to
implement an application-aware optical network
as long as the basic building blocks are chosen
and coupled appropriately. We want to show
with the experiments presented in this article
that the implementation of a service oriented
control plane is possible without major efforts in
designing new components, but rather by smartly
coupling protocols and technologies that are well
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known and widely available. So first we briefly
review these building blocks.
OPTICAL BURST SWITCHING
OBS is considered the medium-term solution to
implement fast all-optical switching, thanks to its signaling and bandwidth reservation scheme that logically separates the control and data planes. In
principle OBS combines the best of coarse-grained
optical wavelength switching and fine-grained optical
packet switching while avoiding their deficiencies. Its
transport format can be tailored to users’ quality of
service (QoS) and bandwidth requirements, and
therefore provide efficient use of network resources.
In an OBS network the bursts’ optical paths
are set up by means of signaling protocols such
as Just in Time (JIT) and Just Enough Time
(JET), which have in common some sort of endto-end communication (one-way, two-way, or
similar) carried by means of burst control packets (BCPs) sent by the edge nodes before the
optical bursts. Performance, QoS management,
and other aspects of these protocols have been
widely investigated in recent years.
On top of the end-to-end signaling required
to set up the optical path, an OBS network may
run a more general control plane component to
manage connections, QoS differentiation, traffic
engineering, and so on. For instance, this can be
done by exploiting generalized multiprotocol
label switching (GMPLS), which has proven to
be an efficient telecom-oriented solution for fast
and automated provisioning of connections
across multitechnology networks (IP/MPLS, Ethernet, synchronous digital hierarchy/optical network [SDH/SONET], DWDM, OBS, etc.).
GMPLS enables advanced network functionalities for traffic engineering, traffic resilience,
automatic resource discovery, and management.
Both GMPLS and JIT are horizontal control
plane components, in the sense that they focus on
a specific set of functions. They cannot easily be
interfaced directly with the applications; most of
all, they do not have the native capability to
understand high-level user needs or requirements.
THE SESSION INITIATION PROTOCOL
SIP is an Internet Engineering Task Force (IETF)
application layer protocol used to establish and
manage sessions. The concept of a session is well
known in networking but also in more general real
life, and is related to a set of activities performed
by a user that can be logically correlated. In networks several exchanges of information (either in
parallel or serial) may be part of a single session.
The session may be manipulated by the user or
the network according to the needs, for instanc,e a
session may be suspended, retrieved and so forth.
SIP deals with session-oriented mechanisms,
regardless of the scope(s) of a session. It specifies
the message flows required to initiate, terminate,
and modify sessions. In other words, SIP does not
provide services but provides primitives that can
be used to implement services on top of sessions.
For example, SIP can locate a user and deliver an
opaque object to its current location. It is also neutral to the transport protocol and can run on top of
almost all existing protocols (TCP, TSL, UDP).
Thanks to these characteristics SIP scales well, is
extensible, and sits comfortably in different archi-
tectures and deployment scenarios. Because of
these features SIP has become the core protocol of
the IP multimedia subsystemIMS architecture that
promises to pave the path toward ubiquitous communication over heterogeneous networks [8].
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Probably the most
well known
examples of an
THE APPLICATION PROTOCOLS
application protocol
Applications do communicate in their specific
languages to implement a service instance. Protocols exist to express end-user needs, find the
resources a user wants, and reserve them for
use. Probably the most well-known examples of
an application protocol today come from the
World Wide Web, where HTTP is the application protocol and URL is the language to express
the application needs.
Basically all IT services are built around similar protocols. Voice and messaging services over
the Internet (VoIP etc.) are another example,
where the protocols may be proprietary when the
application is mono-vendor (e.g., Skype) or based
on open specifications (e.g., the H.323 protocol
suite or Session Description Protocol and SIP).
In this article we refer to the scenario of a user
wanting to take part in a grid. The user has to find
the computational resources needed and exchange
the description of requirements of jobs to be dealt
with by the computational resources. Specific protocols exist to this end, generally based on abstract
XML-like syntax that fits the semantics specific to
the application environment. Examples are the
Resource Description Framework and the Job
Submission Description Language (JSDL) [7].
today come from the
World Wide Web,
where the HTTP is
the application
protocol and the
URL is the language
to express the
application needs.
THE SESSION LAYER AND
APPLICATION-AWARE NETWORKING
IT services have more complex requirements
than existing services. For instance, multimedia
communication poses real-time delivery and synchronization issues, grid computing breaks the
conventional shortest path routing paradigm
with the anycast concept, and peer-to-peer networking changes the client-server view of traditional Web services.
While the rather “trivial” issue of bandwidth
availability can be solved by brute force, enhancing the technology of the links and making them
more powerful, it is very unlikely the same can
be done with signaling since the existing protocols are simply not designed to take into account
the aforementioned requirements.
A trend we can envisage is that new services
tend to be state-full rather than state-less (as are
more traditional services). The more complex
communication paradigms require a number of
state variables to manage the information flows.
This is a tendency that can be found in the more
recent service-oriented Internet protocols. For
instance, TSL is a state-full protocol that manages encrypted connections within communication sessions.
Along this line we believe that the state-full
approach must also be pursued for an application-aware control plane. To this end the session
concept and SIP come into play:
• The sessions are used to handle the communication requests and maintain their state
by mapping it into session attributes.
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• The SIP protocol is used to manage the sessions since it provides all the primitives for
user authentication, session setup, suspension,
and retrieval, as well as modification of the
service by adding or taking away resources or
communication facilities according to need.
This proposal follows the same conceptual
paradigms as the IMS architecture [7] but in a simplified way, oriented to the core and edge architecture typical of a high-speed optical transport
backbone to which legacy networks are connected.
We assume the network is equipped with SIP-OBS
nodes to manage application-aware networking.
The logical scheme is shown in Fig. 1. The OBS
nodes (edge nodes in this example) are enhanced
Application layer
AO-M
APP-M
Session layer
SIP-M
NET-M
OBS
switch
OBS
SIP-OBS
node
Figure 1. Schematic of the SIP-OBS architectures. The session layer is
placed between the application and the OBS network. The figure shows the
SIP-OBS nod, coupling the AO-M with the OBS switch.
(P)
Legacy IP
(a)
(L)
OBS
(P)
Legacy IP
(b)
(L)
OBS
(P)
Legacy IP
(c)
(L)
OBS
Figure 2. Schematics of the various network architectures: a) overlay; b) fully
integrated; c) partially integrated.
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with an application-oriented module (AO-M). The
AO-M is logically subdivided into three modules:
• SIP module (SIP-M): built around a SIP proxy
implementing standard SIP communication
facilities, with the task of mapping the communication needs of applications into sessions
• Application module (APP-M): parses and
partially understands the application protocols that may be encapsulated in the SIP
messages
• Network module (NET-M): is able to interact with network signaling (e.g., OBS JIT in
this example)
The SIP-M is enhanced with interfaces toward
the upper and lower module. Combining the communication capabilities of APP-M and SIP, the
AO-M may assist applications in publishing, searching for, and reserving resources, thus understanding the related communication needs and mapping
them into sessions. Thanks to the NET-M, the
AO-M may trigger the network into creating the
connections required to transport the data flow
according to the service profile of a given session.
The SIP driven session layer and OBS transport layer may coexist with different levels of
physical and logical integration (Fig. 2):
• Pure overlay (Fig. 2a): where the legacy networks and the OBS transport network are
functionally separated.
–Physical (P). The SIP signaling and the
data are carried on separate infrastructures.
The legacy IP network based on conventional electronic routing carries the SIP signaling, while the OBS transport plane is
used to transfer the data.
–Logical (L). The AO-Ms are placed into
the edge routers only, and the application
resources (e.g., computing and storage) and
network resources are managed separately
in an overlay manner. The users (i.e., the
application) use SIP to negotiate IT communication sessions. When a session is set
the SIP-M triggers the NET-M responsible
for requesting a data path between the edge
routers involved in the session to the optical
network control plane. Then the session
data cut through the OBS transport plane.
• Full integration (Fig. 2b). No legacy networks are in play anymore. SIP signaling
and data share the same networking infrastructure.
–Physical. All data flows are switched
through the OBS networks, either signaling
(both SIP and OBS signaling) or user data,
in a unified manner. The bandwidth available on the optical layer is completely
shared between all communication needs.
–Logical. The optical control plane is
enriched with SIP functionalities, to realize
a pure OBS network interworking with the
session layer. All network nodes are fully
functional SIP-OBS nodes.
• Partial integration (Fig. 2c). Between the
two just presented, this solution still segregates most of the intelligence of the SIP
layer at the boundaries of the OBS network
while exploiting physical integration.
–Physical. All data flows are switched
through the OBS network as in the integrated solution.
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–Logical. The AO-Ms in the edge nodes are
fully functional and logically identical to
those mentioned before. On the other hand,
the AO-M in the core node is equipped
with a subset of functionalities to satisfy the
best performance/complexity trade-off. For
instance, the AO-M could be limited to a
SIP-M functioning as a light proxy with forwarding capabilities and the NET-M with
network resource management functions.
All abovementioned architectures can use
SIP messages to support IT services, in particular resource publication, discovery and reservation. An example is shown in Figs. 3 and 4.
The three crucial functions are:
• Resource publication. An IT resource
announces its capability as well as availability to the SIP-OBS router by utilizing a SIP
PUBLISH message (Fig 3a). The message
body is passed by the SIP-M to the APP-M
where it is processed, storing the combination of resource capability and availability.
Depending on whether the information
must be propagated in the network, the
PUBLISH message may be forwarded to
adjacent SIP-OBS routers or not.
• Resource discovery. An IT application
requests resources by issuing a SIP SUBSCRIBE message (Fig 3b). The characteristics of the request are included in the SIP
message body and interpreted in the APPM. Again, the specific protocol used is not a
major matter since the APP-M can be
extended to understand any new application
protocol. For the time being we focus on the
current standards, in particular the Resource
Description Framework (RDF) and Job
Submission Description language (JSDL).
Again, depending on where the database of
available resources is maintained, the SUBSCRIBE can be processed at the closest
SIP-M (e.g., the first SIP-OBS edge node
seen by the client user) or may need to be
forwarded within the SIP-OBS architecture.
In any case the SIP-OBS routers with available requested resources send a NOTIFY
message back to the user (Fig 3c).
• Resource reservation. After resource discovery, the user knows the location of the
resource and can attempt a direct reservation (Fig. 4) by an INVITE message. In
case of successful reservation the user gets
an acknowledge back and may submit the
job over a JIT OBS network as shown.
EXPERIMENTAL VALIDATION OF THE
SIP-OBS CONCEPT
The previous concepts have been validated by
implementing a real-life SIP-OBS testbed. The
work stands as a successful international collaboration. The SIP-M was developed by the University of Bologna and the OBS testbed
implemented at the University of Essex. Thanks
to staff members’ mobility, the two parts were
integrated into a single fully functional testbed,
and the various concepts previously described
were tested. Basically two main experiments are
described in this work; the former experiment
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SIP-OBS
SIP-OBS
AO-M
PUBLISH
200 OK
SUBSCRIBE
200 OK
(a)
SUBSCRIBE
200 OK
NOTIFY
200 OK
(c)
NOTIFY
200 OK
Direct reservation
Figure 3. Examples of application oriented functions supported by the SIPOBS network: a) resource publication; b) discovery; c) notification.
aimed to validate the concept in terms of feasibility and consistency of signaling timing; the latter was to demonstrate a more realistic situation
where an application requests a resource and the
SIP-OBS network delivers it accordingly.
Because of its significant complexity, the OBS
testbed has a rather simple network topology
with two edge nodes and a single core node. In
practice this topology does not provide any significant challenge in terms of networking complexity; therefore, it was not meaningful to try a
comparison of the various logical architectural
alternatives mentioned earlier. Nonetheless, the
full functionalities of the concepts described
have been tested and their feasibility proved.
TESTBED DESCRIPTION
The OBS testbed operates at 2.5 Gb/s for both
the data and control planes. The OBS specific
control functionalities are implemented on a Xilinx high-speed and high-density VirtexII-Pro field
programmable gate array (FPGA) with an
embedded network processor. The OBS control
channel is transmitted on a dedicated wavelength
channel in the same fiber using the proprietary
Optical Burst Ethernet Switched (OBES) transport protocol. The data plane transports variablesize bursts with variable time intervals and
operates in bursty mode. The ingress edge router
utilizes one fast and widely tunable SG-distributed Bragg reflector (DBR) laser for data transmission, and implements all the functions required
to aggregate IP packets into bursts and allocate a
suitable wavelength and burst control header
(BCH) to them. The egress side integrates a
clock and data recovery (CDR) mechanism, a
word alignment unit (WAU), and a segregation
IP unit (SIPU). The core router was implemented with different switching technologies in the
two experiments, mainly for component availability reasons. The first experiment utilizes a 4 × 4
optical crossconnection (OXC) operating at
nanosecond switching speed, whereas the second
experiment utilizes a millisecond range 8 × 8
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MEMS switch. The FPGA implements the switch
control and the optical switch performs the burst
routing. The FPGA extracts and processes the
incoming BCH through a CDR and WAU, drives
the optical switch with appropriate control signals, and reinserts a new BCH. More technical
details on the testbed are beyond the scope of
this article but can be found in [9, 10].
The AO-M is implemented in the testbed by
introducing a session layer as described in the previous sections. The SIP-M is based on the pjsip
(http://www.pjsip.org) SIP stack. The stack has
been suitably extended, implementing the forwarding functions (not present in the original version)
and extension modules (APP-M and NET-M). The
APP-M in the experiment is a JSDL parser that is
able to understand job subscription requests by the
applications. The NET-M is an interface with the
FPGA card controlling the node. In this way the
SIP protocol is able to interact with the network
and trigger the JIT protocol to set up optical paths
to carry optical bursts. For this reason we refer to
the experimental solution as a JIT-SIP protocol
stack that utilizes SIP functionalities to negotiate
and manage the application sessions and JIT signaling to reserve optical network resource and
manage the physical layer connections.
SIP-OBS
SIP-OBS
OBS
AO-M
AO-M
INVITE
100TRY
INVITE
100TRY
Ts1
INVITE
100TRY
200 OK
(a)
200 OK
200 OK
Ts2
ACK
ACK
ACK
Job submission
BCH
BCH
Job submission over burst
Job submission
(b)
BCH
BCH
Job result over burst
Job result
BYE
200 OK
(c)
BYE
200 OK
Figure 4. Examples of application-oriented functions supported by the SIPOBS network: a) INVITE reservation; b)communication over JIT OBS;
c) session teardown.
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FIRST EXPERIMENT
The first experiment aimed at demonstrating the
feasibility of the concept. The architecture implemented is the simplest one: physical and logical
overlay. The SIP signaling is carried over a conventional IP network (Fast Ethernet) while the data
bursts are carried over optical bursts. The emulated data traffic is generated within NET-M e and
are not related to any specific application. The
resource configuration is static and built a-priori.
In the experiment, a user is connected to one
of the SIP-OBS edge router (SIP-OBS-1) and
wants to reserve a resource. The resource is
attached to the second SIP-OBS edge node
(SIP-OBS-2).
The user sends its request to the AO-M integrated in the SIP-OBS-1 node. The request (SIP
INVITE message) carries the job specification
and resource requirements (i.e., computational
and network) in the payload, in the form of a
JSDL document.
The message-timing flow between the OBS
edge nodes is presented in Fig. 4. After the
INVITE message is processed, the user is informed
about the results of the resource discovery, with
either a positive or negative reply, depending on
whether or not resources are available. In the
experiment the positive reply is the 200 OK message received by the SIP-OBS edge node at TS1 =
14.45 ms (experimentally measured) after sending
the INVITE message. In this case the AO-M forwards the OK message to the client. The application could start sending data at this time.
In the meantime a computational resource
reservation signaling (ACK) message is sent to
the SIP-OBS-2 node (after TS2 = 17.95 ms). This
is to acknowledge the session establishment. The
time elapsed between the arrival of the OK message and the departure of the ACK is due to the
signaling between SIP-OBS-1 and the client (not
reported in the figure), and triggering the application to transfer the data referring to the communication session under negotiation.
In the data transport part of the OBS testbed,
variable length optical bursts (from 60 to 400 Rs)
with their associated BCHs in three different
wavelengths were demonstrated (Q5 = 1538.94
nm, Q6 = 1542.17 nm, and Q7 = 1552.54 nm for
data bursts) [9]. The transmission showed an
extinction ratio of 13.6 dB at the output of SIPOBS-1, 12.8 dB after output port 1 of the OXS
and at the received point of SIP-OBS-2.
SECOND EXPERIMENT
Job result
BYE
200 OK
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The second experiment implemented a fully functional test application based on video on demand
(VoD). The video server is connected to SIP-OBS2 and makes available a number of movies. The
network architecture is still overlay in logical terms
but is fully integrated in physical terms. The SIP
messages travel over the OBS transport plane
together with the user data. In this testbed all signaling messages are carried over a separate set of
wavelengths (OBS control plane) with respect to
the user data as in conventional OBS architectures.
The video server publishes a list of the available movies (resources) at the AO-M integrated at
the SIP-OBS-2 node with a PUBLISH SIP message. The client application is connected at SIP-
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OBS-2 and requests the list of available movies
(using the SUBSCRIBE message). The SIP-M
manages the session establishment and triggers
the video over OBS transmission. An INVITE SIP
message is used to request, discover, and activate
the VoD application service (video server) to
stream video over OBS. The JIT-SIP control protocol performance has been evaluated by measuring the resource reservation time (from the time
the INVITE is sent from the user side to the time
the ACK is received by the resource site), which is
60 ms. This value is mostly dependent on the end
host performance used for the AO-M and not the
actual OBS testbed. Independent evaluation of
the SIP proxies with a single dual 2.4 Ghz Xeon
PC with 2 Gbytes of RAM virtualizing neighbor
proxies has proven that a speed of 0.2 ms is
required to process the INVITE message.
The JIT-SIP messages encapsulated in BCHs
are sent over the OBS control plane, and the
generated optical bursts over the data plane.
Waveforms of the data bursts in the data plane
are shown in Fig. 5 in three different timescales.
The VoD application generates traffic (video
streaming) of around 1 Mb/s with fixed-size 1370byte UDP packets. FTP background traffic of
around 20 Mb/s is also generated and added to
the video traffic in order to emulate current
Internet traffic behavior (between TCP and UDP
data). The aggregation developed is hybrid and
combines both size and time threshold. The maximum size threshold is set to 5000 bytes and time
limit to 2 ms. These are set based on the total
incoming traffic load (~21 Mb/s) and the low
latency requirement. The video server generates
MPEG-2 fixed size UDP packets (1370 bytes).
Figure 6 shows that more than 95 percent of
the UDP packets have a delay of less than 30 ms
with a maximum delay of just over 80 ms, which
is well within the acceptable level. This figure
also shows that the jitter also remains below 1.8
ms for 100 percent of the traffic, also a well
accepted value. The packet loss of the OBS network is zero for the whole amount of data.
4.000 μs/div
500.02197 μs
Figure 5. Protocols deployed and demonstration results: bursts over data.
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
OBS
+
FTP (in background)
0
10
20
30
e)
SCALABILITY ISSUES
One last issue that could not be addressed with
the available testbed for dimension reasons is
scalability. The experiments presented above
showed the feasibility of the concepts, but in a
rather simple and small network topology due to
the constraints on availability of optical hardware. We then made some evaluations to test the
scalability of the proposed SIP-OBS approach.
Regarding publishing (PUBLISH), discovering
(SUBSCRIBE), and reserving (INVITE)
resources, the processing time of these single messages and the total amount of time required to
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100.0 μs/div
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0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0.2
40
Delay(ms)
50
60
70
80
OBS
+
FTP (in background)
0.4
0.6
0.8
1
Jitter(ms)
1.2
1.4
1.6
1.8
Figure 6. Protocols deployed and demonstration results: delay and jitter measurement of VoD application over OBS.
forward messages to the neighbor proxies is one of
the main issues. The results shown in Table 1 project the time between the request of a user agent
and the proxy’s processing time to forward the
message to all neighbor proxies, thus the total
amount of time to broadcast a message into the
Messages to proxy/
number of proxies
1
2
5
10
20
40
INVITE -> 404 Not Found
0.206
0.311
0.316
0.759
1.371
2.472
PUBLISH -> 200 OK
0.169
0.243
0.317
0.737
1.405
2.037
SUBSCRIBE -> NOTIFY
0.291
0.368
0.602
0.824
1.326
2.432
■ Table 1. Timing results (ms) of SIP messages on a set of Proxies.
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network. The tests were performed with a single
dual 2.4 Ghz Xeon PC with 2 Gbyte of RAM virtualizing neighbor proxies. In addition to this,
Table 1 shows the processing time between the
request of a user agent and the proxy response for
all possible SIP messages on a standalone proxy.
These numerical results prove that the proposed solution can scale quite well. The results
reported are compatible with real-life applications
for several tens of nodes, even in simulations performed with standard off-the-shelf computers.
CONCLUSIONS
This article describes a possible extension to the
conventional control plane of an OBS network with
functionalities that makes it able to communicate
with end-user applications and understand their
needs. This has been achieved by introducing a session control layer implemented by SIP on top of
the conventional network control plane. The proposed architecture was implemented as part of a
fully functional OBS testbed, and its feasibility was
proven in a series of experiments culminating in
running a fully functional multimedia application.
ACKNOWLEDGMENT
The work described in this article was carried out
with the support of the e-Photon/One+ and
BONE (“Building the Future Optical Network in
Europe”) projects, Networks of Excellence funded
by the European Commission respectively through
the 6th and 7th ICT-Framework Program.
REFERENCES
[1] D. Simeonidou et al., “Dynamic Optical-Network Architectures and Technologies for Existing and Emerging
Grid Services,“ IEEE J. Lightwave Tech., vol. 23, no. 10,
2005, pp. 3347–57.
[2] M. De Leenheer et al., “A View on Enabling Consumer
Oriented Grids through Optical Burst Switching,” IEEE
Commun. Mag., vol. 44, no. 3, Mar. 2006, pp. 124–31.
[3] J. Rosenberg et al., “SIP: Session Initiation Protocol,”
IETF RFC 3261, June 2002.
[4] K. Kitayama et al., “Optical Burst Switching Network
Testbed in Japan,” Proc. OFC 2005, Anaheim, CA, Mar.
2005.
[5] Y. Sun et al., “A Burst Switched Photonic Network
Testbed: Its Architecture, Protocols and Experiments,”
IEICE Trans. Commun., vol. E88-B, no. 10, Oct. 2005,
pp. 3864–73.
[6] S. R. Thorpe, D. S. Stevenson, and G. K. Edwards,
“Using Just-in-Time to Enable Optical Networking for
Grids,” Wksp. Networks for Grid Apps., co-sponsored
by BroadNets, 2004.
[7] A. Anjomshoaa et al., “Job Submission Description Language (JSDL) Specification v. 1.0,” Open Grid Forum
doc. GFD.56, Nov. 2005.
[8] M. Poikselka et al., The IMS: IP Multimedia Concepts
and Services, 2nd ed., Wiley, 2006.
[9] G. Zervas et al., “SIP-enabled Optical Burst Switching
Architectures and Protocols for Application-Aware Optical Networks,” Comp. Networks, 2008, doi:10.1016/j.
comnet.2008.02.016
[10] G. Zervas et al., “A Fully Functional Application-Aware
Optical Burst Switched Network Test-Bed,” OFC ’07,
paper OWC2, Anaheim, CA.
BIOGRAPHIES
F RANCO C ALLEGATI (franco.callegati@unibo.it)
_______________v is currently
serving as an associate professor at the University of
Bologna, Italy. He received his Master’s and Ph.D. in electrical engineering in 1989 and 1992 from the same university. He was a research scientist at the Teletraffic Research
Centre of the University of Adelaide, Australia; Fondazione
U. Bordoni, Italy; and the University of Texas at Dallas. His
research interests are in the field of teletraffic modeling
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and performance evaluation of telecommunication networks. He has been working in the field of all optical networking since 1994 with particular reference to network
architectures and performance evaluation for optical burst
and packet switching. He participated in several research
project on optical networking at the national and international level, such as ACTS KEOPS, IST DAVID, and IST Ephoton/ONe, often coordinating work packages and research
activities.
ALDO CAMPI (aldo.campi@unibo.it)
___________ received a degree in electronic engineering from the University of Bologna in 2004.
Currently he is a Ph.D. student in the field of telecommunication at the same university, where he has participated in
research project on optical networking at the international
level, such as IST E-Photon/One+ and IST BONE, working
actively on many work packages and research activities. In
2007 he spent 10 months at the University of Essex, United
Kingdom, as visiting researcher working on applicationaware networking His research interests include optical networks, scheduling algorithms, SIP, grid networking, and
service-oriented and NGN architectures.
GIORGIO CORAZZA (giorgio.corazza@unibo.it)
_____________ is a full professor of telecommunication networks at the University of
Bologna. He received a Dr.Eng. degree in electronic engineering from the University of Bologna in 1969. His
research activity started in the field of digital transmission
with special emphasis on phase and frequency modulation
systems. He has also been concerned with electronic aids
to air navigation. In the last years he has been involved in
research on broadband switching and optical networking.
He has participated in several EU funded research projects
in optical networking and was coordinator of two national
research projects, IPPO and INTREPIDO.
DIMITRA SIMEONIDOU (dsimeo@essex.ac.uk)
__________ is head of the Photonic Networks Group and the newly established High Performance Networked Media Laboratory at the University of
Essex. She joined the university in 1998 (previously she was
with Alcatel Submarine Networks). She is an active member
of the optical networking and grid research communities,
and participates in several national and European projects
and initiatives. Her main areas of research are photonic
switching, ultra high-speed network technologies and architectures, control and service plane technologies for photonic
networks, and architectural considerations for photonic grid
networks. She is the author or co-author of over 250 papers,
11 patents, and several standardization documents.
G EORGIOS Z ERVAS (gzerva@essex.ac.uk)
___________ was awarded an
M.Eng. degree in electronic and telecommunication systems engineering with distinction and a Ph.D. degree in
optical networks for future applications from the University
of Essex in 2003 and 2009, respectively. He is a senior
research officer with the Photonic Networks Laboratory at
the University of Essex involved in EC funded projects
MUFINS, e-Photon/One+, Phosphorus, and BONE. He is an
author or co-author of over 40 papers in international journals and conferences. His research interests include highspeed optoelectronic router design, optical burst switched
networks, GMPLS networks, and grid networks. He is also
involved in standardization activities in the Open Grid
Forum (OGF) through the Grid High Performance Networking Research Group (GHPN-RG) and Network Service Interface Working Group (NSI-WG).
R EZA N EJABATI (rnejab@essex.ac.uk)
___________ has over 10 years of
academic and industrial experience in the field of highspeed network switches and programmable router design.
He received his M.Sc. degree in 2002and Ph.D. degree in
2007 in the field of optical telecommunication and networking from the University of Essex. He is currently a
research academic fellow in the Photonic Network Research
Group at the same university. His main current areas of
interest are design and control issues for high-speed electronic and optoelectronic interfaces in photonic packetbased networks as well as architectural considerations for
photonic grid networks.
YIXUAN QIN (yqin@essex.ac.uk)
_________ received his M.Sc. degree in
computer and information networks from the University of
Essex in 2003, where he is currently working toward his
Ph.D. degree. In addition, he is a research officer in the
Photonic Networks Laboratory. His research interests
include high-speed digital system design, flexible networks,
passive optical networks, and optical burst switching.
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Impairment-Aware Routing and
Wavelength Assignment in Translucent
Networks: State of the Art
Maurice Gagnaire and Sawsan Al Zahr, Télécom ParisTech (ENST)
ABSTRACT
In the last 15 years, numerous investigations
by both academia and industry have been carried
out in the field of all-optical WDM networks’
design. In all-optical — or transparent — WDM
networks, data is transmitted from its source to
its destination in optical form, switching/routing
operations being performed in the optical
domain without undergoing any optical-to-electrical conversion. Optical transparency may considerably reduce network infrastructures’ cost
and extend the range of services offered by the
carriers. Designing an all-optical network consists of assigning to each traffic demand an endto-end optical circuit, also called “lightpath.” In
such networks, the problem of routing and wavelength assignment (RWA) aims to find an adequate route and an adequate wavelength for
each traffic demand subject to the wavelength
continuity constraint and limited network
resources. The feasibility of the obtained lightpaths in terms of admissible quality of transmission (QoT) presents another difficulty. Indeed,
according to the state of technology, various
physical impairments degrade the quality of the
optical signal along its propagation. Optical
fibers and optical amplifiers as well as optical
switching/routing nodes impact on end-to-end
QoT. In this context only translucent networks
are achievable, for instance, at a pan-European
or pan-American scale. A translucent network
uses electrical regenerators at intermediate
nodes only when it is necessary to improve the
signal budget. The cost of a network is roughly
proportional to average number of input/output
ports of a node. Knowing that today an optical
port is five times less expensive than an electrical
one, sparse regeneration allows translucent
WDM networks to meet the QoT requirements
and achieve performance measures close to
those obtained by fully opaque networks at much
lower cost. In this article we propose a state of
the art in the field of impairment-aware RWA
(IA-RWA), starting from the case of predictable
traffic demands to the open problem of stochastic traffic demands. An economic analysis of the
IA-RWA problem is proposed to justify the concept of translucent networks. The case of multi-
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domain lightpath establishment is also considered. Several examples of still open problems
are mentioned in the article. Most of the concepts and results presented in this article refer to
the FP7 DICONET European project in which
the authors are involved.
INTRODUCTION
The emergence of wavelength-division multiplexing (WDM) multiplexers in the 1990s enabled a
strong boost in the capacity of optical fibers,
while electrical regenerators that were used
roughly every 70 km (43 mi) have been replaced
by optical amplifiers. In parallel, numerous
advances have been achieved in the field of optical switching and quality of transmission (QoT)
monitoring. The feasibility of optical cross-connects (OXCs), optical circuit switches (OCSs),
and optical packet switches (OPSs) has been
demonstrated in the last decade. Hardware technologies for OXCs and OCSs are mature. Studies like those carried out within the Dynamic
Impairment Constraint Networking for Transparent Mesh Optical Networks (DICONET)
project are dedicated to the specification of a
control/management plane for dynamic lightpath
establishment (see the article of our colleagues
included in this issue). In this context two types
of traffic demands, either static or dynamic must
be considered. In the first case traffic demands
are semi-permanent, with routing and wavelenth
assignment (RWA) mainly used for network
planning. In the latter case the lifetime of a traffic demand is finite while remaining larger than
network round-trip time. The specification of a
signaling channel is necessary for automatic
dynamic lightpath establishment. Either predictable or stochastic traffic demands are considered in the case of dynamic traffic. It has been
shown that solving the RWA problem under
dynamic and predictable traffic demands,
referred in the literature to as scheduled traffic
demands (STD), may be carried out offline. In
that case RWA is one of the main functionalities
of the management plane. When assuming
dynamic and predictable traffic demands, RWA
consists of a global optimization tool that compares the costs of all feasible RWA solutions for
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The analog optical
signal is subject to
Inline amplifier
Laser
Modulator
Switch fabric
Demux
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two main types of
attenuation:
intrinsic and extrinsic.
DCM
DCM
Intrinsic attenuation
Pre-line
amplifier
is due to the
absorption of the
optical power in
Mux
Post-line
amplifier
Transponder array
Fiber span
Fiber link
silica. Extrinsic
Client (SONET/ATM/SAN)
attenuation is due to
irregularities in the
section of the
Node B
Node A
Node C
Figure 1. Configuration of a WDM transmission system.
cylindrical geometry
of the fiber.
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the whole set of traffic demands. A solution’s
cost is expressed in terms of required optical and
electrical ports. Dynamic and stochastic traffic
demands are characterized by an unknown
arrival time and a random lifetime. This unpredictability of the traffic imposes on-the-fly RWA
applied to individual demands. This task must be
done in real time and is the main functionality
of the control plane. Although all-optical wavelength converters are technically feasible, their
cost remains prohibitive for carriers. This is the
reason two main constraints must be considered
when solving the RWA problem: wavelength
continuity and the limited number of optical
channels that may be multiplexed onto the same
fiber.
Only since 2000 has real attention been paid
to the impact of transmission impairments on
the feasibility of solutions provided by RWA
[1]. According to the state of the technology,
various factors degrade the quality of an analog
optical signal along its route due to propagation itself, multiplexing, amplification, and
switching. Many investigations have tried to
include QoT constraints in RWA strategies;
these constraints may be classified into linear
and nonlinear impairments. Linear impairments
are such that their impact on QoT is independent of the power of each of the optical channels transported on the same fiber. At the
opposite, nonlinear impairments are strongly
dependent on the accumulated power and on
the individual power of the optical channels
transported in parallel on the same fiber. The
higher the bit rate of the data transported by a
lightpath or the larger the length of the route
adopted for a lightpath, the higher the required
optical power at the transmitter. In other terms,
under linear impairments QoT can be evaluated individually for the different optical channels sharing the same fiber. This is not the case
under nonlinear impairments, wherein the QoT
of each optical channel transported on a fiber
depends on the number, value, and power of
the other channels transported simultaneously
on the same fiber. Impairment-aware RWA
(IA-RWA) consists of solving the RWA problem while taking into account QoT constraints.
Today, the great majority of the investigations
on IA-RWA are dedicated to static traffic. The
case of IA-RWA with dynamic traffic remains
widely open to further study; it is a key objective of the DICONET project.
The aim of this article is to provide an
overview of the state of the art of IA-RWA. We
recall the main physical layer impairments to be
considered for QoT evaluation. As mentioned in
the abstract, full optical transparency is in practice not achievable with the state of the technology. This is why the concept of a translucent
network has been introduced. We discuss the
necessary economical trade-off for carriers
between opacity and transparency. Numerous
technologies enable the impact of physical layer
impairments on QoT to be reduced. Meanwhile,
beyond a certain distance, electrical regeneration
becomes mandatory if QoT at intermediate
nodes degrades beyond an admissible limit. This
limit is referred to as the Q-factor threshold. We
also dedicate a section to static IA-RWA. The
main task of static IA-RWA is to determine the
most judicious locations for electrical regeneration in the network. We then deal with the more
prospective problem of dynamic IA-RWA. We
propose an introductory analysis of IA-RWA in
the context of multidomain lightpath establishment. We then conclude this article.
PHYSICAL LAYER IMPAIRMENTS
Figure 1 recalls the typical configuration of a
point-to-point WDM transmission system. In
carriers’ networks optical fibers are set in pairs
between adjacent nodes, a fiber for each direction of transmission. At the source node, parallel
optical channels generated by fixed transceivers
are multiplexed onto a standard single-mode
fiber (SMF). An optical pre-amplifier (postamplifier) is used at the input (output) of each
switching node. The WDM multiplex is regularly
re-amplified at amplification sites spaced on
average 80 km apart. A span corresponds to the
section of fiber separating two adjacent amplification sites. An optical link is the set of spans
used between two adjacent switching nodes. A
lightpath generally overlaps several links; intermediate nodes (electrical cross-connects [EXCs]
or OCSs) are in charge of lightpath routing.
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QoT is evaluated at the destination node of a
lightpath by computing the Q-factor, which is
directly linked to the bit error rate (BER) and
optical signal-to-noise ratio (OSNR). As an indication, a Q-factor of 12.5 dB corresponding to a
BER of 10–5 is frequently considered the Q-factor admissibility threshold when forward error
correction (FEC) is applied.
LINEAR IMPAIRMENTS
Attenuation (F): The analog optical signal is
subject to two main types of attenuation: intrinsic and extrinsic. Intrinsic attenuation is due to
the absorption of the optical power in silica.
Raleigh scattering due to the interaction between
photons and silica molecules causes scattering in
multiple directions. Attenuation due to Rayleigh
scattering is more sensitive for short wavelengths
(in nanometers) than longer ones. Extrinsic
attenuation is due to irregularities in the section
of the cylindrical geometry of the fiber. Both
attenuations are expressed in dB per kilometer.
Global attenuation F of SMF fibers (other types
of fiber can be used for very long-haul transmission systems) is about 0.2 dB/km
Amplified spontaneous emission: Erbium
doped fiber amplifiers (EDFAs) are subject to
spontaneous emission that corresponds to photons generated by the non-controlled return of
excited electrons in Erbium ions to their stable
state. Such photons do not coincide in time and
phase with those belonging to the incoming optical signal. The impact of amplified spontaneous
emission (ASE) is expressed in terms of OSNR.
Even if one assumes perfect compensation for
the attenuation of a span by an EDFA, the
inverse of OSNR at the output of an EDFA is
equal to the summation of the inverse of OSNR
at its input and the ratio of the ASE power to
the input power. ASE is related to the noise figure (NF) of the amplifier. Figure 2 illustrates the
typical evolution of OSNR over multiple spans.
Chromatic dispersion: CD is due to the fact
the various spectral components of a modulated
analog optical signal do not propagate with the
same speed in the fiber. This propagation speed
disparity induces intersymbol interference (ISI)
at destination. CD depends on wavelength and
increases with distance. It is expressed in picoseconds per nanometer or kilometer. CD is considered as one of the most penalizing linear
impairments on QoT. CD of SMF fibers is about
+17 ps/nm.km.
Polarization mode dispersion: PMD is due to
unpredictable birefringence in the fiber, this
birefringence being due itself to the non-circularity of the core of the fiber. The fact the two
orthogonal polarization directivities of the electro-magnetic field do not propagate at the same
speed induces a phenomenon similar to ISI at
the destination. Being expressed in ps per square
root of km, the square of PMD value is additive
with distance. As an indication, the International
Telecommunication Union — Telecommunication Standardization Sector (ITU-T) recommends, for a 2 Gb/s (10 Gb/s) channel, a limited
cumulated PMD of 40 ps (10 ps) after 400 km of
propagation. Unlike CD, PMD is wavelengthpindependent. PMD of SMF fibers is about 0.1 ps
per square root of km.
OSNRinput L = 80 km
L=80 km
L = 80 km
Tx
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L = 80 km OSNRoutput
Rx
Transmit power P
OSNRinput
OSNR1
OSNR2
OSNR3
OSNRoutput
P
Distance
P - αL
Distance
Figure 2. Impact of EDFA's ASE on OSNR.
Insertion loss: IL corresponds to the difference between the power of the optical signal at
the input and output of an opto-electronic
device. IL expressed in dB is considered in the
calculation of the power budget (OSNR) of a
lightpath. The penalty induced by the transit
through an OXC or OCS strongly depends on
the hardware architecture of the switching fabric; it is evaluated in terms of IL.
NONLINEAR IMPAIRMENTS
Nonlinear impairments may be classified into
two categories. The first category refers to the
impact of optical power on the fiber’s refractive
index. Such an impact is known as a Kerr effect.
Three Kerr effects are distinguished: self-phase
modulation (SPM), cross-phase modulation
(XPM), and four-wave mixing (FWM). SPM
induces a phase shift of the optical pulses. The
other category refers to scattering effects
between silica and optical signal. Stimulated
Raman scattering (SRS) and stimulated Brillouin scattering (SBS) are the two scattering
effects. In practice, the impact of SRS and of
SBS on OSNR is negligible compared to SPM,
XPM and FWM. FWM is the most penalizing
impairment among Kerr effects. The cumulated
impact of the various nonlinear impairments is
in general expressed as a nonlinear phase shift
(+ NL) expressed in rad/s. + NL depends on the
value of the wavelength and is cumulative with
distance.
IMPAIRMENT COMPENSATION TECHNIQUES
In order to compensate for cumulated CD,
each amplification site uses a dispersion compensation fiber (DCF) section with a strong
negative CD of about –90 ps/nm.km. This
DCF section is inserted between the two
amplification stages of an amplification site.
In current carrier networks, EDFAs operate
in the C-band (1530–1560 nm) where attenuation is minimal. An EDFA enables up to 60
optical channels to be amplified simultaneously with a 40 dB global gain and a noise figure
around 5 dB.
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C1 = cost induced
by the number of
electrical/optical ports
C2 = cost induced by
physical impairment
Ideal translucent network compensation
Transparency
is not economically
viable
Transparency
is cost effective
C1+C2
C2
C1
Opaque
Average range
L of a lightpath
Transparent
Lmax
Lcrit
Figure 3. Opaque, translucent, and transparent networks.
FLAT VS. NON-FLAT BEHAVIOR ASSUMPTION
In most studies optical fibers’ CD and EDFA’s
penalty on OSNR are assumed to be flat, that is,
independent of the wavelength used by the considered lightpath. In practice, this assumption is
not valid. Hence, CD is wavelength-dependent.
Similarly, the gain of an EDFA is not flat in the
C-band. Wavelength allocation strategies may
then have a strong impact on system performance [2]. Dynamic gain equalization (DGE)
enables compensation for non-flat gain and
wavelength-dependent NF of EDFAs.
TRANSLUCENT OPTICAL NETWORKS
The amount and complexity of the equipment
required in the network to compensate for QoT
degradation increases with distance and bit rate.
Thus, ultra long haul (ULH) equipment covering
ranges from 880 mi (1500 km) to 1800 mi (3000
km) are much more costly than long haul (LH)
transmission equipment operating from 90 mi (90
km) to 430 mi (700 km). The STM-16 and STM64 standardized data rates at 2.5 Gb/s and 10
Gb/s, respectively, are currently widely deployed
in LH systems. The first STM-256 equipment
operating at 40 Gb/s more specifically dedicated
to ULH systems are complex to design, mainly
because of their sensitivity to nonlinear impairments. CD compensation and DGE are more
complex and costly to deploy in ULH systems
than in LH systems. In general, FEC techniques
are strongly recommended in ULH or with STM256 to prevent excessive BER at the destination.
As an indication, current FEC enables BER to
be reduced from 10–5 to 10–12.
Figure 3 illustrates the principle of the necessary trade-off for a carrier between full opacity
and full transparency. The horizontal axis refers
to the average range L of the lightpaths on the
considered network. The left side vertical axis
corresponds to the cost C1 of the required optical and electrical ports provided by a solution of
the RWA problem for a given set of traffic
demands and a given physical infrastructure. The
right side vertical axis corresponds to the cost C2
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of the equipment to be used in the network to
compensate for QoT degradation of the obtained
lightpaths in order to get an admissible BER at
the destination. In the case of a fully opaque
network, electrical regeneration is systematically
applied at intermediate nodes. Opaque networks
correspond to current networks made of EXCs
(e.g., a synchronous digital hierarchy [SDH]
cross-connect) or electrical switches (asynchronous transfer mode [ATM], Ethernet, frame
relay switches). Let us recall that in existing core
networks, IP routers are interfaced with layer 2
switches in order to benefit from multiprotocol
label switching (MPLS) constraint-based routing
and traffic engineering. As mentioned in our
introduction, the cost of an RWA solution is
expressed as the cumulated cost of electrical and
optical ports required in the network, the cost of
an electrical port being around five times higher
than the cost of an optical port. If the average
range of the lightpaths is extended in order to
overlap at least two hops, a fraction of the electrical ports initially required by the opaque
architecture is replaced by optical ports, leading
to a reduction of C 1. On one hand, we can say
that the higher the lightpath range, the lower C1.
At the limit, full transparency reduces the number of electrical ports to a minimum corresponding to the transceivers used at the source and
destination nodes. On the other hand, the larger
the range of a lightpath, the higher the cost of
the compensation techniques necessary to guarantee an admissible Q-factor at the destination.
We see from Fig. 3 that for any network configuration there is a maximum distance L max for a
lightpath to operate without QoT compensation
techniques. We can assume that QoT is at least
acceptable on any single hop of the physical
topology. Beyond Lmax, C2 increases progressively. In practice, in wide transport networks such
as the North American backbone, full transparency is not achievable. As described later,
various configurations are considered in the literature for translucent networks. In this section
we consider the case for which all the nodes are
transparent (e.g., OXCs or OCSs) and equipped
with a pool of electrical regenerators. Figure 4
illustrates the architecture of a translucent node.
The main problem of IA-RWA is then to determine the ideal sites where electrical regeneration
is necessary in order to minimize the global cost
C1 + C2. It has to be noted that electrical regeneration indirectly relaxes the wavelength continuity constraint, which then impacts on network
congestion.
The right side of Fig. 3 corresponds to transparent networks. In existing LH networks, transparency may not be achievable for all traffic
requests, as some demands are rejected by the
management/control plane. We can conclude
from Fig. 3 that theoretically, assuming translucent nodes, there is a critical length L crit for
which (C 1 + C 2 ) is minimal. As long as L
remains under L crit, transparency is cost effective. Beyond this value, transparency is economically not viable. The next sections show that
determining the ideal location of electrical
regenerator placement to reach this minimum is
a complex objective because of the amount and
nature of the parameters to take into account.
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STATIC IA-RWA
We have distinguished in our introduction
three types of traffic: semi-permanent, dynamic
and predictable, and dynamic and random.
Adding to the complexity of the RWA problem
the complexity of QoT management has driven
most studies to investigate in a first step static
IA-RWA [3–5]. In general, only the impact of
linear impairments (F, CD, PMD, IL) is considered. Few recent investigations take into
account FWM in proposing suited wavelength
assignment strategies [6]. For a given set of
traffic demands and infrastructure, two main
approaches are considered. The first consists of
minimizing the global number of electrical
regenerators; the second aims to minimize the
number of regeneration sites. From the operator’s perspective, we can say that the first
approach is capital expenditure (CAPEX) driven, the second operational expenditure (OPEX)
driven. The CAPEX-driven approach is intuitive. In this case with electrical regenerators
placed sparsely in the network, we may expect
that a certain number of nodes do not need a
bank of electrical regenerators. Figure 5 depicts
an example of results obtained with a CAPEXdriven IA-RWA [5] applied to the 18-node
NSFNET backbone described in Fig. 6. In this
network the average distance between adjacent
nodes is 980 km, with the shortest/longest fiber
link equal to 300 km/2400 km, respectively. We
have generated 10 random matrices with 400
lightpath demands. The histogram of Fig. 5a
depicts the mean number of regenerators at
each node as well as the mean number of lightpaths transiting through each node. Although
confidence intervals are not plotted in this figure, we have noticed that different traffic matrices with the same density result in light
fluctuations in regenerator placement. This
drives us to suggest that network topology
rather than traffic distribution affects regenerator’s placement. It seems that the nodes with
the highest physical degree and highest average
distance to their first neighbors should be
equipped a priori with an electrical regenerator’s pool. Thus, nodes 6 and 7 are good candidates to be equipped with the largest
regenerator banks. Figure 5b illustrates the
evolution of the global amount of regenerators
vs. the Q-threshold. Intuitively, the higher this
threshold, the higher the number of required
regenerators.
We see that node 6 requires 23 regenerators,
while nodes 2, 4, 16 and 17 need none. The
CAPEX-driven approach is intellectually satisfying since it aims to minimize the global
amount of electrical regenerators in the network. Meanwhile, it partially suits the operator’s expectations in terms of OPEX. Indeed,
electrical regenerators are not sold by the unit
but in pools (e.g., cards with four regenerators
may be found on the market). In addition, electrical regenerators need supervision by technicians of the operator since they are electrically
powered. In general, technicians are not based
at each node of the network, only at the most
important ones. In that sense the OPEX-driven
approach cannot be neglected, with the number
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Shared regenerator’s bank
1
O/E/O
O/E/O
N
O/O/O
OXC
N<M×W
1
1
M
M
Add
Drop
Figure 4. Architecture of a translucent node.
of sites to be supervised reduced in comparison
to a spare electrical regenerator placement
strategy. Ideally, both CAPEX- and OPEXdriven approaches are necessary. To the best of
our knowledge, no investigation has been done
from this perspective. Our laboratory works on
this topic by considering Pareto optimization
techniques.
DYNAMIC IA-RWA
The problem of IA-RWA under dynamic traffic
must distinguish between dynamic predictable
traffic and dynamic stochastic traffic. As underlined in our introduction, predicable traffic
may use IA-RWA algorithms comparable to
those proposed for semi-permanent traffic
since in both cases lightpath provisioning is
computed offline. In this context time-space
correlation between traffic demands can be
exploited in order to optimize network resource
utilization. IA-RWA under dynamic and
stochastic traffic is of a different nature. In that
case IA-RWA relies on dynamic lightpath
establishment (DLE) for which the route and
wavelength of an individual demand are computed on the fly at the instant of demand
arrival [11]. Basically, a shortest path approach
is adopted in considering the available
resources at the instant the demand arrives . In
practice we can consider that a carrier requires
that its clients declare at the instant of generation of a stochastic demand the expected duration and capacity of this demand. Unlike static
IA-RWA, dynamic IA-RWA does not have to
solve the problem of electrical regenerator
placement, but to decide which pre-installed
regenerators must be used to guarantee an
acceptable Q-factor at the destination. In other
terms, during the network planning phase, the
nodes susceptible to hosting the largest regenerator’s banks after static IA-RWA could benefit from an overdimensioning factor to deal
with future dynamic and stochastic traffic. In
our example of Figs. 5 and 6, nodes 6 and 7
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25
Number of paths (/20)
Number of regenerators
90
20
Number of regenerators
80
15
10
70
60
50
40
5
30
0
1
2
3
4
5
6
7
20
8 9 10 11 12 13 14 15 16 17 18
Node number
9
(a)
10
11
Q-factor values
12
13
(b)
Figure 5. Electrical regenerator placement under a CAPEX-driven IA-RWA: impact of the Q-threshold.
MULTIDOMAIN IA-RWA
1
15
12
2
16
18
13
6
5
30
0k
m
3
10
8
17
9
2400 km
4
14
11
7
Figure 6. The NSFNET network with 18 nodes.
could benefit from this overdimensioning. Judicious rules must be used to update the cost of
the links when we apply the shortest path algorithm to a new incoming demand in order to
favor the utilization of the available regenerators. In practice updating of the link cost needs
an extended version of generalized MPLS
(GMPLS) signaling. In [7, 8] two approaches
are compared: the signaling and path computation element (PCE) approaches. It has been
shown in the context of realistic traffic scenarios that the first approach is well suited to
DLE. Meanwhile, it requires GMPLS control
plane extensions. The second approach is
apparently better suited to traffic engineering
and does not require GMPLS control plane
extensions. Nevertheless, it does not seem easily scalable to large backbone networks with
high arrival rates of dynamic and stochastic
traffic demands. In the context of the
DICONET project, the impact of opto-electronic devices’ ageing is viewed as a cause of
traffic rerouting by means of dynamic IA-RWA.
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The concept of island of transparency [9] is a
first approach to facilitate multidomain IARWA in translucent networks. In this case the
nodes at the border between two domains managed by two distinct operators are systematically opaque. Each carrier knows precisely the
QoT inherent to each lightpath entering its
network and arriving from a different domain.
All the nodes of one domain except those
located at the border are transparent and eventually equipped with a pool of electrical regenerators. Thus, any pair of nodes within an
island of transparency may communicate transparently if it is physically possible. At the
opposite end, any traffic demand from a source
to a destination located on two different sides
of the border is systematically subject to electrical regeneration at the border. A second
approach authorizes transparent connections
across a border between two domains. In this
context the evaluation of end-to-end QoT may
be a problem if the two operators are not
equipped by the same vendors. Indeed, QoT
thresholds may differ from one side of the border to the other. A third approach for multidomain IA-RWA could be based on traffic
grooming. In [10] the k-center concept has
been proposed as a clustering algorithm for
hierarchical traffic grooming. The basic idea of
this approach consists of positioning EXC/OXC
multilayer nodes within a domain for both purposes: electrical traffic grooming and electrical
regeneration.
CONCLUSION AND OPEN PROBLEMS
IA-RWA may be seen as a form of cross-layer
design associating QoT considerations from
physics with advanced RWA optimization techniques. We have outlined the important progress
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obtained in recent years in the field of static IARWA. Advances must be carried out in order to
determine a reliable analytical expression of a
global Q-factor, including the largest amount of
linear and nonlinear impairments. This objective
was partially achieved at the end of the
RYTHME national research program funded by
the French Ministry of Industry. Much work
remains to be done in the domain of dynamic
IA-RWA. The DICONET European project is
focused on this problem. It also considers for
the first time the impact of aging devices and
systems in terms of QoT fluctuations. For that
purpose, dynamic and nonintrusive optical network monitoring strategies have to be specified
and evaluated both theoretically and experimentally.
REFERENCES
[1] B. Ramamurthy et al., “Impact of Transmission Impairments on the Teletraffic Performance of WavelengthRouted Optical Networks,” IEEE-OSA J. Lightwave
Tech., vol. 17, no. 10, Oct. 1999, pp. 1713–23.
[2] S. Al Zahr, M. Gagnaire, and N. Puech, “Impact of
Wavelength Assignment Strategies on Hybrid WDM
Network Planning,” IEEE DRCN Conf., La Rochelle,
France, Oct. 2007.
[3] S. Subramanian, M. Azizoglu, and A. Somani, “On Optimal Converter Placement in Wavelength Routed Networks,” IEEE INFOCOM, vol. 1, Apr. 1997, pp. 500–07.
[4] X. Chu, B. Li, and I. Chlamtac, “Wavelength Converter
Placement under Different RWA Algorithms in Wavelength Routed All-Optical Networks,” IEEE Trans. Commun., no. 51, Apr. 2003, pp. 607–17.
[5] M. A. Ezzahdi et al., “LERP: A Quality of Transmission
Dependent Heuristic for Routing and Wavelength
Assignment in Hybrid WDM Optical Networks,” IEEE
ICCCN Conf., Arlington, VA, Oct. 2006.
[6] A. Bogoni and L. Potì, “Effective Channel Allocation to
Reduce Inband FWM Crosstalk in DWDM Transmission
Systems,” IEEE J. Sel. Topics in Quantum Elect., vol. 10,
no. 2, Mar.–Apr. 2004.
[7] E. Salvadori et al., “A Study of Connection Management Approaches for An Impairment Aware Optical
Control Plane,” Opt. Net. Design and Modeling Conf.,
Athens, Greece, May 2007.
[8] P. Castoldi et al., “Centralized Versus Distributed
Approaches for Encompassing Physical Impairments in
Transparent Optical Networks,” Opt. Net. Design and
Modeling Conf., Athens, Greece, May 2007.
[9] E. Karasan and M. Arisolu, “Impact of Wavelength
Assignment Strategies on Hybrid WDM Network Planning,” J. Photonic Network Commun., vol. 3, no. 2,
Feb. 2004
[10] B. Chen, R. Dutta, and G. Rouskas, “Clustering for
Hierarchical Traffic Grooming in Large Scale Mesh
WDM Networks,” J. Photonic Network Commun., vol.
3, no. 2, Feb. 2004.
[11] Y. Pointurier et al., “Cross-Layer Adaptive Routing and
Wavelength Assignment in All-Optical Networks,” IEEE
JSAC, vol. 26, no. 6, Aug. 2008, pp. 32–44.
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Much work remains
to be done in the
domain of dynamic
IA-RWA. The
DICONET European
project is focused on
this problem. It also
considers for the first
time the impact of
devices and systems
ageing in terms of
QoT fluctuations.
BIOGRAPHIES
MAURICE GAGNAIRE (maurice.gagnaire@telecom-paristech.fr)
_____________________
is a professor at TELECOM ParisTech, France, where he
leads a team working on grid networks, optical wireless
access systems, and IA-RWA. He has authored and coauthored several books and numerous papers in these
domains. He is involved in various European and national
research projects. He graduated from INT Evry. He received
his Ph.D. from ENST-Paris and his Habilitation from the
University of Versailles in 1992 and 1999, respectively.
S AWSAN A L Z AHR (sawsan.alzahr@telecom-paristech.fr)
____________________ is
working as a research engineer in the optical networks
research group at TELECOM ParisTech. She graduated from
Damascus University, Syria. She received her M.Sc. and
Ph.D. degrees from TELECOM ParisTech in 2004 and 2007,
respectively. She is mainly working on translucent network
planning with guaranteed quality of transmission.
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MUPBED: A Pan-European Prototype for
Multidomain Research Networks
Jan Späth, Ericsson GmbH
Guido Maier, Politecnico di Milano
Susanne Naegele-Jackson, Friedrich-Alexander University of Erlangen-Nuremberg
Carlo Cavazzoni, Telecom Italia
Hans-Martin Foisel, T-Systems/Deutsche Telekom
Mikhail Popov, Acreo AB
Henrik Wessing, Technical University of Denmark
Mauro Campanella, Consortium GARR
Salvatore Nicosia, Ericsson
Jürgen Rauschenbach, DFN-Verein
Luis Perez Roldan, Telefonica I+D
Miguel Angel Sotos, RedEs
Maciej Stróy.k, Poznań Supercomputing and Networking Center
Péter Szegedi, Magyar Telekom
Jean-Marc Uze, Juniper
ABSTRACT
1
The acronym adopted by
the partner inside the project, when used below in
this article, is here reported in brackets.
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Integration and full interoperability are challenging areas of research in wide area networks
today. A European project, MUPBED, has
recently concluded and achieved the main result
of integrating and demonstrating technologies
and network solutions that enable the operation
of future European research infrastructures
capable of supporting advanced applications.
The achieved results are largely valid for any
multidomain network scenario. The test network
set up by the project is a prototype multidomain
optical network able to provide connectivity on
demand services across multiple domains directly driven by the applications. Rather than implementing ex novo a unified control plane and
replacing existing equipment, the project
approach has been to enable seamless interworking of different control planes by means of
ASON/GMPLS and standardized network interfaces. This was done in accomplishment of the
project target, which was to test and trial a common migration path toward the future European
research network that should be followed by
national research and education network operators, together with commercial operators. This
article describes the main aspects of the
MUPBED experience, which by its own peculiar
nature provides deep insight into the most recent
0163-6804/09/$25.00 © 2009 IEEE
evolution of control-plane-enabled optical networking toward multidomain integration. Topics
covered by the project and briefly related here
include network architecture, applications, protocol and control software development, standardization issues, design, analysis and simulation,
testing, measurement, and monitoring.
INTRODUCTION
Integration of different network domains in such
a way as to allow interworking and cross-domain
service provisioning is currently one of the
“hottest” topics still open in optical networking.
To effectively approach this issue it is important
to understand the context (domains, operators,
differences), clarify the motivations (connections, applications), and propose solutions (control plane) as much as possible in compliance
with currently available and evolving standards
and currently deployed technologies.
The European research project Multi-Partner
European Testbeds for Research Networking
(MUPBED) successfully pursued all these goals.
The project of the Sixth Framework Programme
(FP6) Information Society Technologies (IST)
Priority of the European Commission, active from
July 2004 to September 2007, counted 15 partners, comprising equipment manufacturers (Ericsson, Juniper), commercial network operators
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(T-Systems of Deutsche Telekom [DT],1 Telecom
Italia [TI], Telefónica I+D [TID], Magyar
Telekom), National Research and Education Network (NREN) operators (DFN-Verein, GARR,
RedEs, PSNC), and research institutions (Technical University Denmark [DTU], Acreo, University
of Erlangen-Nuremberg [FAU], Politecnico di
Milano) from eight European countries.
The goal of this article is to describe MUPBED’s
successful approach and the “migration path”
toward multidomain interworking in optical networks proposed by the project and practically
proven by the implementation of a working test
network, comprising five individual test-beds interconnected across Europe. The challenge of the project was to operate in the context of the European
research infrastructure focusing on an automatically
switched optical network (ASON) and generalized
multiprotocol label switching (GMPLS) as control
plane integration technologies.
The next section provides an overview of the
MUPBED context: research networks in Europe,
driving applications, and standardization. We
then describe the control plane solution proposed by MUPBED and the innovations brought
by the project to horizontal and vertical integration, in comparison to alternative solutions. The
following section is dedicated to the realized test
network, and the interoperability analyses and
demonstrations performed. We then summarize
the achievements and experiences of the project
in terms of guidelines that may be useful to the
telecommunications industry in general to
increase the degree of integration and interoperability of optical transport networks.
viduality per domain will be maintained in the
foreseeable future; therefore, interworking in
the data and control planes will remain a key
topic.
Today, this interworking is solved for the IP
layer, where global reachability is ensured. However, interworking is still a largely unsolved issue
when it comes to lower network layer technologies such as Ethernet transport or optical circuits,
including
synchronous
digital
hierarchy/optical network (SDH/SONET) connections. Such lower layer connections, however,
are key for many applications and network services demanding high bandwidth and high quality connections. Figure 1a shows a typical
situation in which network domains with different data plane technologies can be interconnected by exploiting user-network interfaces (UNIs)
and external network-network interfaces (ENNIs) that allow the exchange of signaling and
routing information on the ASON/GMPLS control plane level.
MUPBED aimed at developing and investigating several solutions suitable for this networking context. Figure 1b shows the five testbeds of
MUPBED, distributed across Europe, based on
different network technologies, and how these
testbeds have been interconnected on the control plane level. This network prototype exactly
matches the key characteristics of the heterogeneous research network environment in Europe,
and therefore proved to be a valuable test environment to validate feasible interworking solutions. More details on this test network will be
given in the next sections.
NETWORKING CONTEXT
CONNECTIVITY REQUIREMENTS FOR
ADVANCED APPLICATIONS
THE MULTIDOMAIN SCENARIO OF
RESEARCH NETWORKING AS AN EXAMPLE OF A
MULTIDOMAIN ENVIRONMENT
Communications today are not constrained into
a single homogeneous network environment, but
span multiple administrative and technological
domains, often with large differences between
them. The high complexity of realizing end-toend communication services, however, must
remain invisible to end users. Seamless interworking between domains is therefore a key
issue for the networking community.
This becomes especially obvious in the European research network, as in many network scenarios around the globe. In Europe research
networks are organized and structured as shown
in Fig. 1a. Campus networks, research institutions, and selected national and European
research projects are interconnected to the
respective national research network (NREN)
enabling nationwide interconnectivity. In addition, they provide access to the European
research backbone network GÉANT2
(www.GEANT2.net), operated by DANTE,
enabling European-scale connectivity and long
haul connections to research networks outside
Europe. All these networks are completely independent of each other and consequently based
on different network architectures, technologies,
functions, vendor equipment, and network control/management. This heterogeneity and indi-
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In optical networking, all aspects
related to multidomain control and
interoperability
become extremely
important in the
presence of
applications which
require optical
multi-domain
on-demand
connectivity between
remote users.
In optical networking, all aspects related to multidomain control and interoperability become
extremely important in the presence of applications that require optical multidomain on
demand connectivity between remote users. A
detailed understanding of application requirements and their possible interactions with
dynamic networks is mandatory to derive suitable solutions. Therefore, MUPBED investigated the network requirements imposed by a
selection of highly demanding research applications.
The MUPBED applications were grouped
according to their features and the kind of data
involved, which impose specific requirements on
the networks. To have different representatives
of applications with a variety of typical network
requirements, the following case scenarios were
selected:
• Standard- (SD) and high-definition (HD)
uncompressed video transmission for distributed and interactive video productions,
imposing very strict timing constraints on
networks
• Data storage backup and restore, characterized by high bandwidth as well as high security demands
• High quality (HQ) multipartner videoconferencing, chosen as a representative of
applications demanding multicast connections.
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To other network domains
E-NNI
STM-xx
Any future-proof
solution in this area
needs to be standard
Campus
#a
compliant. MUPBED
contributed to the
Project
#z
Campus
#d
from standardization,
focusing on a very
GEANT 2
UNI
SDH or OTN
NREN #3
Ethernet
F
NREN #2
IP
Campus
#b
STM-xx
Project
#x
UNI
GE/10GE
GE/10GE
Project
#y
BEMaGS
Project
#1
UNI
STM-xx
investigation of
emerging solutions
UNI
NREN #1
IP
A
NREN #4
Ethernet
Campus
#c
(a)
close alignment of
latest standards with
the implementations
Acreo
GMPLS
(IP/MPLS)
in the project.
PSNC
Ethernet
UNI
XC
UNI
TID
IP/MPLS
E-NNI
TI
ASON
XC
UNI
DT
ASON
UNI-C 2.0 Ethernet proxy
server implementations
(b)
Figure 1. a) Feasible interworking architecture within the European research network scenario; b)
MUPBED test network scheme.
STANDARDIZATION
For seamless interdomain interworking, properly
defined control plane interdomain interfaces are
needed, linking multiple transport network
domains together via E-NNIs and enabling customers with UNI links to signal on demand service requests directly to the domain with which
they are connected. Customer initiated connections — so-called switched connections — cross
multiple transport network domains. Any futureproof solution in this area needs to be standard
compliant. MUPBED contributed to the investigation of emerging solutions from standardization,
focusing on very close alignment of the latest standards with the implementations in the project.
At the beginning of the MUPBED project, the
first draft specifications for SDH-based Optical
Internetworking Forum (OIF) UNI 1.0 Release 2
and E-NNI 1.0 were available [1]. Prototype
implementations were experimentally evaluated in
the first OIF Worldwide Interoperability demonstration, comprising seven carrier laboratories and
15 system vendors from Asia, the United States,
and Europe. In these interoperability tests and
public demonstrations at SuperComm 2004,
MUPBED partners (Ericsson, TI, DT) and parts
of the test network were involved. For the first
time, interdomain control plane functions were
demonstrated, building the basis for dynamic connection provisioning over multiple SDH domains.
Additionally, interoperability at the data plane
level of International Telecommunication Union —
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Telecommunication Standardization Sector (ITUT) [2] standard-compliant Ethernet-over-SDH
adaptations (GFP, LCAS, VCAT) were evaluated
with MUPBED participation in this OIF event,
building the basis for further development of UNI
2.0 Ethernet control plane functions, enabling Ethernet on demand services over multiple domains,
which were extensively used in 2006 and 2007.
EVOLUTION TOWARD A
SEAMLESS NETWORK
MUPBED performed a thorough analysis of current research networks around the globe to
define the basic characteristics of a suitable
seamless network solution. As a result, the investigations focused on a multilayer network based
on IP/MPLS and ASON/GMPLS technologies,
equipped with a control plane and designed to
support the highly demanding applications that
will be used by the European research community, such as high quality video communication,
storage networking, computing, and data grids.
The project identified the application scenarios relevant to the European research communities. Moreover, the requirements for the network
infrastructure within these scenarios were identified, covering, for example, levels of performance and quality of service (QoS), flexibility
and ease of provisioning, and integration of network control with the application management
functions (see Deliverable D1.1 in [3]). Network
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The implemented
Application plane
ASON solution
Video
conf
Content/
storage
HQ
video
maintained the
Grid
individual
architecture and
Application network interface
technology approach
Control plane
Overlay approach
Packet layer CP
Circuit layer CP
GMPLS peer-to-peer approach
Control
plane
management
in each of the five
testbeds while
enabling automatic
Management
plane
Data plane
end-to-end
interworking among
Packet
layer
Circuit
layer
IP/MPLS
IP/MPLS
the domains.
Ethernet
Ethernet
SDH
OTH
Lambda
Data
plane
management
Fiber
MUPBED multi-service transport network
Figure 2. MUPBED architecture framework.
resilience and protection mechanisms were
implemented and experimented with locally in
the testbeds composing the MUPBED test network (see Deliverable D3.5), but not trialed on
the multidomain scale. Nevertheless, control
plane solutions proposed by the project have
been conceived to be easily upgradable to support resilience through possible future development, and such features have been investigated
in theoretical studies and simulations carried out
by the project (see Deliverable D1.2 in [3]).
Based on these starting points and the results of
the experimental activities, MUPBED defined the
architectural reference model shown in Fig. 2. This
architecture was the basis for the experimental
activities in the multidomain test network, and it
was proposed to the European research networking
community as an evolution of both the GÉANT2
pan-European backbone and the interconnected
NRENs. It should be noted that this architecture is
generally valid for many multitechnology, multidomain network scenarios. In order to allow an
increased level of interaction between application
and network, and enrich the suite of services that
could be offered to users, MUPBED also analyzed,
developed, implemented, and tested various
approaches to efficient realization of application-tonetwork interfaces (details in Deliverables D1.2,
D1.4, D2.2, D2.3, D2.4, and D2.5 in [3]).
THE MUPBED MULTIDOMAIN SOLUTION
The MUPBED network scenario, as already
shown in Fig. 1b, comprised five individual
domains based on IP/MPLS, Ethernet, SDH,
GMPLS, and ASON/GMPLS technologies, and
network control. Given this network environment, the project aimed at providing solutions
that could easily be mapped to European
research networks.
There is no single homogeneous global control
plane solution possible for the research and education networks, given the multiplicity of technologies
involved, their rapid but different developments,
the scale of the environment, and their administrative independence. Nonetheless MUPBED identified and implemented key technologies enabling
seamless interdomain communication that could be
further developed and standardized.
The implemented ASON solution maintained
the individual architecture and technology
approach in each of the five testbeds (therefore
representing the independent network realization
of European NRENs) while enabling automatic
end-to-end interworking among the domains. A
detailed description of the test network and the
accomplished experiments can be found in Deliverables D3.2, D3.3, D3.4, and D3.5 in [3].
In order to enable any kind of client (e.g.,
campus or NREN network element) to get
access to an ASON/GMPLS network and make
use of its functions, a UNI-C proxy server was
developed and integrated in the test network
(dots in Fig. 1b). This UNI-C proxy server provided communication between any upper layer
application requesting path provisioning and the
ASON/GMPLS control plane, especially in the
context where client network elements did not
implement an OIF UNI (Fig. 3a). The UNI-C
proxy server proved to be a feasible and highly
desirable enabler for interdomain interworking
and on demand services. It greatly increased the
value and usability of new control plane capabilities, facilitating the integration of applications
with the network control layer. The proxy implementation was based on an open source solution
(http://sourceforge.net/projects/rsvp-agent/).
APPLICATION-NETWORK INTEGRATION
A close interworking between applications and
dynamic networks is a key element for the success of flexible optical networks. However, in
this area many issues are still unsolved, and for
many aspects standardized solutions are still
missing. MUPBED contributed to this field by
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UNI-C
proxy server
A close interworking
between applications
CP
and dynamic
UNI-N
UNI-C
UNI-N
networks is a key
Client
DP
DP
element for the
success of flexible
E-NNI
UNI
optical networks.
UNI
(a)
However, in this area
many issues are still
Uncompressed
HD video
unsolved, and for
many aspects
solutions are still
API
API
missing.
Adaptation
function
Adaptation
function
UNI
UNI
Network
domain 1
HQ video
conference
Content and
storage
standardized
Network service requestor
API
Network service provider
Network
domain 2
Translation of requirements
and resource allocation
UNI-proxy (UNI-C)
E-NNI
UNI
UNI-N
(b)
(c)
Figure 3. a) UNI-C proxy server usage for non-control plane enabled devices and network elements; (b)
MUPBED adaptation function located outside the UNI; (c) translation of application requests to signaling
messages.
2
A preliminary version
was presented in [4].
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developing and investigating several solutions,
proving in demonstrations the feasibility of the
proposed mechanisms.
The MUPBED network provided a UNI to
the client networks or users. However, most
applications do not communicate on a UNI level;
thus, the advantages of a dynamic transport network are reduced. The applications require a
higher level of abstraction from the network
layer protocols (e.g., Resource Reservation Protocol with Traffic Engineering [RSVP-TE] or
Constraint-Based Routing Label Distribution
Protocol [CR-LDP]). Hence, an adaptation function (AF)2 was introduced, responsible for interfacing with the network control plane and
deciding when new network resources from the
(optical) circuit layer should be established. The
AF, which is shown in Figs. 3b and 3c, received
resource requests from the applications and was
responsible for triggering resources in the transport network. In this way a decoupling between
the applications and the specific transport technology was ensured. The AF did not consider the
network topology as it was only aware of the
edge-to-edge connections that were associated
with the UNI-C instance it controlled.
The applications, acting as clients, communicated with the AF through an application programming interface (API), which was
implemented as a Web service. The main objective of the API was to provide the applications
with uniform access to the adaptation function
completely decoupled from any RSVP signaling
or knowledge of the underlying transport technology.
Three main communication messages were
defined:
• Resource request was used to initiate a new
packet connection from the application to
the adaptation function. Unless the
resource was requested “now,” the request
was stored in the adaptation function, and
the status was polled using the status
request message. The resource request
message provided a handle or ID for the
connections.
• Resource release was used to terminate a
packet layer connection defined by the handle.
• Status request was used to request the status
of a connection for monitoring purposes
and to see for future connections if the traffic parameters were satisfied.
The main parameters included in the resource
request issued for a given connection were traffic
parameters (e.g., the QoS level); requested start
and end time; and priority of the connection,
defined in terms of pre-allocation and deadline
parameters (defined in Deliverable D2.2 [3]).
The only modification that needed to be
implemented on the application side was the network service requester (NSR) component, which
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communicated through the API with the network
service provider (NSP) on the AF side. The
resource allocation function was responsible for
registering resource requests and allocating the
resources when the connection should be established. Finally, the AF integrated the UNI proxy,
which was responsible for network signaling.
The AF was implemented in three different
versions, each with specific objectives and functionalities:
• The direct socket stack
• The graphical user interface (GUI) stack
• The network provider stack (NPS)
The direct socket stack was basically the UNI
proxy for applications requesting services directly from this stack. It provided the lower interface
for the other two versions.
The NPS used the API and UNI specified in
MUPBED. In addition, it included a QoS transport control layer, which communicated with
other NPS-enabled network domains to support
bandwidth allocation. This was detailed in Deliverables D2.4 and D2.5 [3]. The storage and
videoconferencing applications were integrated
with the NPS version.
The objective of the standalone or GUI stack
was to provide a user interface for users with applications that could not easily be integrated with the
API. Examples were commercial applications,
where the source code was not available. In such
cases this stack provided a GUI where the application operator could manually request the resources
on behalf of the application. The client communicated with the AF through a Web services interface, thus solving most firewall issues. The GUI
stack was used to provide bandwidth to the SD/HQ
video applications, since it allowed provisioning of
network resources in connection with commercial
encoding and decoding hardware.
Using the GUI stack, it was possible for a
commercial application like SD/HD video transmissions to reduce manual connection setup
times of weeks or months to minutes or seconds,
which increased the flexibility offered to the
application. The same results could be demonstrated using the NSP version in the case of the
storage applications for requesting connections
prior to large data transfers.
In summary, the application integration with
the ASON/GMPLS models significantly
improved the performance of the applications
with respect to setup times, transmission quality,
and so on. On the other hand it greatly increased
the value of control plane solutions for optical
networks.
OTHER APPROACHES
Worldwide, other solutions have been proposed
during MUPBED’s lifetime for multidomain on
demand services implementation and evaluation,
partly based on ASON/GMPLS control planes.
In the following the most relevant of such solutions are listed; the results of those activities
available during MUPBED were taken into
account and extended by the MUPBED project.
The European-wide NOBEL2 project [5] set
up a multidomain ASON/GMPLS demonstrator
including ASON-GMPLS domain signaling interworking, comprising real and emulated network
elements. Alternatively, the PHOSPHORUS
project focused on applying GMPLS solutions to
grid application environments [6], whereby the
GÉANT2/JRA3 [7] project investigated piloting
of on demand services based on middleware
domain and interdomain managers for the European NREN community.
The German VIOLA project [8] set up a
national ASON/GMPLS test network for SDH
and Ethernet on demand services for bandwidth
demanding applications. Intensive joint VIOLAMUPBED interoperability evaluations, demonstrations, and disseminations were accomplished.
In the United States the DRAGON and
HOPI projects [9] implemented GMPLS control
plane functions in test networks, paving the road
for on demand service implementations in the
Internet2 network [10].
In some carrier networks, on demand services
were also deployed (e.g., AT&T “optical mesh
services”; see AT&T’s presentation at ECOC
2006 Workshop in [3]), Verizon Just-in-Time
(JIT) Provisioning Service [11], and research
networks such as GÉANT2 in Europe [7] and
SINET3 in Japan [12].
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To provide a basis
for assessing
solutions for heterogeneous network
environments,
MUPBED set up a
multi-layer and multidomain European
test network comprising five individual
domains based on
IP/MPLS, Ethernet,
SDH, GMPLS,
ASON/GMPLS technologies, and network control.
TESTING, DEMONSTRATION, AND
ANALYSIS
NETWORK IMPLEMENTATION AND OPERATION
To provide a basis for assessing solutions for
heterogeneous
network
environments,
MUPBED set up a multilayer and multidomain
European test network comprising five individual domains based on IP/MPLS, Ethernet, SDH,
GMPLS, and ASON/GMPLS technologies, and
network control. Figure 4 provides a topological
layout of the test network environment, illustrating the five testbeds and the additional sites at
DTU and FAU providing applications, including
their Ethernet over IP/MPLS interconnections
crossing the NRENs and GÉANT2. These test
networks were carefully selected in order to have
a significantly heterogeneous multidomain network environment as a starting point, comprising
all the main and most deployed transport network technologies.
The overall roadmap of MUPBED was to
first establish data plane interconnections among
all local testbed sites and afterward add
ASON/GMPLS control plane interdomain functions so that in the end an integrated data and
control plane enabled seamless interworking of
these domains, forming a European-scale test
network infrastructure.
In a first step, layer 2 (Ethernet over
IP/MPLS) static connections over the NRENs
and GÉANT2 were established among all five
local testbeds (Fig. 4), enabling basic data plane
connectivity. Even this step required multiple
data plane solutions for mapping procedures
among the different technologies used in the
involved network domains:
• LSP stitching of different Ethernet over
IP/MPLS vendor implementations at the
GÉANT2-NREN interfaces.
• At each testbed location the IP/LSPs were
mapped into Ethernet VLANs.
• Within each local MUPBED testbed, an
Ethernet VLAN resolution followed.
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Layout of MUPBED network
A significant effort in
MUPBED was
Northern Europe
testbed
dedicated to
demonstrate its
Acreo
User
community
multi-domain
solution described
PSNC
Acreo TB
Eastern Europe
testbed
PIONIER
above to external
NORDUnet
communities in order
DTU
to highlight its
effectiveness as a
research networks.
Central Europe
testbed
FAU
Western Europe
testbed
service platform
supporting future
T-Systems
T-Systems TB
GEANT2
UPC
User
community
DFN
User
community
Red.es
TID TB
TID
GARR
Telecom Italia
TB
Ericsson/
Marconi
TB: Test Bed
Ericsson/
Marconi
Laboratories
xyz
Academic
xyz
Private R&D
Networks
IP + ASON/GMPLS
Telecom
Italia
User
community
IP + WDM + 10GE + MPLS
IP + 10GE
IP + 10GE + WDM
Southern Europe
testbed
IP/MPLS
Figure 4. MUPBED European test network topology.
• The configuration of the test network was
done by switching functions in the SDH
domains (Ethernet-over-SDH mapping) at
the local testbed sites of TI and DT.
Finally, the ASON/GMPLS interdomain interworking functions were implemented according to
the OIF specifications (Fig. 1b). These activities
included the implementation of a UNI-C 2.0 Ethernet proxy agent at PSNC, its functionality, performance, and interoperability tests, and finally its
additional implementations at Acreo, TID, and
DT, as well as FAU and DTU, followed by final
performance evaluations. This European-scale,
multidomain, and multilayer ASON/GMPLS test
network was the basis for numerous experimental
demonstrations and evaluations (e.g., measuring
end-to-end QoS parameters, both at the network
and application layers), as well as collaborations
with research communities and external projects
(e.g., setting up connection monitoring and control plane monitoring tools).
In the last three months of the project duration, the OIF interdomain interfaces were updated
according to the latest OIF specifications, and the
main components were tested on a global scale in
the framework of the OIF Worldwide Interoperability Demonstration 2007 [1]. With this effort
the MUPBED network achieved what is currently
still the highest level of global interoperability.
INTEROPERABILITY DEMONSTRATIONS
A significant effort in MUPBED was dedicated to
demonstrating its multidomain solution, described
above, to external communities in order to highlight its effectiveness as a service platform supporting future research networks. Special emphasis
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was dedicated to the organization of public
demonstrations and the selection of the proper
test network configurations for these events, based
on the experimental results from both the networking and application related activities.
As one example, the full control plane interworking functionality of the MUBED network
was demonstrated at the TERENA Networking
Conference held in Copenhagen in May 2007.
The control plane topology used at the conference is shown in Fig. 5a.
The UNI 2.0 Ethernet proxy servers installed
at the edges of the partner domains Acreo,
PSNC, and TID enabled the setting up and tearing down of on demand Ethernet connections
(bandwidth-on-demand service) in the partners
DT and TI. The same proxy servers were used
by the partners DTU and FAU for signaling to
the DT domain and setting up/tearing down Ethernet connections using the MUPBED-developed application-network interworking software
(standalone GUI/API-adaptation function). This
made it possible to provision the link DTUAcreo-DT-FAU (over a distance of about 2000
km) via the DT domain directly from the conference booth. The control plane connection was
established using an IPSec tunnel in the public
Internet. The established link was used to transmit live uncompressed video of about 400 Mb/s
in both SD and HD quality from FAU to the
conference booth (see a snapshot of the transmission in the inset of Fig. 5a). Between DT and
TI the provisioned connection was set up by
using E-NNI; thus, all UNI and E-NNI links of
the MUPBED test network were in operation at
the conference. The live establishment of the
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MUPBED
DTU
application
Acreo
GMPLS
(IP/MPLS)
TID
IP/MPLS
OIF
UNI2.0
Ethernet
OIF
UNI2.0
Ethernet
TI
ASON
XC
UNI-C 2.0 Ethernet
proxy server
OIF
E-NNI
UNI proxy
PSNC
Ethernet
OIF
UNI2.0
Ethernet
OIF
UNI2.0
Ethernet
IP/MPLS
UNI-C 2.0 Ethernet
MUPBED proxy
DT
ASON
OIF
UNI2.0
Ethernet
FAU
application
Ethernet
UNI-C 2.0 Ethernet
MUPBED proxy
UNI-C 2.0 Ethernet
MUPBED proxy
UNI-C UNI-C
UNI-C UNI-C
proxy 3 proxy 1 proxy 2 proxy 5
SSR2
XC
(GMPLS)
IP/MPLS
SSR1
MSH-64c MSH-64c
M2
M1
MSH-64c
M3
MSH-64c MSH-64c
M2
M1
MSH-64c
M3
UNI-C 2.0
Ethernet
proxy 6
UNI
proxy
FAU
(b)
(a)
Figure 5. a) Control plane topology of the MUPBED test network at the TERENA Networking Conference 2007; b) multiple simultaneous provisioned Ethernet connections DTU-DT-FAU + PSNC-DT + TID-TI-DT-Acreo and TI-DT.
connections was visualized with tracking software (a snapshot is shown in Fig. 5b, solid and
dashed green lines).
A detailed description of all MUPBED
demonstrations can be found in Deliverables
D4.2, D4.4, and D4.5 in [3].
EVALUATION OF MORE COMPLEX SCENARIOS
Theoretical network models, simulators, and
emulators allowed MUPBED to investigate further multi-domain scenarios beyond the size or
the functionality of the test network (including
network resilience, setup of protected connections on demand, grid applications [4]). The
example briefly reported here is dedicated to
routing, an important still open issue in multidomain optical-networks.
According to ITU-T ASON Recommendations [2] different routing policies may be adopted to distribute routing information between the
domains. MUPBED carried out a scalability vs.
performance comparison of the different ASONcompliant policies under dynamic traffic, simulating the case study of a multidomain network
as represented in Fig. 6a (a simplified version of
GÉANT2 plus the five NRENs involved in
MUPBED). Results of the analysis are reported
in full detail in Deliverable D1.2 [3] and were
presented at ECOC 2007 [13]. Routing performance was measured by computing the average
blocking probability of connections as a function
of traffic load, assuming dynamic traffic of connection requests modeled as Poisson traffic. Policy scalability was evaluated by estimating the
amount of routing information disseminated
throughout the network. In the graphs of Fig. 6
such an amount is indicated by the normalized
parameter I, the ratio between the amount of
routing information implied by each specific policy allowed by ASON and the amount if the
whole network is regarded as a single domain
(dotted curves in the graphs).
Interdomain blocking (Fig. 6b) reflects ranking
of policies according to I: the higher the value of
I, the lower the blocking probability. On the other
hand, low-I policies, for which interdomain con-
nections tend to be “killed” in overload conditions, imply that more free resources are available
for intradomain routing. This is revealed by the
intradomain plot (Fig. 6c), where higher blocking
probabilities correspond to high values of I. In
general, however, the smaller the amount of
information available for routing, the more inefficient the network utilization can be (Fig. 6d).
This study testifies that interdomain routing
is a complex problem involving different interests potentially in conflict. For example, a global
administrator of the overall multidomain infrastructure (e.g., a European institution sponsoring a pan-European research network) would
prefer routing approaches that allow efficient
use of network resources. Conversely, a single
domain administrator would prefer limited propagation of routing information that does not
increase its intradomain blocking. Solutions to
this problem need a common agreement among
all the involved parties. Obviously conclusions
cannot be generalized to any possible interdomain scenario, but the example studied is significant as it is representative of the current
European research network infrastructure, as
well as the common situation of a long-distance
carrier interconnecting regional-size operators.
CONCLUSIONS
The MUPBED work allowed smooth interconnection of multiple transport domains and manifold customer/client network domain
technologies (ASON, IP/MPLS, GMPLS, Ethernet) with minimized operational efforts over
standard control plane interfaces.
The results proved that ASON/GMPLS functionalities provide benefits at different levels:
they ease network management, allow fast ondemand service provisioning to support high
bandwidth applications, and facilitate multidomain and multilayer interworking. ASON/
GMPLS control plane functionalities help solve
interoperability issues among different network
administrators thanks to the standardized
UNI/E-NNI interfaces. In addition, a differentia-
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Figure 6. Comparison of ASON multidomain routing policies: a) case-study network; results in terms of b) inter- and c) intradomain
blocking probability; d) results of network utilization.
tion of service classes can be provided over different layers in multilayer networks by routing
best effort traffic at the IP layer, while using
optical pipes for IP traffic aggregation and highquality optical shortcuts for a subset of services.
In order to allow any kind of client to get
access to ASON/GMPLS networks, especially in
the context where commercial data equipment
does not implement an OIF UNI, a UNI-C 2.0
Ethernet proxy server was developed and
assessed. This proxy server greatly increased the
value and usability of the ASON/GMPLS control plane capabilities. In the application-network interworking area, standardization
activities are very limited, and a closer link
between the control plane standardization and
applications-middleware-network management
communities is needed. Therefore, MUPBED
introduced an adaptation function as a mediating layer between the applications and the network control plane. This adaptation function,
offering a simple-to-use API to the applications,
provided a technological decoupling between
the application and network, but still allowed
for tight client-server registration and provisioning of network resources corresponding to the
applications. The two different approaches
implemented (the first relying on the API network service requester, the second exploiting a
standalone GUI when application code is not
adaptable) provide an excellent solution for a
vast range of applications with strict QoS
requirements (e.g., high quality video,
telemedicine). Such applications are able to
benefit from the high bandwidth and perfor-
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mance offered by an optical transport network,
as MUPBED measurements clearly showed.
The results described in this article and the
guidelines provided by the project were primarily
derived for the European research network environment, but are widely applicable to similar
networks such as Internet2 or any heterogeneous
scenario of national and international networks,
where services are currently manually configured
and a single homogeneous global control plane
approach is not feasible. With this prototype
solution, MUPBED proved the suitability of
ASON/GMPLS as an enabler for future dynamic
networks, supporting highly demanding applications across multiple domains.
ACKNOWLEDGMENT
This work was partly funded by the European
Commission under frame contract FP6-511780.
The authors thank all the members of the project consortium and all further partners for their
co-operation and support.
REFERENCES
[1] Optical Internetworking Forum; www.oiforum.com
[2] ITU Publications; http://www.itu.int/publications
[3] All MUPBED deliverables and public documents;
http://www.ist-mupbed.eu
[4] P. Szegedi, Z. Lakatos, and J. Späth, “Signaling Architectures and Recovery Time Scaling for Grid Applications in IST Project MUPBED,” IEEE Commun. Mag., vol.
44, no. 3, Mar. 2006, pp. 74–82
[5] R. Muñoz et al., “Experimental Demonstration of ASONGMPLS Signaling Interworking in the NOBEL2 MultiDomain Multi-Layer Control Plane Emulator,” Proc. Int’l.
Conf. Optical Net. Design Modeling, Mar. 12–14, 2008,
pp. 1–6; http://www.ist-nobel.org/Nobel2
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[6] G. Zervas et al., “Phosphorus Grid-Enabled GMPLS Control Plane (GMPLS): Architectures, Services, and Interfaces,” IEEE Commun. Mag., vol. 46, no. 6, June 2008,
pp. 128–37; http://www.ist-phosphorus.eu
[7] “Deliverable DJ.3.3.1: GEANT2 Bandwidth on Demand
Framework and General Architecture;” http://www.
geant2.net/upload/pdf/gn2-05-208v7_dj3-3-1_GEANT2
_Initial_Bandwidth_on_Demand_Framework_and_
______________________________
_________
Architecture.pdf.
[8] P. Kaufmann, “VIOLA-Testbed: Current State and First
Results,” Proc. Terena Net. Conf., Catania, Italy, June
2006; http://www.viola-testbed.de/
[9] Xi Yang et al., “GMPLS-Based Dynamic Provisioning and
Traffic Engineering of High-Capacity Ethernet Circuits in
Hybrid Optical/Packet Networks,” Proc. IEEE INFOCOM
’06, April 23–29, 2006, pp. 1–5.
[10] A. Stone, “Internet2’s breakthroughs for academic
research,” IEEE Distrib. Sys. Online, vol. 5, no. 1, 2004;
http://www.internet2.edu
[11] S. S. Liu et al.: “Deployment of Carrier-Grade Bandwidth-on-Demand Services over Optical Transport Networks: A Verizon Experience,” OFC/NFOEC ’07, paper
NThC3.
[12] I. Inoue et al., “GMPLS based Multi Layer Service Network Architecture for Advanced IP over Optical Network Services in Japan,” Proc. ECOC ’08, Sept. 21–25,
2008, pp. 1–2; http://www.sinet.ad.jp
[13] G. Maier, F. Mizzotti, and A. Pattavina, “Multi-Domain
Routing Techniques in ASON Networks,” Proc. ECOC
’07, Sept. 2007, Berlin, Germany.
BIOGRAPHIES
JAN SPÄTH [M] (jan.spaeth@tesat.de)
___________ received his Ph.D. from
the University of Stuttgart, Germany, in 2002. In 2001 he
joined Marconi, later acquired by Ericsson, where he led a
team working on network evolution for transport and data
networks. He has been working in several funded projects
and was appointed project coordinator for the IST project
MUPBED. In 2008 he joined Tesat-Spacecom, where he leads
a test department for satellite subsystems. He is a member
of VDE ITG, and has been appointed as an expert of the
European Commission to review FP7 research projects.
G UIDO M AIER (maier@elet.polimi.it)
____________ received his Laurea
degree in electronic engineering and his Ph.D. degree in
telecommunications in 1995 and 2000, respectively, both
from the Politecnico di Milano, Italy. Through February
2006 he was a researcher and head of the Optical Networking Laboratory at CoreCom In March 2006 he joined
Politecnico di Milano as an assistant professor. His main
interests are optical network optimization, multidomain
ASON/GMPLS, and photonic switching systems. He is the
author of more than 70 papers in international journals
and conferences in the area of optical networks. He has
been or is involved in several research projects, including
BONE, EuroFG, MUPBED, and NOBEL2.
SUSANNE NAEGELE-JACKSON (Susanne.Naegele-Jackson@rrze.
_________________
uni-erlangen.de)
________ graduated with a Master’s degree in computer science from Western Kentucky University and the University of Ulm, Germany. She received her Dr.-Ing. from the
University of Erlangen-Nuremberg in computer science. She
has worked at the Regional Computing Center of the same
university since 1998 on a variety of national and internationaly research projects such as GTB, Uni-TV, Uni-TV2, VIOLA,
EGEE-III, and MUPBED. She has authored and co-authored
over 30 scientific pulbications, and teaches classes on multimedia networking at the Regional Computing Center.
CARLO CAVAZZONI (carlo.cavazzoni@telecomitalia.it)
_________________ received
his Dr.Ing. degree in electronic engineering from Politecnico di Torino in 1992. Since 1994 he has worked at Telecom
Italia Lab (formerly CSELT). During the past few years he
has been involved in several European research projects
such as the IST projects NOBEL and MUPBED, working on
the definition and experimental evaluation of innovative
network solutions and technologies for intelligent and flexible optical networks. He is the author of several technical
papers in the field of optical networking.
HANS-MARTIN FOISEL (Hans-Martin.Foisel@t-systems.com)
___________________ is
head of the Hybrid Technology Department in the Technical Engineering Center at Deutsche Telekom Netwok Production. Currently he serves as President and Chair of the
Carrier Working Group of the OIF. At Deutsche Telekom his
work is focused on multilayer and multidomain networks:
their architectures, functions, standardization, and interoperability aspects. Prior to joining Deutsche Telekom, he
worked at the Heinrich Hertz Institute, Berlin, Germany, for
19 years on R&D of optical transmission systems. He holds
a diploma in electrical engineering from the University of
Kassel and Technical University of Berlin.
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MIKHAIL POPOV (mikhail.popov@acreo.se)
_____________ received his Ph.D.
degree in electromagnetic theory in 2002 from the Royal
Institute of Technology (KTH), Stockholm, Sweden. He
joined Acreo as a research scientist and project manager in
2001. His current research interests include next-generation
access and in-building networks, Ethernet, and
ASON/GMPLS. He is the coordinator for the Large-Scale
Integration Project ALPHA, Architectures for Flexible Photonic Home and Access Networks, and Chair of the Converged and Optical Networks cluster of the Future Network
projects in EC Framework Programme 7.
H ENRIK W ESSING (hw@com.dtu.dk)
_________ worked as a research
assistant in the Networking Competence Area at Research
Center COM (now DTU Fotonik) after completing his Master’s degree, and in 2001 he began his Ph.D. studies on
electronic control of optical infrastructures and components. In this project control electronics for controlling
devices and network architectures were specified and
implemented in FPGAs. In the European IST project DAVID
he participated in the development of the experimental
demonstrator, and as WP leader in IST-MUPBED, he coordinated the integration of applications with the optical infrastructure. In addition, he developed FPGA-based control
electronics for controlling 10 Gb links for a major industrial
partner.After completing his Ph.D., he continued at
COM . DTU (now DTU Fotonik)with responsibility for the
coordination, maintenance, and development of research
activities related to the experimental platform. Currently he
is also involved in the European project ALPHA coordinating DTU’s activities, and as WP leader for demonstration
activities for the Danish Advanced Technology Foundation
sponsored project HIPT.
F
The results proved
that ASON/GMPLS
functionalities
provide benefits at
different levels: they
ease network management, allow fast,
on-demand service
provisioning to support high bandwidth
applications, and
facilitate multidomain and multilayer interworking.
MAURO CAMPANELLA (Mauro.Campanella@garr.it)
_______________ graduated
in physics in 1985; since then, his main work has been
related to computing and networking. Currently he works
for the Italian National and Education Network (GARR)
where he is a main engineer responsible for research activities. He is one of the creators of the premium IP QoS service of the European NREN network backbone GÉANT and
created the architecture of the bandwidth-on-demand service of GÉANT2. He acts as coordinator of the FEDERICA
project.
SALVATORE NICOSIA’S (salvatore.nicosia@ericsson.com)
_________________ biography was not available as this issue went to press.
J ÜRGEN R AUSCHENBACH ’ S (jrau@dfn.de)
_______ biography was not
available as this issue went to press.
LUIS PEREZ ROLDAN’S (lperez@tid.es)
_______ biography was not available as this issue went to press.
MIGUEL A NGEL S OTOS ’ (miguel.sotos@rediris.es)
_____________ biography
was not available as this issue went to press.
.
M ACIEJ S TROY K (mackostr@man.poznan.pl)
_______________ received an
M.Sc. degree in computing science from the Poznań University of Technology, Poland, in 2003. His research interests focus on optical networks, network management, and
multimedia streaming systems. Since 2003 he has been
working as a system designer/analyst and programmer for
the Network Department of the Poznań Supercomputing
and Networking Center.
P ÉTER S ZEGEDI (szegedi.peter3@t-com.hu)
______________ is currently the
JRA2 and NA2 leader of the FEDERICA project. He received
his M.Sc. degree in electrical engineering at Budapest University of Technology and Economics, Hungary, in 2002. He
then worked toward a Ph.D. in the Department of Telecommunications of that university.His main research interests
include design and analysis of dynamic optical networks,
especially optical Ethernet architectures, network control,
and management processes.He worked for Magyar Telekom
from 2003 to 2007, involved in the MUPBED project, and
then joined TERENA in January 2008.
__________ biography was not
J EAN -M ARC U ZE ’ S (juze@juniper.net)
available as this issue went to press.
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Toward Efficient
Failure Management for Reliable
Transparent Optical Networks
Nina Skorin-Kapov, University of Zagreb
Ozan K. Tonguz, Carnegie Mellon University
Nicolas Puech, Télécom ParisTech
ABSTRACT
Security and reliability issues are of utmost
importance in transparent optical networks due
to the extremely large fiber throughput. Fast and
successful reaction and restoration mechanisms
performed by failure management can prevent
loss of large amounts of critical data, which can
cause severe service disruption. In this article we
discuss failure management issues in TONs, the
mechanisms involved, and optical monitoring
techniques. Furthermore, we propose applying
structural properties of self-organizing systems
to create a “small world” hybrid supervisory
plane that can enable faster system-wide communication. We also investigate the possibility of
a scale-free structure aimed at improving robustness in the network and propose various topology generation algorithms.
INTRODUCTION
The rapid growth of data traffic, primarily Internet traffic, in the past several years is driving the
demand for high-speed communication networks. Optical networks based on wavelengthdivision multiplexing (WDM) have been
established as the most promising solution for
satisfying the ever increasing capacity requirements in telecommunication networks. WDM is
a technology that can exploit the large potential
bandwidth of optical fibers by dividing it among
different wavelengths. Transparent optical networks (TONs) are dynamically reconfigurable
WDM networks that establish and tear down alloptical data connections, called lightpaths,
between pairs of nodes. These connections can
traverse multiple links in the physical topology,
and yet transmission via a lightpath is entirely in
the optical domain. The reliability of such networks is critical since a single failure can cause
tremendous data loss. Although transparency
has many attractive features, such as speed and
insensitivity to data rate and protocol format, it
introduces several vulnerabilities to security.
Optical performance monitoring is much more
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difficult since it must be performed in the optical domain.
A failure management system is used to deal
with failures in the TON, which could be due to
either component faults or deliberate attacks
that aim to disrupt the proper functioning of the
network. Due to the transparency inherent in
TONs, nodes do not have access to service-bearing wavelengths except where data lightpaths
terminate. Thus, management and control information is carried over a separate supervisory
wavelength that is optoelectronically processed
at each node [1]. We refer to this interconnection of supervisory channels as the supervisory
plane. In case of failure, failure management
receives alarms from the monitoring equipment
available (via the supervisory plane), and then
attempts to locate and isolate the source. Meanwhile, the source and destination nodes of failed
lightpaths are notified of the failure, after which
they launch their restoration mechanisms. In this
article we propose creating a hybrid supervisory
plane whose structure is such that it can speed
up and improve critical security information
exchange, and thus improve the network’s ability
to reconfigure and reestablish communication in
the presence of failures. We propose adding a
set of long-range supervisory lightpaths in addition to the point-to-point channels between
physically neighboring nodes, aimed at creating a
small-world scale-free topology.
The small-world and scale-free properties are
structural properties that have been observed in
many self-organizing complex systems. Self-organizing systems are those in which local low-level
interactions and processes between individual
entities spontaneously achieve global properties
with certain functionality. Since structure affects
function, these systems often self-organize into
structures which enable efficient and successful
operation. We propose applying these concepts
to TONs in order improve the efficiency of failure management in them. This is a first step in
applying self-organization to optical networks.
Our ultimate goal, and vision for the future, is to
develop a self-healing and self-management
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approach that will be able to supervise the functioning of TONs in the presence of increasing
complexity and unforeseen attacks.
The rest of this article is organized as follows.
In the next section we discuss failure management and optical monitoring in TONs. Complex
network structures are then discussed. We propose a new hybrid optical supervisory plane and
topology generation algorithms. We then discuss
numerical results, and finish with some concluding remarks and ideas for future work.
FAILURE MANAGEMENT ISSUES IN
TRANSPARENT OPTICAL NETWORKS
FAILURE MANAGEMENT
Failure management in TONs deals with the
countermeasures taken to compensate for vulnerabilities in the network and failures that can
occur. Failures can be due to component faults
and deliberate attacks on the proper functioning
of the TON. Component faults include single or
multiple component malfunctions that can be a
consequence of natural fatigue, improperly
installed or configured equipment, or external
influence (e.g., power loss). Attacks, on the other
hand, are deliberate attempts to interfere with
the secure functioning of the network. Attacks
differ from faults in that they can spread and
propagate throughout the network and can
appear sporadically. These characteristics make
them much harder to locate and isolate. Various
attacks have been described in [2, 3]. They most
often include jamming and/or tapping legitimate
data signals by exploiting component weaknesses
such as gain competition in optical amplifiers
and crosstalk in switches.
The countermeasures taken by failure management to ensure secure network operation
include prevention, detection, and reaction
mechanisms [2]. Prevention schemes can be realized through hardware (e.g., strengthening
and/or alarming the fiber), transmission schemes
(e.g., coding schemes), or network architecture
and protocols. Detection mechanisms are
responsible for identifying and diagnosing failures, locating the source, and generating the
appropriate alarms or notification messages to
ensure successful reaction. Due to attack propagation capabilities and the constraints inherent
in optical performance monitoring, these tasks
are more difficult than in electrical networks.
Various alarms generated by monitoring equipment, changes in performance trends, and customer call-ins all help to detect failures.
The third aspect of failure management is
reaction to failures. Reaction mechanisms restore
the proper functioning of the network by isolating the failure source, reconfiguring the connections, rerouting, and updating the security status
of the network. In order to establish, tear down,
and reroute lightpaths in the presence of major
traffic changes, new connection requests, and/or
unexpected failures, a control plane employing
various signaling and routing protocols is maintained in the TON [4]. In case of attacks it is
crucial that reaction mechanisms quickly isolate
the source to preclude further attacks. Survivability techniques, which are responsible for
restoring failed lightpaths, utilize either preplanned backup paths or reactive rerouting
schemes [5]. Both techniques require that the
source and destination nodes of failed lightpaths
be informed of the failure quickly to ensure high
restoration speeds.
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Failure management
mechanisms are
highly dependent on
alarms received from
OPTICAL PERFORMANCE MONITORING
optical monitoring
Failure management mechanisms are highly
dependent on alarms received from optical monitoring equipment. Optical monitoring devices
that are currently available include optical power
meters, optical spectrum analyzers, OTDRs, eye
monitors, and others [6]. These devices help
monitor passing signals and send alarms if they
detect certain suspicious behavior. Various optical monitoring equipment can be used to detect
certain failures, but by no means all of them. For
example, optical power meters (which monitor
changes in the power of an optical signal) can
detect component faults or overt in-band jamming, but may not detect sporadic jamming.
Some optical monitoring techniques can estimate the bit error rate (BER) without electronically processing the data payload. These methods
include using subcarrier multiplexed pilot tones
or evaluating histograms derived from eye diagrams. Additionally, some optical components
can have monitoring capabilities themselves
(e.g., transmitters may send an alarm if their
temperature exceeds a given threshold). An
excellent survey of optical monitoring techniques
can be found in [7]. Due to the high cost of such
equipment, it is not realistic to assume all nodes
are equipped with full monitoring capabilities.
Thus, obtaining monitoring information from
nodes with high monitoring capabilities efficiently is critical for successful failure management.
equipment. Optical
monitoring devices
which are currently
available include
optical power
meters, optical
spectrum analyzers,
OTDRs, eye monitors, and others.
STRUCTURAL PROPERTIES OF
SELF-ORGANIZING
COMPLEX SYSTEMS
Until the middle of the 20th century, complex
systems were modeled using regular topologies
and Euclidian lattices. After the pioneering work
of Erdös and Rényi in the 1950s, random graphs
became predominant. However, many real-world
self-organizing networks, from the collaboration
of film actors to biological ecosystems, lie somewhere between order and randomness. These
complex networks have been successfully
described using the small-world [8] and scalefree [9] models developed in the 1990s. In order
to describe these models in more detail, we first
define the basic parameters most often used to
characterize complex network structures. They
are:
• The average path length L: The average
hop distance between all pairs of nodes.
• The clustering coefficient C: The typical
cliquishness of a local neighborhood. For
each node, we find the ratio of edges in its
immediate one-hop neighborhood (including itself) to the total possible number of
edges in this neighborhood. These values,
averaged over all the nodes in the network,
define the clustering coefficient C.
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(a)
(b)
Figure 1. An example of a) a small-world network generated using the WS
small-world generation procedure from [8] where 0 < p << 1; b) a scale-free
network.
• The degree distribution P(k): The probability that a randomly selected node has exactly
k neighbors.
SMALL WORLDS
Small-world networks are highly clustered (like
lattices), and yet have low average path lengths
(like random networks). Watts and Strogatz [8]
proposed a rewiring method, which we refer to
as the WS algorithm, to generate small-world
graphs that can be tuned to lie at various points
between regular and random graphs. The algorithm initially starts with a ring lattice and then
randomly replaces, or rewires, existing links with
random ones with probability p. If p is set to 0,
the network remains regular. For a probability
of p =1, a random graph is created. It has been
shown that even for very small p (i.e., a tiny bit
of rewiring), the procedure dramatically lowers
the average path length with respect to that of a
regular lattice, and yet does not significantly
affect the clustering coefficient. Thus, a small
world is born. An example of a small-world network generated in this manner is shown in Fig.
1a. Such small worlds have Poisson degree distributions that peak at an average degree and then
decay exponentially.
The realization that a small world can easily
be created by introducing just a few shortcuts
between cliques could prove advantageous in the
context of communication networks [10]. Namely, applying these concepts has the potential to
improve information flow and propagation speed
in the Internet, ad hoc networks, and possibly
TONs. Intuitively, high-speed shortcuts between
distant parts of a network could enable faster
system-wide communication, thus aiding dynamic processes such as synchronization, control,
and management.
SCALE-FREE NETWORKS
The characteristic property of scale-free networks is their power law degree distribution.
This basically means that there are a few nodes
with many neighbors and many nodes with just a
few neighbors. An example of a scale-free topology is shown in Fig. 1b. The high-degree nodes
are referred to as hubs and basically hold the
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network together. Barabasi, Albert, and Jeong
[9] showed that such power law properties can
emerge from stochastic growth and preferential
attachment. Basically, as a network grows, new
nodes tend to connect to already well connected
nodes (the so-called rich get richer phenomenon)
and thus self-organize into a scale-free state.
They propose an algorithm to generate such a
network, called the BA algorithm, which initially
starts with just a small number of interconnected
nodes (m0). Each new node connects to m < m0
existing nodes, where the probability of connecting to a node is proportional to its degree. Scalefree networks have been shown to be highly
robust against accidental failures, but very sensitive to coordinated attacks. Hence, attacking
only a few key hub nodes could devastate the
entire system, while random failures rarely have
a significant effect.
A HYBRID SUPERVISORY PLANE FOR
SECURE TONS
THE PROPOSED SUPERVISORY PLANE
We would like to explore whether the scale-free
and small-world models could help to design a
more robust TON. We investigated certain smallworld characteristics in [11] and further elaborate on them here. Unfortunately, applying these
structural models to TONs is not straightforward. If we consider the physical interconnection
of optical fibers, which is more lattice-like and
clustered due to geographical considerations,
utilizing the WS “rewiring” mechanism to
achieve a small world is simply not realistic.
Rewiring random edges would involve major
cost concerns related to digging and laying down
new fiber. Furthermore, physical optical networks do not grow continuously at a significant
rate since most fiber plants have already laid
down large amounts of extra fiber that has not
yet been lit for use by Internet service providers
and other users of bandwidth. When such networks do grow, fibers and/or nodes are added at
locations that best suit the owner of the fiber
plant, whose goal is to improve network performance as a whole and not the selfish needs of
the newly added node. Thus, growth by preferential attachment to create scale-free topologies,
which is the basis of the BA algorithm, may not
be applicable.
However, recall that in TONs all-optical connections called lightpaths create a virtual topology over the underlying physical network. This
topology is much more flexible and can be
dynamically reconfigured, subject to certain constraints. Creating a small-world and/or scale-free
topology of data lightpaths independent of the
physical interconnection of fibers may be possible. However, in the context of failure management, ignoring the physical topology does not
seem logical since optical monitoring information exchange between physical neighbors is crucial. For example, propagating attacks can trigger
a large number of redundant alarms, which can
often be resolved via communication between
physically neighboring downstream and/or
upstream nodes.
We propose creating a hybrid supervisory
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Maintaining high
clustering in the
supervisory plane is
desirable in the context of optical monitoring and security to
help detect false
alarms and resolve
redundant ones.
Point-to-point supervisory
channels
Long-range supervisory
lightpaths
The hybrid supervisory
plane
Figure 2. An example of a hybrid supervisory plane on a reference European core topology.
plane by maintaining the bidirectional point-topoint supervisory channels along each physical
link, but also introducing a few long-range supervisory lightpaths between distant nodes. Thus,
we could create a small-world supervisory plane,
clustered as a result of the physical topology, but
with a low average path length due to the small
number of transparent shortcuts. An example of
such a supervisory plane for a reference European core topology from [12] is shown in Fig. 2.
Communication via these lightpaths would be
somewhat slower than between physically neighboring nodes due to longer propagation delays,
but would still be very fast as a result of their
transparency. In addition to the small-world
property, these shortcuts could be arranged to
yield a scale-free topology that could possibly
help create a more robust supervisory plane.
MOTIVATION
The main motivation for creating a small-world
supervisory plane is to speed up the exchange of
monitoring and control information, particularly
in the context of failure management. Our goal
is to ensure that the management system
receives monitoring alarms and messages as
quickly as possible to ensure fast failure detection and localization. Furthermore, we aim to
speed up the process of signaling the end nodes
of failed lightpaths to start their restoration procedures quickly before triggering higher-level
restoration and causing severe data loss and
data contention.
Besides the faster exchange of monitoring
information, long-range supervisory lightpaths
could potentially be used to help nodes with
access to local information obtain a better picture of the global network state. In the proposed supervisory plane, “local” information
exchange would also include communication
between distant parts of the network via virtual
shortcuts. Important additional information
could be exchanged and merged with local information obtained from physical neighbors to create a more robust network. This information
could possibly be used to avoid suspicious parts
of the network, help localize attacks, find routes
for reconfiguration purposes more quickly,
and/or share past experiences and preplanned
responses.
Meanwhile, maintaining high clustering in the
supervisory plane is desirable in the context of
optical monitoring and security to help detect
false alarms and resolve redundant ones. Clustered individuals in various self-organizing systems have been known to establish trust easier
and communicate more frequently, and thus
work together more efficiently [13].
Clustered individuals
in various self-organizing systems have
been known to
establish trust easier
and communicate
more frequently.
SUPERVISORY PLANE GENERATION ALGORITHMS
In order to generate a supervisory plane with the
desired structural properties, we investigated the
possibilities of applying various rewiring, preferential attachment, and growth techniques. Topology
generation algorithms for wireless networks were
proposed in [14].
Preliminaries — We refer to the source nodes
of supervisory lightpaths as informants since they
provide the destination nodes with additional
information. It is important to note that not all
nodes are equally attractive to use as informants.
Nodes with access to more information, better
monitoring equipment, and perhaps a good reputation for providing trustworthy and quick
responses may provide more reliable information. We define the attractiveness of a node i as
an informant to be based on a combination of
the following factors:
• The number of data lightpaths that traverse
the node, called transient lightpaths, denoted
DPitr after the data plane. Nodes that have
more lightpaths passing through them will
be able to monitor and analyze more data
connections.
• The node’s optical monitoring capabilities,
denoted Moni.
• The number of data lightpaths terminating
at the node, denoted DPidest. Here the optical data signal is converted into the electrical domain; hence, extensive BER
monitoring can be performed.
• The number of data lightpaths originating
at the node, denoted DP isource . Here, the
node can obtain detailed information
regarding the traffic being sent along these
lightpaths.
• The node’s in-degree in the supervisory
plane, SPiin (i.e., how well informed it is)
• The node’s out-degree in the control plane,
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SP iout , multiplied by a factor F. This is a
measure of the node’s reputation and desirability among other nodes, which is crucial
in growth procedures to enable the rich get
richer phenomenon. Varying parameter F
allows us to tune the effect of this phenomenon to the desired level.
The overall attractiveness of node i, A(i), is
calculated as
3.4
3.2
Phy
RA
PA
R-PAG
O-PAG
L
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2.8
2.6
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0
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PA
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O-PAG
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PA
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O-PAG
0.44
0.42
0.4
0
3
6
9
12
15
18
21
24
27
30
(c)
Figure 3. The average path lengths: a) L; b) Lmon_to_s_and_d; c) clustering of
the supervisory planes generated by the proposed algorithms and the physical
topology for traffic type 1.
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A(i)= MoniDPitr + DPiin + DPiout
+ SPiin + FSPiout
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Note that the first element ensures that a
node can only provide information regarding
transient lightpaths if it employs optical monitoring. Otherwise, data lightpaths simply pass transparently through the node. Herein, we propose
four supervisory plane topology generation algorithms:
•The Random Attachment algorithm: The
Random Attachment (RA) algorithm, inspired
by the WS rewiring procedure, considers nodes
in random order and chooses for each a random
informant. The algorithm terminates after a
desired number of shortcuts have been established.
•The Preferential Attachment algorithm:
Instead of randomly choosing informants to
which to attach, considering their attractiveness
could prove beneficial. The Preferential Attachment (PA) algorithm selects nodes at random
and chooses for each an informant with a probability proportional to its attractiveness. Potential
informants are all nodes in the network, except
for those that are physically neighboring the
node choosing the informant since they are
already connected in the supervisory plane via
point-to-point supervisory channels. This process
is repeated until a desired number of long-range
shortcuts are established.
•The Randomized Preferential Attachment via
Growth algorithm: Since most of the supervisory
plane is fixed (i.e., the links corresponding to the
physical topology), all the nodes are already
included in the topology and thus cannot be
grown as in the BA algorithm. However, we can
grow an informant web of supervisory lightpaths
and then superimpose it onto the physical topology to get our hybrid supervisory plane. The
Randomized Preferential Attachment via
Growth (R-PAG) algorithm runs as follows. It
first chooses a set, m 0 , of the most attractive
nodes that are not physical neighbors, and interconnects them in an informant web. The algorithm then randomly selects nodes not yet
included and assigns to each of them m informants from the existing informant web (provided
they are not physical neighbors) with a probability proportional to their attractiveness. This differs from the PA algorithm in that potential
informants are only those nodes already included in the informant web. After a desired number
of long-range shortcuts are assigned, the algorithm terminates, and the directed informant
web is merged with the physical topology to
form the supervisory plane.
•The Ordered Preferential Attachment via
Growth algorithm: Since the informant web
grown by the R-PAG algorithm may not include
all nodes (depending on the desired number of
shortcuts), it may prove beneficial to not only
select informants according to their attractiveness, but also select the nodes that choose informants according to their attractiveness. The
Ordered Preferential Attachment via Growth
(O-PAG) algorithm, like R-PAG, begins by
interconnecting m0 of the most attractive nodes.
The algorithm then iteratively selects the most
attractive node not included in the informant
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1
for each a random
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informant. The
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algorithm terminates
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have been
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established.
(a)
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after a desired
number of shortcuts
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procedure, considers
nodes in random
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16
21
5
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19
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28
2
23
10
25
22
7
27
7
(c)
(d)
Figure 4. Sample informant web topologies with 30 shortcuts for traffic type 1 generated by the a) RA; b)
PA; c) R – PAG; (d) O – PAG algorithms.
plane and assigns to it m informants from the
existing informant web (provided they are not
physical neighbors) with a probability proportional to their attractiveness. The informant web
is then superposed onto the physical topology.
NUMERICAL RESULTS
In order to assess the potential benefit of the
proposed failure management model and topology generation algorithms, we implemented these
four algorithms in C++ and tested them on a
reference pan-European topology from the
COST Action 266 project [12] with 30 nodes and
48 bidirectional edges. To create a set of data
lightpaths, we generated traffic matrices where a
fraction F of the traffic is uniformly distributed
over [0, C/a], while the remaining traffic is uni-
formly distributed over [0, C * d/a] as in [15].
Here, C represents the lightpath channel capacity, a is an arbitrary integer greater than or equal
to 1, and d represents the average ratio of traffic
intensities between node pairs with high and low
traffic values. We ran 25 test cases for three different types of traffic: Traffic type 1 had the values set to C = 1250, a = 20, d = 10, and F =
0.7, as in [15]. Traffic type 2 considered all traffic to be uniformly distributed over the same
value (d = 1 and F = 1), while traffic type 3 had
mostly uniformly distributed traffic, but with a
few very long bursts (d = 100 and F = 0.95).
Lightpaths were then established on the shortest
paths between pairs of nodes in decreasing order
of their corresponding traffic, with at most five
lightpaths originating and terminating at each
node.1 Monitoring capabilities were assigned to
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100
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10-1
10-2
100
101
k
102
10-1
10-2
100
(a)
101
k
102
(b)
Figure 5. The out-degree distributions of the supervisory planes generated by the a) R-PAG; (b) O-PAG algorithms by superposing the
informant webs from Fig. 4 onto the physical topology.
1
We assumed that there
were enough available
wavelengths on all links.
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nodes according to the monitoring placement
policy described in [16]: if a node is non-monitoring, all its neighbors must be monitoring
nodes. Furthermore, if a node is of degree one,
its neighboring node must be a monitoring node.
We ran the proposed algorithms for all test
cases with the desired number of shortcuts ranging from 0 to 30, in increments of three, assuming that each node could be assigned a maximum
of one informant. In the growth algorithms, RPAG and O-PAG, m0 was set to 2 and m was set
to 1. Various values for F in the attractiveness
function were tested. The results shown in Figs.
3, 4, and 5 are those with a = 10.
For each test case, we recorded the average
path length, L, and the clustering coefficient, C.
Since the clustering coefficient is defined on an
undirected graph, the supervisory lightpaths
were considered undirected in the calculation of
C. Furthermore, we found the average path
length in hops from each monitoring node to the
source and destination nodes of all data lightpaths passing through it averaged over all the
monitoring nodes in the network. We refer to
this as Lmon_to_s_and_d. This is a measure of how
fast an alarm can get from a monitoring node to
the corresponding end nodes of failed lightpaths
to signal that they are to launch their restoration
mechanisms. The results, averaged over the 25
test cases for traffic type 1, are shown in Fig. 3.
The results are compared with the standard
supervisory plane composed of only point-topoint supervisory channels along all physical
links, denoted Phy. Results for traffic types 2
and 3 are analogous, and are thus omitted for
lack of space.
We can see from Figs. 3a and 3b that a significant decrease in the average path lengths L and
Lmon_to_s_and_d are already achieved by assigning
informants to only 10–30 percent of the nodes,
adding only 3–9 long range lightpaths to the
fixed 48 bidirectional physical links (i.e., 96
directed point-to-point supervisory channels).
Further increasing the number of informants
seems inefficient due to the increase in overhead
and resources used, as well as the decrease in
clustering. When comparing the clustering coefficients in Fig. 3c, we can see that for a small
number of informants, a high level of clustering
is maintained. In fact, the ordered growth procedure O-PAG actually increased the clustering
coefficient for cases with up to 18 extra lightpaths.
In order to determine the kind of patterns
generated by the proposed algorithms, we plotted the interconnection of supervisory lightpaths for a large number of informants. An
example with 30 lightpaths is shown in Fig. 4. It
is evident that the growth algorithms (Figs. 4c
and 4d) generate topologies more hierarchical
in nature, centered around certain hub nodes.
Figure 5 shows the corresponding degree distribution of the supervisory planes generated by
the growth algorithms. We can see from the
graphs that they are fairly close to following a
power law. Although this property may not be
very pronounced for a small number of informants, supervisory lightpaths are still centered
around a small number of the most attractive
nodes. A potential advantage of having such
hub nodes in the supervisory plane is robustness to random failure, although it may increase
vulnerability to attacks on hubs. Fortunately,
hub nodes in our hybrid supervisory plane generated via R-PAG or O-PAG are mainly those
with the best monitoring equipment due to the
attractiveness function and thus are inherently
better protected.
CONCLUSIONS AND FUTURE WORK
As a result of the increasing complexity of transparent optical networks and the tremendous
amount of information they carry, efficient failure management is crucial. While transparency
offers many advantages, it also imposes various
vulnerabilities in optical network security. Selforganizing concepts could possibly be applied to
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develop a highly scalable and robust failure
management scheme. Commonly observed
structural properties in many self- organizing
networks can be described by the small-world
and scale-free models. In this article we propose
using these models to develop a more efficient
supervisory plane to deal with failure management in transparent optical networks. A smallworld scale-free supervisory plane could
significantly speed up monitoring information
exchange and potentially improve reliability. We
propose various topology generation algorithms
and show how they can achieve the desired
structure. After establishing such a supervisory
plane, several things will need to be considered
in order to design an efficient self-organizing
failure management architecture, which is our
ultimate goal. Future work will include embedding individual nodes with sufficient intelligence
aimed at migrating failure management from its
currently centralized form to a more distributed
self-organizing approach. This will include
developing individual node behavior protocols,
defining the content of local information
exchange , and introducing mechanisms to
establish trust between nodes.
ACKNOWLEDGMENTS
The work described in this article was carried
out with the support of the BONE project
(Building the Future Optical Network in
Europe), a Network of Excellence funded by the
European Commission through the 7th ICTFramework Programme, research project 0360362027-1641, funded by the Ministry of Science,
Education and Sports of the Republic of Croatia, and the HONeDT Cogito Project supported
by the Croatian and French governments.
REFERENCES
[1] M. W. Maeda, “Management and Control of Transparent Optical Networks,” IEEE JSAC, vol. 16, no. 7, 1998,
pp. 1008–23.
[2] M. Médard et al., “Security Issues in All-Optical Networks,” IEEE Network, vol. 11, no. 3, 1997, pp. 42–48.
[3] N. Skorin-Kapov, O. Tonguz, and N. Puech, “Self-Organization in Transparent Optical Networks: A New
Approach to Security,” 9th Int’l. Conf. Telecommun.,
invited paper, Zagreb, Croatia, 2007, pp. 7–14.
[4] G. Li et al., “Control Plane Design for Reliable Optical
Networks,” IEEE Commun. Mag., vol. 40, no. 2, 2002,
pp. 90–96.
[5] M. Sivakumar, R. K. Shenai, and K. M. Sivalingam, “A
Survey of Survivabilty Techniques for Optical WDM Networks,” Ch. 3, Emerging Optical Network Technologies:
Architectures, Protocols and Performance, K. M.
Sivalingam and S. Subramaniam, Eds., Springer Science+Media, Inc., 2005, pp. 297–332.
[6] C. Mas, I. Tomkos, and O. Tonguz, “Failure Location
Algorithm for Transparent Optical Networks,” IEEE
JSAC, vol. 23, no. 8, 2005, pp. 1508–19.
[7] D. C. Kilper et al., “Optical Performance Monitoring,” J.
Lightwave Tech., vol. 22, no. 1, 2004, pp. 294–304.
[8] D. J. Watts and S. H. Strogatz, “Collective Dynamics of
‘Small-World’ Networks,” Nature, vol. 393, 1998, pp.
440–42.
[9] A.-L. Barabasi and R. Albert, “Emergence of Scaling in Random Networks,” Science, vol. 286, 1999, pp. 509–12.
[10] J. J. Collins and C. C. Chow, “It’s a Small World,”
Nature, vol. 393, 1998, pp. 409–10.
[11] N. Skorin-Kapov and N. Puech, “A Self-Organizing
Control Plane for Failure Management in Transparent
Optical Networks,” Proc. IWSOS ’07, LNCS 4725, 2007,
pp. 131–45.
[12] R. Inkret, A. Kuchar, and B. Mikac, “Advanced Infrastructure for Photonic Networks: Extended Final Report
of COST Action 266,” Faculty Elec. Eng. and Comp.,
Univ. of Zagreb, 2003, pp. 19–21.
[13] M. Buchanan, Nexus: Small Worlds and the Groundbreaking Theory of Networks, W. W. Norton, 2002, pp.
199–204.
[14] S. Dixit, E. Yanmaz, and O.K. Tonguz, “On the Design
of Self-Organized Cellular Wireless Networks,” IEEE
Commun. Mag., vol. 43, no. 7, July 2005, pp. 76–83.
[15] D. Banerjee and B. Mukherjee, “Wavelength-Routed
Optical Networks: Linear Formulation, Resource Budgeting Tradeoffs, and a Reconfiguration Study,” IEEE/ACM
Trans. Net., vol. 8, no. 5, 2000, pp. 598–607.
[16] T. Wu and A. Somani, “Cross-Talk Attack Monitoring
and Localization in All-Optical Networks,” IEEE/ACM
Trans. Net., vol. 13, no. 6, 2005, pp.1390–1401.
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Future work will
include embedding
individual nodes with
sufficient intelligence
aimed at migrating
failure management
from its currently
centralized form to a
more distributed
self-organizing
approach.
BIOGRAPHIES
NINA SKORIN-KAPOVIS (nina.skorin-kapov@fer.hr)
______________ is an assistant professor at the University of Zagreb, Faculty of Electrical Engineering and Computing, Croatia. She received
her Dipl.-Ing. (2003) and Ph.D. (2006) degrees in electrical
eengineering from the same university, and completed a
post-doctoral fellowship at Télécom Paris — École Nationale
Supérieure des Télécommunications, France from September 2006 to September 2007. Her main research interests
include optimization in telecommunications (particularly in
WDM wide-area optical networks), optical networks planning, and security.
O ZAN K. T ONGUZ (tonguz@ece.cmu.edu)
____________ is a tenured full
professor in the Electrical and Computer Engineering
Department of Carnegie Mellon University (CMU). He currently leads substantial research efforts at CMU in the
broad areas of telecommunications and networking. He
has published about 300 papers in IEEE journals and conference proceedings in the areas of wireless networking,
optical communications, and computer networks. He is the
author (with G. Ferrari) of Ad Hoc Wireless Networks: A
Communication-Theoretic Perspective(Wiley, 2006). His current research interests include vehicular ad hoc networks,
wireless ad hoc and sensor networks, self-organizing networks, bioinformatics, and security. He currently serves or
has served as a consultant or expert for several companies,
major law firms, and government agencies in the United
States, Europe, and Asia.
NICOLAS PUECH (npuech@enst.fr)
_________ graduated from the École
Nationale Supérieure des Télécommunications (Télécom
ParisTech), Paris, France, in 1987 as a telecommunications
engineer. He received a Ph.D. degree in computer science
(honors) in 1992 from the University of Paris 11 and the
Habilitation in computer science and networks from the
University of Paris 6 (2007). He joined TELECOM ParisTech
as an associate professor in 2002. His research interests
include network planning and modeling, optimization, and
computer algebra. He is a co-author of over 40 papers in
journals and international conferences. He has published
several books as an author or a translator. He is editor of
the IRIS book series published by Springer Verlag.
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SERIES EDITORIAL
THE FIRST ITU-T KALEIDOSCOPE EVENT:
“INNOVATIONS IN NGN”
Yoichi Maeda
T
Mostafa Hashem
Sherif
he Feature Topic of this issue is about the first International Telecommunication Union — Telecommunication Standardization Sector (ITU-T) Kaleidoscope
event that took place in Geneva, Switzerland on 12–13
May 2008. This was an academic conference on “Innovations in NGN (Next Generation Networks)” that brought
together over 220 participants from 48 countries, including
students and professors from 43 academic institutions.
In organizing this conference, the goals of the ITU-T
were to increase collaboration among academia and
experts working on the standardization of information and
telecommunications technologies (ICTs) to identify possible applications of the NGN that may require standardization. The conference was technically co-sponsored by the
IEEE Communications Society, and the Proceedings are
now available electronically via IEEE Xplore. Cisco Systems donated a total of US$10,000 for the three best paper
awards (respectively $5000, $3000 and $2000). Other sponsors were Intel, the International Communications Foundation (ICF) of Japan, and Sun Microsystems.
A total of 141 papers were submitted and underwent a
double-blind peer review process. Each proposal received
at least three full paper reviews. The three best papers
were selected from nine nominations following the presentation of all papers, and a number of young authors were
recognized. The awards recipients were:
• First prize: “Architecture and Business Model of
Open Heterogeneous Mobile Network,” by Yoshitoshi
Murata, Mikio Hasegawa, Homare Murakami, Hiroshi
Harada, and Shuzo Kato
• Second prize: “Differential Phase Shift Quantum Key
Distribution” by Hiroki Takesue, Toshimori Honjo,
Kiyoshi Tamaki, and Yasuhiro Tokura
• Third prize: “Open API Standardization for the NGN
Platform” by Catherine Mulligan
The keynote speech was given by Professor Myung Oh,
President of Konkuk University, Korea, on the importance
of research and development (R&D) and its socio-economic implications, and the need to balance profit-driven
industry and innovation-led academia in standardization.
Mr. Alexander D. Gelman, Director of Standards, IEEE
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Communications Society, gave a keynote presentation on
IEEE standards and future collaborations between the
ITU-T and the IEEE in the area of standardization. Three
papers were invited for each track of the conference. For
Track 1, this paper was “A New Generation Network —
Beyond NGN” by Professor Tomonori Aoyama, Research
Institute for Digital Media and Content, Keio University,
Japan. Track 2’s invited paper was by Dr. Martin Körling
from Ericsson on “Evolution of Open IPTV Standards and
Services.” The invited paper for track 3 was “Open Standards: A Call for Action” by Mr. Ken Krechmer, University of Colorado.
This issue of the Standards Series contains updated versions of the winning papers and two of the three invited
papers. The first article, “A New Generation
Network:Beyond the Internet and NGN” by Tomonori
Aoyama, describes the requirements and fundamental
technologies to provide a new generation network beyond
the Internet and the next generation network (NGN), both
of which are based on IP protocols. Although the Internet
has grown into a social infrastructure, and the NGN is
expected to replace both legacy telephone networks and
cellular phone networks in the near future, there are many
technological, economic, and societal factors pushing the
search for revolutionary network technologies and a cleanslate designed architecture beyond the IP structure.
The second article, “Open Standards: A Call for
Change” by Ken Krechmer, reviews the different needs of
specific groups of society and develops 10 different requirements for open standards. Digital communications is both
pervasive and vital across society. This creates growing
public interest in the technical standards that proscribe
public communications. While there is public demand for
“open standards,” this rallying cry means different things
to different groups. To implement these requirements,
changes to the rules and procedures of standardization
organizations, international bodies, and national patent
office rules are proposed. Interestingly, technical changes,
in the form of new standardized protocols rather than legal
or policy changes, appear to be the most important to
meet the requirements of open standards.
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The third article, “The Architecture and a Business
Model for the Open Heterogeneous Mobile Network” by
Yoshitoshi Murata, proposes revised architectures for
TISPAN-NGN that correspond to heterogeneous networks
and open mobile markets, and present new business models. The mobile communications market has grown rapidly
over the past 10 years, but the market may reach saturation in the foreseeable future. More flexible mobile networks able to meet various user demands and create new
market openings are needed for further growth. Heterogeneous networks are more suitable than homogeneous networks for meeting a wide variety of user demands. There
are two types of heterogeneous network: a closed type
whose network resources are deployed and operated by
communication carriers, and an open type whose network
resources would be deployed not only by existing operators
but also by companies, universities, and so on. It will be
easy for newcomers to enter mobile businesses in an open
heterogeneous mobile network, so many innovative services are likely to be provided through cooperation
between various companies or organizations.
The fourth article, “Differential Phase Shift Quantum
Key Distribution” by Hiroki Takesue, describes quantum
key distribution (QKD), which has been studied as an ultimate method for secure communication and is now emerging as a technology that can be deployed in real fiber
networks. The authors present their QKD experiments
based on the differential phase shift QKD (DPS-QKD)
protocol. A DPS-QKD system has a simple configuration
that is easy to implement with conventional optical communication components, and is suitable for a high clock
rate system. Moreover, although the DPS-QKD system is
implemented with an attenuated laser source, it is inherently secure against strong eavesdropping attacks called
photon number splitting attacks, which pose a serious
threat to conventional QKD systems with attenuated laser
sources. It also describes three types of single photon
detectors that are suitable for high-speed long-distance
QKD: an up-conversion detector, a superconducting single
photon detector, and a sinusoidally gated InGaAs
avalanche photodiode. The article presents the record setting QKD experiments that employed those detectors.
The last article, “Open API Standardization for the
NGN Platform” by Catherine Mulligan, offers outlines the
importance of open APIs, what currently exists in the standards bodies, and concludes with a brief set of issues standards bodies need to resolve in relation to these APIs.
NGNs are meant to enable a richer set of applications to
the end user, creating a network platform that allows rapid
creation of new services. Significant progress has been
made in the standardization of NGN architecture and protocols, but little progress has been made on open APIs.
The Organizing Committee was chaired by Mr. Yoichi
Maeda (NTT, Japan), and the Program Committee was
chaired by Mr. Pierre-André Probst (OFCOM, Switzerland).
He was assisted by Messrs. Mostafa Hashem Sherif (AT&T,
United States), Mitsuji Matsumoto (Waseda University,
Japan), and James Carlo (JC Consulting, United States).
The Guest Editors would like to express their sincere
thanks to all the authors for this Feature Topic, and to the
reviewers for the Kaleidoscope event and for this issue for
their helpful remarks that contributed to the outstanding
quality of the articles. They would like to express their
gratitude to the Editor-in-Chief and production staff for
their strong support.
The second Kaleidoscope academic conference will take
place in Argentina, 31 August–1 September 2009, just
before the NGN-GSI event in the same venue. Additional
information is available at http://www.itu.int/ITU__________________
T/uni/kaleidoscope/2009.
________________
BIOGRAPHIES
YOICHI MAEDA [M] (yoichi.maeda@ntt-at.co.jp)
______________ received B.E. and M.E. degrees
in electronic engineering from Shizuoka University, Japan, in 1978 and
1980, respectively. Since joining NTT in 1980, for the last 26 years he has
been engaged in research and development on access network transport
systems for broadband communications including SDH, ATM, and IP. From
1988 to 1989 he worked for British Telecom Research Laboratories in the UK
as an exchange research engineer. He currently leads the standardization
promotion section in NTT Advanced Technology Corporation and is NTT’s
Senior Adviser on Standardization. In October 2008 at the World Telecommunication Standardization Assembly (WTSA-08), he was appointed to the
chair of ITU-T SG15 for the 2009–2012 study period for his second term. He
is a Fellow of the IEICE of Japan. He has been a feature editor of the Standards Series in IEEE Communications Magazine since 1999.
MOSTAFA HASHEM SHERIF (mhsherif@att.com)
__________ has been with AT&T in various
capacities since 1983. He has a Ph.D. from the University of California, Los
Angeles, an M.S. in management of technology from Stevens Institute of
Technology, New Jersey, and is a certified project manager from the Project
Management Institute (PMI). Among the books he authored are Protocols
for Secure Electronic Commerc (2nd ed. CRC Press, 2003), Paiements électroniques sécurisés, Presses polytechniques et universitaires romandes,
2006, and Managing Projects in Telecommunication Services (Wiley, 2006).
He is a co-editor of two books on management of technology published by
Elsevier Science and World Scientific Publications in 2006 and 2008, respectively, and is the editor of the forthcoming Handbook of Enterprise Integration (3rd ed.), Auerbach. He is also a standards editor for IEEE
Communications Magazine, an associate editor of the International Journal
of IT Standards & Standardization Research, and a member of the editorial
board of the International Journal of Marketing.
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ITU-T KALEIDOSCOPE
A New Generation Network:
Beyond the Internet and NGN
Tomonori Aoyama, Keio University and National Institute of Information and Communications Technology
ABSTRACT
This article describes requirements and fundamental technologies to enable the provision of
a new generation network beyond the Internet
and the next generation network, both of which
are based on IP protocols. Although the Internet
has grown into a social infrastructure and the
NGN will replace legacy telephone networks and
cellular phone networks in the near future, it is
time to start R&D on revolutionary network
technologies and clean-slate designed architecture beyond the IP structure. Here some R&D
activities for a new generation network are
shown. This article is a revised version of the
author’s presentation in the First ITU-T Kaleidoscope Academic Conference [1] held in Geneva last May.
INTRODUCTION
The broadband Internet and third-generation
(3G) cellular phone networks are rapidly expanding, and advanced applications such as content
search, YouTube type image services, SNS, and
Second Life type cyber space applications have
been born and grown up day by day. The world
standards for next generation network (NGN)
are being proceeded in the International
Telecommunication Union — Telecommunication Standardization Sector (ITU-T). The objectives of NGN are to replace legacy telephone
networks using state-of-the-art IP network technologies, and support triple-play and quadrupleplay services over quality of service (QoS)
controllable IP networks. In Japan NTT started
NGN services at the end of March last year [2].
Telecommunications vendors are now concentrated their resources on the deployment of the
NGN systems. Figure 1 shows an image of the
evolution of the commercial communication networks in a few decades, and in the near future
two types of IP-based networks will coexist.
Figure 2 presents some differences in characteristics between the Internet and NGN,
although both are applying IP. One of the most
important characteristics of the Internet is a best
effort bearer function to interconnect multiple
IP packet router-based networks, which means:
• No overall network planning, and no clear
responsibility and common control rule
exist among networks.
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• TCP/IP is the only common rule for connections.
• Users have freedom to install any applications.
In contrast, NGN is considered as an effort to
re-establish QoS control bearer functions to
interconnect multiple networks with clear
responsibility, and three kinds of interfaces: the
user-network interface (UNI), network-network
interface (NNI), and application-network interface (ANI) are defined. NGN applies TCP/IP,
but is not based on the “end-to-end argument,”
which is one of the fundamental principles for
the network architecture of the Internet.
Although in these few decades two types of
IP-based networks coexist, merging legacy nonIP-based networks, it is time to start research on
a future network architecture and protocol
beyond the Internet and NGN. Here this is
called the new generation network (NWGN) to
distinguish it from NGN. NWGN is to have a
clean-slate designed architecture, and is not
intended to improve TCP/IP-based networks.
R&D on a future network with a completely
new architecture has just started globally. For
example, Global Environment for Network Innovations (GENI) [3] and Future Internet Design
(FIND) [4] programs funded by the National
Science Foundation (NSF) have started in the
United States, and the Seventh Framework Program (FP7) [5] by the European Commission
includes some projects similar to NWGN. In the
next section the research on NWGN in Japan is
mainly introduced.
RESEARCH APPROACH FOR NWGN
The history of communication networks tells us
that there have been three paradigms so far:
the telegraph, the telephone, and the Internet.
Each network has a very clear objective. The
telegraph is a network to transmit Morse code
by on-off key terminals over electric current.
The telephone network is to transmit electrical
waveforms made by vocal air vibration. The
Internet is to transmit data between computers.
Three paradigms originally apply only one type
of appliance each to interconnect. It is therefore noted that the appliance to be interconnected determined the network architecture
and main protocols to realize the objective of
the network.
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How about the fourth network paradigm?
Can we identify a major appliance to be interconnected in NWGN? The important difference
from the previous three paradigms is that we
cannot identify a major appliance, and versatile
appliances should be taken into account to determine the network architecture and protocol. Figure 3 shows a scheme to define a new network
architecture through a clean-slate approach, not
through an improvement of current network
architecture. The bottom-up approach, the topdown approach, and the design principle are
equally important, and all the research outputs
from each approach should be merged into one
solution for NWGN architecture and protocol as
a fourth communication network paradigm.
F
Cellular phone network
The Internet
Started
NXGN (NGN)
Future
NWGN
2008
2020
NXGN (NGN): Next generation network
NWGN:
New generation network
The systematic research on NWGN in Japan
started around 2006. In 2006 the Ministry of
Internal Affairs and Communication (MIC)
formed a committee to discuss future network
R&D issues. In the committee the author proposed NWGN as a network beyond the Internet/NGN, which are both based on IP, and
according to the recommendation of the committee, an all-Japan NWGN Promotion Forum
(NWGN Forum) [6] was established in November 2007. Japanese industry cannot afford to
use their large amounts of resources for R&D
on NWGN at this moment due to the NGN
business deployment, so the National Institute
of Information and Communications Technology (NICT) should be at the core of the NWGN
R&D together with the academic community.
NICT set the NWGN Strategic Section to guide
NWGN R&D in Japan, and started the AKARI
Project [4], which is a core research group to
study the NWGN architecture and protocols.
Furthermore, NICT is operating a network
testbed, named JGN2plus [7], and is providing
funding with a competition process to academia
and industry for NWGN research. This means
that NICT has three functions: a funding func-
Figure 1. Network evolution.
tion like NSF, operation of the network
testbed, and their own research by NICT
researchers.
The Council for Science & Technology Policy
(CSTP), which belongs to the Japanese Prime
Minister’s Cabinet Office, has a mission to evaluate the importance of R&D projects proposed
by all ministries from the national point of view,
and in 2008 CSTP selected six R&D items with
the highest priority of 92 R&D proposals in the
all the areas of science and technology; one of
them is the R&D on NWGN technologies, which
means that NWGN R&D is one of the most
important national projects.
Figure 4 shows the requirements for NWGN
that the AKARI Project pointed out. Each item
is rather vague at this point in time, and it should
be made clear quantitatively from now on. It is
noted that the important requirements are especially:
• How to cope with complexity (versatile
appliances and heterogeneous networking)
(Internet)
(NGN)
• No overall network planning
• TCP/IP protocol is the only common rule
• Best effort based network; no clear responsibility and control
rules exist among networks
• User can have freedom to install applications
Terminal
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Legacy telephone network
RESEARCH ON NWGN IN JAPAN
Terminal
A
Server
IP router
network
(best effort)
IP router
IP router
network
network
(best effort)
(best effort)
IP router
IP router
network
network
(best effort)
(best effort)
Best effort bearer function to interconnect
a multiple-router-based network
• IP-based network with network control function and clear
responsibility for control
• QoS control and security functions are installed
• Maintain the Internet connection function
Terminal
NGN
(versatile
bearer
functions)
Terminal
NGN
(versatile
bearer
functions)
Server
NGN
(versatile
bearer
functions)
NGN
(versatile
bearer
functions)
QoS controlled bearer function to interconnect
multiple networks with clear responsibility
Figure 2. A comparison between the Internet and NGN.
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• Low energy consumption for a low carbon
society
• Compromise between openness and transparency vs. high security
Taking account of those requirements, the
AKARI Project is publishing “AKARI Architecture Conceptual Design” v. 1.2 in 2009.
TECHNOLOGICAL ISSUES TO BE
STUDIED
As shown in Fig. 3, clean-slate design for network architecture needs three study approaches.
Allocation of various networking functions heavily relies on the fundamental design concept.
The end-to-end concept in the Internet determines the allocation of networking functions to
routers and end hosts. The concept means that a
network should be as stupid as possible and an
end host should be intelligent, but the current
Internet cannot keep this concept, as shown in
Fig. 5. In addition, it is difficult to support strong
security functions under the end-to-end concept,
so the AKARI Project is now working on a concept for the allocation of networking functions
to meet the requirements. The AKARI Project
Design
principle
Bottom-up
Technical breakthrough
What can be realized by this breakthrough?
Figure 3. Research approach for a clean-slate designed architecture.
Social requirements
Design requirements
Pb/s backbone, 10 Gb/s FTTH, e-science
100 billion devices, M2M, 1-Mega stations
Competitive industry and user-oriented services
Medical care, traffic control, emergency,four-nine
Privacy, financing, food tracking, anti-disaster
Rich society, handicapped, aged support
Earth and human monitoring
Broadcasting and communication, Web 2.0
Economic incentive (business-cost model)
Ecology, sustainable society
Human possibility, universal communication
Capacity
Quantity
Openness
Robustness
Safety and security
Diversity (long-tail)
Ubiquity (pervasive)
Converge and simplify
Network model
Energy-saving
Evolvability
New generation network
Designed by the architecture
Figure 4. New generation social and design requirements in the 2020s
(source: National Institute of Information and Communications Technology).
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is also examining all the networking elements
shown in Fig. 6, taking into account the three
approaches in Fig. 3. Although the conclusions
of the examination have not yet been reached,
the important considerations are introduced
below.
END HOST
In the Internet an end host is a computer such
as a PC, server, or cellular phone, but appliances
ranging from a very tiny chip of radio frequency
identification (RFID) or a sensor that sends only
100-bit-level data, to a large-scale tailed display
that handles 100 Mpixels/system should be connected to the NWGN. The functions of end
hosts may vary widely, and we have to identify
the end host functions for the NWGN architecture.
LAYERING
The role of a network layer is to help recognition of the behavior of protocols, and build network systems and software on a layer-by-layer
basis. The layer structures of the Internet and
NGN are quite different from each other due to
the different concepts. Some ideas of protocols
without layer structure have been proposed. The
AKARI Project is now discussing a layering
structure for NWGN taking account of all the
network elements shown in Fig. 6.
DATA FORMAT TRANSPORTED
Top-down
Social requirements and long tail applications
Ideas to meet those requirements
New generation network architecture
A
The Internet and NGN use an IP packet format,
and NWGN may also apply a packet format for
data, but there can be many other approaches to
be applied. We have to examine merits and
demerits for other formats such as flow and circuit/path. Video streaming content may be transferred by flow or circuit/path better than by
packet structure from the QoS or low delay performance point of views. The AKARI Project is
studying the possibility of combining such data
formats, and an experimental photonic path/
packet combination switching system is being
built in NICT.
SEPARATION OF IDENTIFIER AND LOCATOR
The current IP address contains two different
functions, identification and location in a network. In the ITU-T standardization of NGN, the
separation of these functions is being discussed.
NWGN may apply separation of the identifier
and locator, and the AKARI Project is studying
a separate structure.
NETWORK VIRTUALIZATION AND
OVERLAY NETWORK
A history of the technological advancement of a
computer can be seen from the viewpoint of virtualizing a computer element. A computer user
can utilize a machine without any knowledge of
the precise physical structure of his/her computer. But in the 1960s, a computer user needed to
know the real memory address to make a program compute using the memory. Since then the
memory address has been virtualized; then all
the elements of a computer were virtualized, and
a user can write a program without any knowledge of the real physical structure of memory,
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» Cannot add new functions
» Cannot provide services for future society
• Entrust network with your life and living?
(tele-medicine, ITS and anticrime, finance)
• Rich life? (connecting sensor, RFID)
• Safe? Secure? (spam, DDoS)
• Never broken? how long? (sustainable society)
• Flexible to future change? (nobody knows future)
Universal communication?
Small devices?
Authentication?
Dependability?
Guaranteed
service?
Increasing layers
Adding functions
Anycast
M
ic
u lt
Loc
al a
ddr
essi
ng
as t
latfor
L3.5:I
IPsec
NAT
GMPLS
M
L4.5:P
Flowlabel
chal
Hierar sing
s
e
r
d
ad
P LS
F
rlay
:Ove
LX.5
dle
:Bun
LX.4
m
L4: Transport layer
Psec
L3.5:Mobile IP
Com
rout plicate
d
ing
L3: Internet layer
S
:MPL
L2.5
Mobility
L2: Data link layer
Original Internet
architecture
Individual optimum but NOT global optimum
The time to design from scratch has come!
Figure 5. The Internet: too complicated.
NETWORK TESTBED
Since NWGN is not an improvement of existing
IP networks, many ideas to realize a clean-slate
designed network, and experiments to verify
such new ideas and protocols are very important.
In the case of the Internet, the contributions of
Overlay network
(IP+ α) network/post-IP network
Underlay network
Photonic NW
Mobile NW
Sensor NW
Figure 6. Study items for NWGN architecture.
ARPANET and NSFNET, on which any
researchers were able to test their ideas, were so
great that those network testbeds evolved into
the commercial Internet. In case of NWGN, the
importance of its testbed is the same. NSF is
promoting the GENI testbed, and NICT is now
operating JGN2plus, which will be revised to be
capable of experiments to verify the NWGN
architecture, protocols, performance, security,
and applications. A large-scale NWGN testbed is
planned to start in 2011. NICT is considering a
connection with another clean-slate designed
network testbed such as GENI, and global con-
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All the elements should be redesigned.
NETWORK SCIENCE
One of the most difficult items to be solved in
NWGN is how to simplify very complex and
dynamic network functions, and control the
whole network in a stable and safe manner.
Cconventional network theory is not enough to
cope with these requirements, and new network
science should be studied. Recently new network
theory such as scale-free and bio-inspired networks have received attention. NWGN may need
autonomous functions and self-organization
capability to handle complex and heterogeneous
networking. These new theories or algorithms
should be verified as to whether they can contribute to handling NWGN.
Application
Cross-layer control mechanism
processor, interfaces, and input/output devices.
Why not virtualize a whole network so that we
can utilize the network for our own purposes
without any knowledge of its physical structure
as we do when using a computer? In order to
realize network virtualization, each element of a
network should be virtualized. Research activities on a virtual router and server can be
observed globally, and the AKARI Project is
also concentrating its study resources on this
research item. An experimental testbed of an
overlay network with the virtualization concept,
Planet Lab [8], is operating. Figure 7 illustrates a
conceptual diagram of a network virtualization
architecture.
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Research on NWGN
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(a)
and Future Internet,
which are aiming at
Overlay network
VN1
building a new
VN1
paradigm beyond
the Internet, and the
Real testbed network
success of this
attempt relies on
(b)
good competition
Self-evolvable
and tight
VN1
VN1
collaboration among
research community
Real operational network
in US, Europe,
and Asia.
Physical network
(c)
VN1
Optical path network
Wireless network
VN1
Real operational network
Figure 7. AKARI architecture for network virtualization (concept): a) isolated virtual networks; b) transitive virtual networks; c) overlaid virtual networks.
nections between future network testbeds are
eagerly expected.
LONG TAIL APPLICATIONS
As shown in Fig. 8, innovations in network technologies have been derived from so-called long
tail applications. The Internet and Web were
not originally applications for the general public, but for a small number of researchers and
scientists. The top-down approach in Fig. 3
should take up advanced applications that need
very high-level performance or functions even
though the number of users is quite small. In
case of NWGN, examples of long tail applications are grid computing, large-scale tailed display, advanced digital entertainment such as
digital cinema, other digital stuff (ODS), networked games, and so on. The OptIPuter [9]
project is developing a 100 Mpixel display system with 30 × 10 GE interfaces (total 1/3 Tb/s)
and a 60 Tbyte disk.
As for digital cinema, the Digital Cinema
Initiative (DCI) [10] made the digital cinema
specification with 4K (4096 × 2160 pixels/frame)
definition according to Digital Cinema Consortium of Japan (DCCJ) [11] contributions; based
on this specification, Warner Brothers, Toho
Cinema Co, and NTT Group performed the
world’s first joint trial for 4K digital cinema distribution from a Hollywood studio to digital
screens in Tokyo and Osaka over broadband IP
networks across the Pacific Ocean. This trial
was called 4K Pure Cinema Trial [12]; very
popular movies such as “Harry Potter” and
“The Da Vinci Code” were digitalized with 4K
resolution, and the digital cinema contents were
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compressed by JPEG2000, encrypted for security in a Hollywood studio, and then transmitted
over to NTT network operation centers in
Tokyo and Osaka. Then the contents were distributed to movie theaters there, unencrypted,
decoded, and projected on the screen by SONY
SXRD 4K cinema projectors. A two-hour movie
with 4K DCI specification has 6 Tbytes; streaming of 4K non-compressed digital cinema content needs 6 Gb/s speed, and compressed
cinema with JPEG2000 needs 300 Mb/s. The
4K Pure Cinema Trial has successfully finished,
and an actual business in digital cinema distribution over broadband IP networks has recently been announced. Content (high definition
video of musicals, operas, Kabuki, etc.) will be
distributed to a large-scale flat TV display in a
home theater. These high-level applications will
have a great impact on the performance of
NWGN.
INTERNATIONAL COLLABORATION
AND STANDARDIZATION
Research on future networks beyond IP has
begun in the United States, the European Union,
Japan, and Korea. Research and development
inherently involves competition as well as collaboration. It is noted, however, that collaboration
is more important in this case because the period of R&D may be very long, possibly more
than 10 or 20 years, and research items are quite
broad and difficult to solve, so no single organization or even country can afford to study all the
technologies required. International symposia
and workshops concentrating on topics beyond
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CONCLUSION
This article overviewed research activities on
beyond the Internet and NGN especially in
Japan. We can remember that the US government continued to support ARPANET and
NSFNET for more than 20 years, and from those
network research platforms, excellent new ventures such as CISCO, Yahoo, Google, Amazon,
etc. were born, and the new Internet industry
has grown up. Research on NWGN and Future
Internet, which are aiming at building a new
paradigm beyond the Internet, and the success
of this attempt relies on good competition and
tight collaboration among research community
in the United States, Europe, and Asia.
ACKNOWLEDGMENT
I would like to express my gratitude to ITU-T,
especially Dr. Yoichi Maeda, Chairman of the
ITU-T Kaleidoscope Academic Conference and
Chairman of ITU-T Study Group XV, and Professor Toru Asami of the University of Tokyo
for giving me an opportunity to introduce the
topic of R&D on beyond the Internet and NGN
at the conference. I also appreciate Dr. Nim K.
Cheung who solicited an article for IEEE Communications Magazine. The submission of this
article is supported by many researchers in the
AKARI Project, especially the late Dr. Masaki
Consumer users
IP should be held, and conventional conferences
shoud be utilized as well. Some new workshops
and symposia have been held or are being
planned this year.
ITU-T held a new conference, the ITU-T
Kaleidoscope Academic Conference, in Geneva,
Switzerland last May with IEEE Communications Society co-sponsorship. I was invited to
talk about the new generation network, and this
talk made some impact on the discussions about
future network standardization in ITU-T.
ITU-T Study Group XIII has just established
a Focus Group to investigate the status of R&D
beyond the Internet and NGN in the world. This
policy of ITU-T and IEEE Communications
Society to host such an international conference
to discuss future network technologies before
the standardization process with the academic
community seems excellent, and collaboration
among network researchers’ communities in
academia and the standardization community
can be well performed. This new event will
impact on a standardization process.
NICT participated in the U.S.-Japan Joint
Workshop on New Generation Network and
Future Internet held in Palo Alto, California,
last October, and also the EU-Japan Symposium
on New Generation Network/Future Internet
held in Brussels, Belgium, last June. These
opportunities contributed to exchanging information on the R&D status in each region and
more detailed research collaboration among
research groups in both areas.
The next important collaboration is to interconnect the network tesbeds to verify new ideas
and technologies for beyond IP over large-scale
global models.
Number of users
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Innovations have been derived from
Long tail applications.
e.g. Internet, Web
Long tail application
Enterprise users
100 Mb/s
Researchers and scientists
100 Gb/s
Transfer rate
Figure 8. Long tail application in the future, 4K digital cinema, and ODS.
Hirabaru in NICT who was the leader of the
AKARI project. This article is dedicated to him.
REFERENCES
[1] Proc. 1st ITU-T Kaleidoscope Academic Conf. “Innovations in NGN,” Geneva, Switzerland, May 12–13, 2008.
[2] A. Arima, “Deployment of NTT Group’s Next-Generation
Network;” http://www.soumu.go.jp/s-news/2007/pdf/
Deployment_of_NTT_NGN_eng.pdf
__________________
[3] Global Environment for Network Innovations; http://
___
www.geni.net/
[4] NSF NeTS FIND Initiative; http://www.nets-find.net/
[5] Seventh Framework Program; http://cordis.europa.eu/
fp7/
__
[6] NWGN Forum; http://forum.nwgn.jp/gaiyo.html (in
Japanese)
[7] AKARI Architecture Conceptual Design; _______
http://akariproject.nict.go.jp/eng/conceptdesign.htm
_____________________
[8] PlanetLab; http://www.planet-lab.org/
[9] OptIPuter; http://www.optiputer.net/
[10] Digital Cinema Initiatives; http://www.dcimovies.com/
[11] Digital Cinema Consortium of Japan; http://www12.
ocn.ne.jp/~d-cinema/index2.html
_________________ (in Japanese)
[12] NTT Group; http://www.ntt.co.jp/news/news05e/
__________
0510/051011.html
ADDITIONAL READING
[1] JGN2plus; http://www.jgn.nict.go.jp/english/index.html
BIOGRAPHY
TOMONORI AOYAMA [F] (aoyama@dmc.keio.ac.jp)
_____________ received his
B.E., M.E. and Dr.Eng. from the University of Tokyo, Japan,
in 1967, 1969, and 1991, respectively. Since he joined NTT
Public Corporation in 1969, he has been engaged in
research and development on communication networks
and systems in the NTT Electrical Communication Laboratories. From 1973 to 1974 he was at MIT as a visiting scientist. In 1994 he was appointed director of the NTT
Opto-Electronics Laboratories, and in 1995 he became
director of the NTT Optical Network Systems Laboratories.
In 1997 he left NTT and joined the University of Tokyo. In
April 2006 he moved to Keio University, and is currently a
professor at the Research Institute for Digital Media and
Content, Keio University. He is a member of the Science
Council of Japan and an IEICE Fellow. He is currently serving as President-Elect of IEICE. He serves as Chair of the
Photonic Internet Forum in Japan, the Digital Cinema Consortium of Japan, and Vice-Chair of the Ubiquitous Networking Forum and New Generation Network Promotion
Forum.
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ITU-T KALEIDOSCOPE
Open Standards: A Call for Change
Ken Krechmer, University of Colorado
ABSTRACT
Digital communication is both pervasive and
vital across society. This creates a growing public
interest in the technical standards that proscribe
public communications. The public is demanding
open standards. The rallying cry “Open Standards” means different things to different
groups. This article reviews the different needs
of specific groups of society and develops ten
different requirements for open standards. To
implement these requirements, changes to the
rules and procedures of standardization organizations, international bodies (e.g., WIPO, WTO),
and national patent office rules are proposed.
Interestingly, technical changes, in the form of
new standardized protocols, rather than legal or
policy changes, appear to be the most important
changes to meet the requirements of open standards.
“Standards function as feathers that guide the
arrow of technology. While feathers are light and
seemingly trivial on an arrow’s shaft, without feathers, few arrows find their mark. Without standards,
few technologies find their market” [2].
INTRODUCTION
This paper is the revised
version of the author’s
presentation at the First
ITU-T Kaleidoscope Academic Conference [1].
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Standardization — the creation, implementation,
and use of technical standards — offers a powerful means for technology to respond to public
needs. Technical standards that are more responsive to public needs are often termed open standards. But what does open standards mean?
Multiple sources of implementations? No intellectual property costs? Standardized in a formal
standardization committee? The standard is the
same worldwide? Backward compatibility is
maintained? The standard is maintained as long
as it is used? Open standards mean different
things to different people.
Understanding what an open standard is
depends on the vantage point of the viewer and
the type of technology being standardized. Public standards development organizations (SDOs),
private standardization organizations (consortia),
different legal communities, economists, software developers, original equipment manufacturers, end users, and governments have quite
different views of open standards and how to
achieve them.
A technical standard is an established reference, that is, a codified (a model or written rep-
0163-6804/09/$25.00 © 2009 IEEE
resentation) and quantified (measurable) reference, established by an authority, committee, or
market. This article develops the requirements
that bear on the openness of a standard and proposes policy and procedural changes to both
related national and international organizations.
Openness is a direction, not a destination. We
must understand where we are heading before
we claim to have arrived.
THE EMERGENCE OF IMPLEMENTERS
As SDOs developed in the late nineteenth century, they focused — often with government
approval — on supporting the open creation of
standards and not on the open implementation
or open use of standards. As examples, the
railroads, utilities, and car manufacturers dominated the SDOs and were the major creators
and also the implementers and users of standards. The standards creators had no need to
consider the needs of implementers and users
separately — they were the implementers and
users. In the nineteenth and early twentieth
centuries, the significant standardization policy
issue was the conversion from independent
company specifications to single SDO standards [3].
After the middle of the twentieth century,
large integrated organizations (companies that
bring together research and development, production, and distribution of their products or
services, e.g., IBM, AT&T, Digital Equipment
Corp., British Telecom, France Telecom, NTT)
focused on information and communications
technology (ICT) standardization. These organizations had engineers who functioned, often on
a full-time basis, as the standards creators for
the integrated organization. These standards creators supported specific SDOs that were
required for the broad aims of the integrated
organization [4].
In the later twentieth century, the growth of
personal computing, cellular telephony, and the
Internet caused the number of implementers
and users of standards to increase dramatically.
The stage was set for major changes in standardization activity and processes. By the middle of
the 1980s, a new industrial movement emerged
where larger integrated organizations refocused
into smaller profit-directed segments. Each segment of the overall organization focused only on
its own market(s) and therefore, only supported
the standardization organizations that appeared
necessary for its specific product development
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requirements [5]. This new industrial movement
marked the rise of implementer activity (as an
independent product development group) in
standardization and with it, the rise in consortia
standardization. In the same period, the overarching integrated standardization organization
was disbanded in most cases (e.g., AT&T, IBM,
US PT&T’s BellCore).
Since the 1980s, the technical communications standardization processes have been in
transition from being driven by standards creators (standardization participants who are
motivated to develop new standards) to being
driven by standards implementers (standardization participants who are motivated to produce new products that embody one or more
standards). In addition, the users (who usually
do not participate in the ICT standardization
process) have a growing interest in seeing the
concept of openness address their requirements. This view was confirmed in the 1994
report sponsored by the U.S. National Science
Foundation, which described an open data
network as being open “to users, to service
providers, to network providers and to change”
[6]. This report identifies the three major perspectives on open standards: creators, implementers, and users.
Product development groups in segmented
organizations have no history or allegiance to a
specific SDO and choose to support any standardization organization that best fits their product development and marketing requirements.
Often such a fit is made by sponsoring a new
consortium to address the standardization
requirements of a developer’s product implementation. However, what product implementers
considers an open standard may be quite different from what a standards creator considers an
open standard. And it also is different from what
a user might consider an open standard.
How many of the indications of an open
standard in Table 1 are required for a standard
to be considered open? Some say standards are
open when they do not include controlled intellectual property (e.g., European Union [EU],
World Wide Web Consortium). Of course, this
may be unfair to those who have worked to create useful intellectual property. Some say standards are open when they are developed in a
recognized standardization committee (e.g., formal standardization organizations such as the
International Standards Organization [ISO] or
the International Telecommunication Union
[ITU]). However, it is now recognized that the
difference between formal standardization organizations and consortia is often slight [7]. It
appears there is considerable confusion about
what an open standard is, as well as how to
achieve it.
The search for open standards indicates the
need of people to influence the standards that
affect them. Because microprocessor-based technology changes rapidly, open standards are
required to respond to such change and yet support public control of new technology. Reviewing the history of standardization shows how
standards were used to control technology for
the public good and offers insights into how
open standards can be achieved today.
Rights/area of interest
Creator
Implementer
User
1
Open meeting
X
2
Consensus
X
3
Due process
X
4
Open IPR
X
X
X
5
One world
X
X
X
6
Open change
X
X
X
7
Open documents
X
X
8
Open interface
X
X
9
Open access
X
X
10
Ongoing support
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X
Table 1. Different views of open standards.
THE SUCCESSIONS OF STANDARDS
Over the course of history, different standards
supported each wave of civilization (e.g., agrarian, industrial, information) [2]. The range of
standards required to support a new wave of civilization and the associated technologies is
termed a succession of standards. Each succession of standards utilizes different means to balance public and private interests. The succession
of standards required to support the industrial
age are those standards that define the similarity
of objects or processes; these are similarity standards. During the industrial revolution, the
importance of creating public similarity standards was understood [8]. The use of patents
emerged during the same period as a means to
offer value to the entrepreneur. Similarity standards created in standardization organizations
that supported consensus and due process, when
coupled with patents, offered a successful balance of the public and private interests.
In the information age, the standards that
define interfaces emerged as the compatibility
standards succession. A fair balance of public
and private interests has yet to be achieved here.
Compatibility standards began with the development of private interfaces. Such private interfaces were controlled by patents or proprietary
information. Patents on interfaces have a winner-take-all effect, assuring a very large private
gain to the innovator who controls a high volume interface. Many have recognized the need
for open standards for high volume interfaces.
But creating open standards for such interfaces
is more difficult than creating open similarity
standards.
The open creation, open implementation, and
open use of compatibility standards is required
to create public interfaces. To achieve a better
balance of the public value of an open standard
with the private gain possible from interfaces
defined by compatibility standards, changes are
required.
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The market is the
best means to
determine if a performance enhancement, controlled by
IPR, of an interface
provides sufficient
value, given its cost.
Market determination — a basic
means to support
open interfaces —
can only function if
the controlled technology is optional in
any compatibility
standard.
A better balance of public and private interests on compatibility standards requires recognition that similarity and compatibility standards
have very different impacts on society. Organizations that deal with both successions of standards must have different approaches and
policies to address similarity and compatibility
standards. A fundamental issue is that compatibility standards define interfaces. Communications interfaces created in standardization
committees are mutual agreements, not inventions; therefore, the intellectual property claims
on the implementations of compatibility standards that define interfaces should be minimized.
In the post-information age, a new succession
of standards emerged. When interfaces are computer controlled, they can adapt to different
requirements. The standards that define how to
identify, negotiate, and select among different
interface requirements are termed adaptability
standards. Developing and using adaptability
standards offers new means to achieve a successful balance of public and private interests for
compatibility standards.
Where algorithms controlled by intellectual
property rights (IPR) are desired to optimize the
performance of interfaces, such algorithms could
be optional, thereby rendering the interface
more open. Adaptability mechanisms allow the
selection of such options. Standardization organizations should standardize controlled interfaces only where it is clear that the public good
— increased performance of the interface using
controlled technology — is greater than the private gain desired by the owners of the controlled
technology. The market is the best means to
determine if a performance enhancement, controlled by IPR, of an interface provides sufficient
value, given its cost. Market determination — a
basic means to support open interfaces — can
only function if the controlled technology is
optional in any compatibility standard.
THE TEN REQUIREMENTS OF
OPEN STANDARDS
The ten requirements described in Table 1 are
fundamental to the broadest concept of open
standards. Placing each requirement in context
helps explain the requirements and identify
where different policies and procedures to support each requirement are required:
1 Openness: All stakeholders may participate
in the standardization process.
2 Consensus: All interests are discussed and
agreement found with no domination.
3 Due process: Balloting and an appeals process may be used to find resolution.
These three requirements of open standards
are related to the creation of standards. In the
early twentieth century, these requirements
emerged to prevent exploitation of the standardization process by dominant organizations or factions. This was very important during the period
when there was often a dominant railroad, car
company, telephone company, and so on in each
major country of the world. As trade expanded,
the market dominance of such companies has
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declined, helped in part by active anti-trust concerns. The participants of standardization meetings also are more aware of these issues now and
better able to counter attempts by one faction to
dominate a standardization process.
4 One world: The same standard for the same
function, worldwide.
The first four requirements of open standards
are at the heart of the World Trade Organization (WTO) Agreement on Technical Barriers to
Trade, Code of Good Practice. The fourth
requirement, the same standard for the same
function worldwide, is an important requirement
to prevent technical barriers to trade (TBT).
Yet, many interface standardization committees
create standards for a specific geographic area
(e.g., the Alliance for Telecommunications
Industry Solutions [ATIS] in the United States,
the European Telecommunications Standards
Institute [ETSI] in Europe, the Telecommunication Technology Committee [TTC] in Japan).
The creation of compatibility standards by country or region does not make worldwide communications easier. One way to address this
dichotomy of national and regional standardization organizations and the need for communications worldwide is to utilize adaptability
standards to negotiate among multimode devices
supporting multiple national or regional compatibility standards.
Common worldwide adaptability standards
must be developed in international standardization organizations and should be required wherever two or more compatibility standards
compete to define the same microprocessor-controlled interface.
5 Open IPR: Low or no charge for IPR
required to implement the basic standard.
IPR is allowed for options and proprietary
extensions.
The existing procedures for addressing IPR
issues in standardization organizations were created to deal with IPR relating to similarity standards; they do not work well for IPR relating to
compatibility or adaptability standards. The IPR
relating to similarity standards and the IPR
relating to compatibility standards have very different economic impacts. The existing reasonable and non-discriminatory (RAND) rules of
standardization organizations for IPR are appropriate for rights on similarity standards yet are
often ineffectual for IPR relating to compatibility standards. It seems likely that IPR should not
be allowed on adaptability standards.
As an example, a cell phone implementer
invents and patents a new battery that provides
more use per charge. The IPR relates to the
chemistry of each battery, which need not be
standardized. Each user can decide if the additional cost for longer battery life is warranted
relative to its cost. Properly written similarity
standards offer both the implementer and the
user flexibility in their choice of new technology.
The case with compatibility standards that
define interfaces is quite different. If the cell
phone implementer holds IPR on the compatibility standard that defines the air interface of
the cell phone system, all who wish to use that
cell phone system must pay for that IPR without
any decision on their part about the value of that
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IPR to them. Using patents to control compatibility is effectively an expansion in the applicability of the patent system that greatly impacts the
rights of others. This unplanned expansion of
the patent system must be recognized and
addressed.
Standardization committees should require
an adaptability mechanism whenever multimode
operation to support proprietary interface features is desired. When proprietary features
included in an interface standard are optional,
the implementers of the equipment on each side
of the interface standard (e.g., cell phone and
cellular base station) must choose if an option is
worth including in their implementations. This
gives the implementers a practical negotiating
position for specific IPR. Conversely, if a controlled option significantly improves the performance of the system, implementers that do not
choose to include that option in their implementations run the risk of not being competitive with
implementers that do include the option. In this
manner, a market-based negotiation between
implementers and IPR holders is supported by
requiring proprietary features controlled by IPR
in compatibility standards to be optional and
negotiable.
Far too often each participant in the standardization process accepts the IPR of others
into a new interface standard if its IPR also is
accepted into the standard. This serves to balance intellectual property benefits among the
standardization participants. Although this balance allows consensus to be achieved, it is not
fair to those who have not participated in the
standardization process. It is also unfair to users
who will ultimately bear the cost of the IPR,
often without any input in determining if the
IPR included in a standard are desirable to
them. It is the high-tech equivalent of taxation
without representation.
National courts, governments, and many
international organizations do not appear to be
fully aware of the impact of a compatibility standardization process. The conversion of public
telephone utility companies (PTTs) to private
companies offers one example. When a PTT
submitted controlled technology to standardization committees for inclusion in an interface
standard, it was usually with the assumption
(sometimes stated) that no royalties would be
charged because it was a public utility. Where
patented technology of the PTT is already
included in public compatibility standards, the
future value of that patented technology is
assured. When a PTT patent portfolio was transferred to a private company, the private company received a windfall (increased private gain
from the future patent royalties). In effect, it is a
transfer of value previously in the public domain
to private enterprise. In 1996, a significant portion of the AT&T Bell Labs patent portfolio was
transferred to its private successor, Lucent. After
this transfer, Lucent began charging for patents
that previously had not been enforced. The open
use of AT&T’s patents included in existing public compatibility standards was an issue that
should have been considered in the transfer of
these patent rights from AT&T, formerly a public utility, to Lucent, a private company.
Many of these problems can be minimized by
a policy change in the standardization organizations. All controlled IPR should be optional in
compatibility standards and disallowed in adaptability standards. When a controlled IPR
emerges after the standard is issued, the standard should be changed to make such an IPR
optional. When compatibility standards can be
upgraded automatically — for example, over the
Internet — making such changes in the standard
after it is issued is practical.
6 Open documents: All may access and use
committee documents, drafts, and completed standards for their intended purpose.
Committee documents, completed standards,
and software documentation should be readily
available. In practice, the openness of a standardization meeting is closely related to the
availability of the documents from the meeting.
The Internet Society (ISOC) supports an internal standards-making organization, the Internet
Engineering Task Force (IETF). The IETF has
pioneered new standards development and distribution procedures based on the Internet.
Using the Internet, the IETF makes available its
standards, termed request for comments (RFCs),
and the drafts of such standards on the Web at
no charge. Using the facilities of the Internet,
IETF committee discussion and individual technical proposals related to the development of
standards can be monitored by anyone and a
response offered. This transparent development
of IETF standards has been sufficiently successful that many other standardization organizations are now doing something similar.
Ultimately, as the use of technology expands,
everyone has an interest in technology and the
technical documents that describe it. Using the
Internet, access to documents and discussion
may be opened to all. In this way, informed
choices can be made about being involved in a
specific committee or project, and potential new
participants could evaluate their desires to participate. Open documents deserves to be a
requirement for any standardization organization that wishes to be considered open.
7 Open change: All changes are proposed and
agreed in the standardization organization.
To maintain openness, all changes to existing
standards must be presented and agreed in a
standardization organization supporting the previous six requirements of open standards (identified above). Controlling changes is a powerful
tool to control interfaces when system updates
can be made in real time and stored in computer
memory. As an example, even with the most liberal of IPR policies, Microsoft could still control
its Windows application programming interfaces
(APIs) by distributing updates (changes) to users
that update both sides of each API at the same
time. Competing vendors’ products on one side
of the same API, without a similar update at the
same time, would be rendered incompatible by
such a Microsoft online update.
The only way that interfaces can remain open
is when all changes are presented, evaluated,
and approved with a common distribution plan
in a standardization committee that supports the
first six requirements identified above. Considering how computers can be connected over the
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National courts,
governments, and
many international
organizations do not
appear to be fully
aware of the impact
of a compatibility
standardization process. The conversion
of public telephone
utility companies
(PTTs) to private
companies offers
one example.
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One of the earliest
etiquettes is ITU Recommendation T.30,
which is used in all
Group 3 facsimile
machines. Part of its
function includes
mechanisms to interoperate with previous Group 2
facsimile machines
while allowing new
features to be added
to the system without losing backward
compatibility.
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Internet, identifying and requiring mutually
agreed changes is vital to the concept of open
standards.
This concept is not widely understood. The
original U.S. judicial order to break up the
Microsoft operating system and application software monopoly did not address this key issue
[9]. On March 24, 2004, the European Commission (EC) announced its decision to require
Microsoft to provide their browser (Explorer)
independently of the Windows operating system
and make the related Windows APIs available to
others [10]. More recent EU actions on the
Microsoft server interfaces have similar issues.
Unfortunately these decisions do not address
the requirement for mutually agreed changes to
maintain “accurate interoperability information.”
It appears that neither the U.S. judiciary nor the
EC understands that a computer-controlled
interface cannot be mandated to be an open
standard. For such a standard to be open, it
must be created and maintained in an open standardization process. As currently conceived, the
EU approach to opening Microsoft server interfaces is likely to fail.
8 Open interfaces: Support migration (backward compatibility) and allow proprietary
advantage, but standardized interfaces are
not hidden or controlled.
The economic interests of the user are best
served when manufacturers or service providers
compete. Without competition, a seller becomes
dominant and the user’s interests, economic and
otherwise, often are not addressed. Standards
represent a means to help balance the buyers’
and sellers’ interests, but when everything about
a transaction is standardized, there is no longer
any product competition, only price competition.
Although price competition is desirable, the
manufacturer or service provider also must have
the possibility of feature competition to motivate
innovation. In similarity standards, a balance can
be achieved by standardizing some aspects of a
product or service but allowing others to be proprietary. For example, the size of a brick can be
standardized, but color, texture, or strength can
be proprietary features. Compatibility (interface)
standards also require a balance to support innovation. Unfortunately, many people think that all
interfaces of a specific type must be the same to
ensure compatibility. This is not correct. Interfaces can be made adaptable to support proprietary advantage (private gain), as well as
compatible operation (public good).
Interfaces that are not hidden or controlled
and that support migration, also can support
proprietary advantage. Such interfaces, which
exhibit both proprietary and public advantages,
are an emerging approach to interface standards
used between programmable systems. Programmable systems with changeable memory
make possible multimode interfaces that can be
changed to support backward and forward compatibility, as well as compatibility to other modes
of operation. The idea that open interfaces
should embody both public and private advantage is relatively new. But interest is increasing
due to the considerable success of open interfaces in facsimile, telephone modems, and digital
subscriber line transceivers.
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One way of achieving open interfaces is to
implement a newer technique called an etiquette
[11]. Etiquettes provide:
• A means to negotiate between two or more
devices in different spatial locations to
determine compatible protocols and
options.
• A means to allow both proprietary and public enhancements to the interface that do
not impact backward or forward compatibility.
• Adaptability, so that one communications
system can become compatible with a different communications system (e.g., by
uploading the required software).
• Easier system troubleshooting by identifying
specific incompatibilities.
As long as the etiquette itself is common
between the equipment at both ends, it is possible to receive the code identifying each protocol
or option supported by the equipment at a
remote site. Checking this code against a data
base of such codes on the Web or in a manual,
the user can automatically or manually select
compatible operation or determine what change
is required in their system or the remote system
to enable compatibility.
One of the earliest etiquettes is ITU Recommendation T.30, which is used in all Group 3
facsimile machines. Part of its function includes
mechanisms to interoperate with previous Group
2 facsimile machines while allowing new features
(public, as well as proprietary) to be added to
the system without losing backward compatibility. Another etiquette is the ITU standard V.8,
which is used to select among the V.34 and higher modem modulations. More recently, ITU
G.994.1 provides a similar function in digital
subscriber line (DSL) equipment.
As an example of the usefulness of open
interfaces, consider Microsoft APIs. Assume that
an open standard based on a Microsoft Windows
API is created. Then, any vendor could create
an operating system (OS) to work with Microsoft
applications or create applications to work with
the Microsoft OS that utilize that API. If any
vendor (including Microsoft) identified a new
function, such as a music delivery service or
Internet Protocol (IP) TV, which was not supported across the standardized API, that vendor
could then offer the new function, as an identified proprietary feature across the API, to users
who have purchased that vendor’s OS and appropriate applications, while not impacting compatibility for those who have not. Because an open
interface supports proprietary extensions, each
vendor controls the way the new function is
accessed across the API but does not change the
basic compatibility of the API. In this manner,
implementers — including Microsoft — are able
to maintain control and add value, based on the
desirability of the new functions they offer.
An open interface offers a means to address
current political concerns:
• The concern of the French government that
only Apple iPods can download music from
Apple iTunes Web sites.
• The push of the Chinese government for
their own communications technology in
Chinese communications systems [12].
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Phase
Activity
Description
Major interest group
1
Create standard
The major task of SDOs
Creators
2
Fixes (changes)
Rectify problems identified in initial implementations
Implementers
3
Maintenance (changes)
Add new features and keep the standard up to date with
related standards work
Users
4
Availability (no changes)
Continue to publish, without continuing maintenance
Users
5
Rescission
Removal of the published standard from distribution
Users
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Table 2. Standards life cycle.
• The EU and previous U.S. anti-trust actions
against the Microsoft proprietary software
interfaces.
In each of these cases, open interfaces that
support adaptable operation could resolve the
political concerns without any direct government
involvement in standardization.
9 Open access — objective conformance
mechanisms for implementation testing and
user evaluation.
Implementation assessment covers all possible parameters that might require identification
for conforming to accurate, safe, and/or proper
use. Such parameters could include physical
access (e.g., access by people with disabilities),
safety (e.g., having a CE or UL mark — the
European and U.S. indications that equipment
is designed safely), and correct weights and
measures (e.g., certification of scales and gasoline pumps), as well as interface compatibility
indicated by noting a term that indicates the
type of interface (e.g., V.92, WiFi, Bluetooth,
global system for mobile communications
[GSM]).
For products that have standardized interfaces, such as communications equipment or
communications software, an interoperability
event might be required (often termed a plugfest) to test whether different implementations
interoperate.
The complexity of multilayer communications
products makes compatibility more difficult to
achieve, let alone identify. Adaptability mechanisms could help achieve the highest level of
compatibility. Such mechanisms could identify
incompatibility in a manner that would allow
upgrades (automatic or manual) to achieve compatibility. However, adaptability standards
require new levels of testing to verify their long
term ability to maintain backward compatibility.
Whereas all other implementations of standard
successions are tested to verify conformance to a
standard, implementations of adaptability standards also must be tested to verify that they
ignore what they do not recognize, that is, any
extensions to the standard that occur in the
future. This level of testing represents new criteria for conformance testing of implementations
supporting adaptability standards.
10 Ongoing support — standards are supported until user interest ceases.
Users desire their products, services, and the
related software to be supported until their need
ceases, rather than when implementer interest
declines. On-going support of hardware, software, and services, and their associated standards, is of specific interest to end users because
this support can increase the life of their capital
investment in equipment or software. The support of an existing standard, which directly
impacts any products that utilize the standard,
consists of five distinct phases (Table 2).
It is difficult to interest users in the first
phase of standards development [13]. Even the
second phase, fixes, may be of more interest to
the creators and implementers than the users.
The next three phases, however, are where users
have an interest in maintaining their investment.
Currently, few standardization organizations
actively address maintaining their standards
based on user desires. Greater user involvement
in the on-going support of standards could be
practical by taking advantage of the Internet to
notify users of potential changes in specific standards. Increasing user involvement with the
maintenance phases of the standardization process can also represent new economic opportunities for standardization organizations. For
example, for a small fee, users could register
their interest on the Internet in a standard or
group of standards; then, whenever a new support phase of those standards was being considered, the registered users would be notified and
could raise their concerns in a similar way as any
other meeting attendee. Over time, such opportunities also might increase user preferences for
standards from the standardization committees
that provide such policies.
POLICY AND PROCEDURE
RECOMMENDATIONS
Listed below, in order of importance, are the
changes proposed to the policies and procedures
of various organizations.
Changes to standardization organizations:
• Support open interfaces (adaptability standards) as a requirement, with all compatibility
standards
specifying
microprocessor-controlled interfaces with
changeable software.
• Allow IPR as an option only in compatibility standards. When IPR emerge after standardization, change such controlled
functions to options where practical.
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Standardization and
intellectual property
processes are always
evolving, and
because of this
flexibility, these
systems have worked
well in the past. This
evolution must continue to address the
broad changes as
standards evolve
from similarity to
compatibility to
adaptability.
• Standardization of adaptability standards is
to be addressed only in worldwide standardization organizations.
• Each standardization organization should
maintain and publish a list of how it
addresses each of the ten open standards
requirements.
• Offer users the means to participate in the
maintenance of SDO standards.
Changes to World Trade Organization policies:
• Define as barriers to trade the lack of open
change procedures and lack of open interfaces of microprocessor-based compatibility
standards.
Changes to European Commission competition and antitrust policy:
• When interfaces are required to support
competition, empower a standardization
organization to create and maintain them.
Changes to World Intellectual Property Organization (WIPO) policies:
• WIPO should evaluate the economic basis
of IPR claims on international interface
standards and make recommendations concerning when controlled technology should
be optional in interface standards.
Changes to the patent policies of individual
countries:
• Require greater demonstration of uniqueness
for patent claims that control interfaces.
• Shorter term on patent claims that can control interfaces (e.g., algorithms).
Standardization and intellectual property processes are always evolving, and because of this
flexibility, these systems have worked well in the
past. This evolution must continue to address the
broad changes as standards evolve from similarity
to compatibility to adaptability. This requires the
further evolution of the policies and procedures
of all the organizations that are involved.
REFERENCES
[1] K. Krechmer, “Open Standards: A Call for Action,” Proc.
1st ITU-T Kaleidoscope Academic Conf., Geneva,
Switzerland, May 12–13, 2008.
[2] K. Krechmer, “The Entrepreneur and Standards,” in
International Standardization as a Strategic Tool: Commended Papers from the IEC Centenary Challenge, IEC,
Geneva, Switzerland, 2006, pp. 143–54.
[3] R. A. Brady, “Industrial Standardization,” Ch. 1, Historical Setting for the Standardization Movement, Nat’l.
Industrial Conference Board Inc., 1929.
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[4] C. Cargill, Information Technology Standardization, Digital Press, 1989, p. 113–14.
[5] A. Updegrove, “Consortia and the Role of the Government in Standards Setting,” in Standards Policy for the
Information Infrastructure, B. Kahin and J. Abbate,
Eds., MIT Press, 1995.
[6] NRENAISSANCE Committee, Computer and Telecommunications Board, National Research Council, Realizing
the Information Future, Nat’l. Academy Press, 1994.
[7] T. M. Egyedi, “Consortium Problem Redefined: Negotiating ‘Democracy’ in the Actor Network on Standardization,” Int’l. J. IT Standards and Standardization
Research, vol. 1, no. 2, July–Dec., 2003.
[8] R. A. Brady, “Industrial Standardization,” Ch. 1, Historical Setting for the Standardization Movement, National
Industrial Conference Board Inc., 1929, p. 14.
[9] K. Krechmer and E. Baskin, “The Microsoft Anti-Trust
Litigation: The Case for Standards,” Soc. Eng. Stds.,
2000; http://www.ses-standards.org/displaycommon.
cfm?an=1&subarticlenbr=56
_______________
[10] European Union, “EU Commission Concludes Microsoft
Investigation, Imposes Conduct Remedies and a Fine,”
Delegation of the EC to the USA, no. 45/4, Mar. 24,
2004; http://www.eurunion.org/news/press/2004/
20040045.htm
_______
[11] K. Krechmer, “The Fundamental Nature of Standards:
Technical Perspective,” IEEE Commun. Mag., vol. 38,
no. 6, 2000, p. 70.
[12] P. Qu and C. Polley, “The New Standard-Bearer,” IEEE
Spectrum NA, vol. 42, no. 12, Dec. 2005, pp. 49–52;
http://www.spectrum.ieee.org/dec05/2361
[13] K. Naemura, “User Involvement in the Life Cycles of Information Technology and Telecommunications Standards,”
in Standards, Innovation, and Competitiveness, R. Hawkins,
R. Mansell, and J. Skea, Eds., Edward Elgar, 1995.
BIOGRAPHY
K EN K RECHMER [SM] (krechmer@csrstds.com)
_____________ started his
technical career in 1961 as a technician (after leaving MIT)
and quickly became a practicing engineer working for several electronics companies in the 1960s and 1970s. After
founding one electronics company and working in sales
and marketing for several others, he began consulting in
1980. As a consultant he participated in the development
of the International Telecommunications Union Recommendations for Group 3 facsimile (T.30), data modems (V.8,
V.8bis, V.32, V.32bis, V.34, V.90), and digital subscriber
line transceivers (G.994.1) as well as the related U.S. standards. He was a founder and technical editor of Communications Standards Review and Communications Standards
Summary 1990–2002. In 1995 and 2000 he won first prize
at the World Standards Day paper competition. In 2006 he
received a joint second prize in the IEC Centenary Challenge paper competition. He was Program Chair of the
Standards and Innovation in Information Technology (SIIT)
conference in 2001 (Boulder, Colorado), 2003 (Delft,
Netherlands), and 2007 (Calgary, Canada), and is a joint
Program Chair of SIIT 2009 (Tokyo, Japan). He is an adjunct
lecturer at the University of Colorado, Boulder. He learns
from his six delightful grandchildren, and applies his technical interests to research, writing, and teaching about
standards. A list of publications is available at http://www.
csrstds.com/klist.html.
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ITU-T KALEIDOSCOPE
The Architecture and a
Business Model for the
Open Heterogeneous Mobile Network
Yoshitoshi Murata, Iwate Prefectural University and National Institute of Information and
Communications Technology
Mikio Hasegawa, Tokyo University of Science and National Institute of Information and
Homare Murakami, Hiroshi Harada, and Shuzo Kato, National Institute of Information and
ABSTRACT
The mobile communications market has
grown rapidly over the past ten years, but the
market could reach saturation in the foreseeable
future. More flexible mobile networks that can
meet various user demands and create new market openings are required for further growth.
Heterogeneous networks are more suitable than
homogeneous networks for meeting a wide variety of user demands. There are two types of heterogeneous networks: a closed type, where
network resources are deployed and operated by
communication carriers, and an open type, where
network resources can be deployed not only by
existing operators, but also by companies, universities, and so on. It will be easy for newcomers to enter mobile businesses in an open
heterogeneous mobile network so many innovative services are likely to be provided through
cooperation between various companies or organizations. This article proposes a revised architecture for TISPAN-NGN, which corresponds to
heterogeneous networks and open mobile markets, and presents a new business model.
INTRODUCTION
1
This is one of the heterogeneous mobile networks.
The growth of the mobile communications market
has been both rapid and innovative as demonstrated by the rapid growth in the numbers of subscribers, terminals, services, and applications over
the past ten years. However, the growth rate of the
mobile market may slow within the next few years.
More flexible mobile networks that satisfy various
user demands and help open new market segments
are required for continuous market growth. Heterogeneous networks that use several kinds of radio
systems are more suitable for various user demands
than homogeneous networks using a particular
radio system. The progress of software-defined
radio (SDR) technologies and cognitive radio tech-
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nologies [1] has accelerated the development of
heterogeneous network technologies. The National
Institute of Information and Communication Technology (NICT) developed the multimedia integrated network by radio access innovation (MIRAI)1
architecture [2, 3], which has a common signaling
channel. It enables vertical handover between different terminals and different radio networks.
There are two types of heterogeneous networks: a
closed type, where network resources are deployed
and operated only by communications carriers, and
an open type, where network resources can be provided not only by existing operators, but also by
companies, universities, and so on.
In the Internet world, the market is open, and
new innovative services, such as Web 2.0, are created continuously by individuals working in any
number of locations around the world. The ability to develop new market opportunities is a powerful engine that helps to continuously expand
the overall market. The Ministry of Internal
Affairs and Communications (MIC) in Japan
released a mobile business activation plan [4, 5]
in September 2007. Its purpose is to help cultivate an open-type, mobile business environment
to promote new business models and invigorate
the mobile market for the benefit of users. Additionally, MIC has examined the practicality of a
mini-mobile base station that can be operated by
personal users without a radio operation license
[6]. In addition to in Japan, the same trend is
occurring elsewhere. For example, O’Droma in
Ireland proposes a ubiquitous consumer wireless
world (UCWW); in this wireless environment —
founded on a consumer-centric business model
— users are perceived as consumers rather than
subscribers [7]. O’Droma asserts that UCWW
benefits are very big and widespread.
These initiatives indicate that the administration favors the development of the open heterogeneous mobile network (OHMN).
The 3rd Generation Partnership Project
0163-6804/09/$25.00 © 2009 IEEE
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A reconsideration of
the mobile terminal
sales model will
separate the terminal
business from the
vertically integrated
business model.
Promoting the entry
of new MVNOs will
accelerate the
separation of the
network connection
business from the
access-network
business.
(3GPP) specifies the IP multimedia subsystem
(IMS) to provide several kinds of mobile services
in a universal mobile telecommunications system
(UMTS) to transparently connect mobile networks and the Internet [8]. IMS was introduced
as part of the Telecoms & Internet converged
Services & Protocols for Advanced NetworkNext Generation Network (TISPAN-NGN)2 [9,
10]. TISPAN-NGN is standardized based on the
vertical integration model, and communications
carriers totally control the entire network [11].
However, because TISPAN-NGN was designed
in accordance with a layer model [9], it is easy to
divide and open the business functions along with
the layer boundaries. In addition, because
TISPAN-NGN is a heterogeneous network [12,
13], it can easily be modified to become OHMN.
In this article, we explain how the TISPANNGN architecture can be changed to realize
OHMN, and how OHMN will change the circumstances of mobile business and enable innovative new services. The remainder of this article
is divided into three parts. First, we briefly
describe problems that must be overcome to
realize OHMN. Then, we describe a way to realize OHMN based on TISPAN-NGN. Finally, we
introduce some mobile business scenarios made
possible by the introduction of OHMN.
STEPS TOWARD REALIZING OHMN
REQUIREMENTS FOR OHMN
2
TISPAN-NGN is one of
the next-generation networks standardized by the
European Telecommunications Standards Institute (ETSI).
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The Japan MIC announced a mobile business
activation plan [4] in September 2007 aimed at
stimulating the mobile communications market
in Japan. This plan includes the following specific measures:
• Reconsider the sales model used for mobile
terminals.
–Introduce new charging plans that separate
the communications fee and the cost of the
mobile phone terminal.
–Clarify accounting rules for incentive payment systems used to sell mobile phones.
–Release the subscriber identification module (SIM) lock.
–Introduce a common mobile phone terminal platform that will be used by all carriers.
• Promote the entry of new mobile virtualnetwork operators (MVNOs).
–Re-amend MVNO business guidelines.
–Draw up a standard plan to enable the
resale of telecommunications service by
mobile network operators (MNOs).
–Consider MVNOs when regarding the
assignment of new frequencies.
• Promote a market environment that will
stimulate the mobile business.
–Strengthen policies for protecting consumers (create an authoritative source for
fee comparison and advice and provide a
complaint-resolution system).
–Develop ways to enable closer cooperation
between platforms (enable ID portability,
promote use of location information, and
push information delivery).
A reconsideration of the mobile terminal
sales model will separate the terminal business
from the vertically integrated business model.
Promoting the entry of new MVNOs will accel-
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erate the separation of the network connection
business from the access-network business.
We propose two additional measures to
encourage competition between carriers and
improve user convenience:
• The charging business should be separated
from other service provision businesses to
open up all layers to new business models.
• Depending on the user’s current circumstances, each user should be able to connect his or her mobile terminal to multiple
access networks regardless of the network
provider and radio system.
RESOLUTION OF PROBLEMS TO REALIZE OHMN
To open up the market, the following problems
must be resolved if the mobile communications
market is to be divided horizontally into five layers as described in the MIC plan:
1 MIC will use a notification system rather
than a license system to qualify carriers.
This might lower consumer confidence
regarding each carrier compared to what it
is in existing network operators.
2 The provided service quality (provided radio
system, service area coverage ratio, paging
rate, capacity, transmission quality, reliability,
and charge) could differ greatly among carriers.
3 It will be difficult for small network providers to register each user, check the user’s
creditworthiness, and charge the user.
4 It will be difficult for small network providers to manage the location of each terminal.
5 It will be difficult to assign a terminal ID to
establish a session because connected network providers will differ from one moment
to the next.
6 In addition, when choosing a mobile base
station suitable for a user’s policy from the
list of different communications carrier
base stations, there will be no unified node
that gathers and stores information regarding open radio channels, available QoS,
location, and base station positions.
THE OHMN
BUSINESS LAYER MODEL
The MIC believes that openness should be
included in each of the five layers: terminal layer,
network layer (physical network), connection-service layer (services related to communications),
platform layer (authorization and charging), and
contents and application layer (Fig. 1).
The core business of each layer is as follows:
• Terminal layer: manufacturing and selling
terminals.
• Network layer: deploying and providing
access networks.
• Connection-service layer: setting up a communication path between end terminals
through different access networks. MVNOs
are on this layer.
• Platform layer: user authentication and
charging.
• Contents and application layer: developing
and providing contents and applications for
mobile users.
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Business model 1.0
F
We define the
Business model 2.0
operations of a thirdContents and
application layer
Contents and
applications
party organization as
Contents and
applications
belonging to a
supervising layer.
Platform layer
Vertical
integration
model
tions of this thirdUbiquitous network
Broadband
All-IP
Connection
service layer
Fixed
communication
services
Mobile
communication
services
Mobile
communication
services
Because the opera-
FMC
Open
market
model
Network layer
party organization
will be outside of the
core mobile business
and are intended to
protect consumers,
the supervising layer
is external to the
Terminal layer
Mobile
terminals
Various ubiquitous
terminals
MIC five-layer model
but parallel to it.
Users
Various usage
Figure 1. MIC mobile business layer model.
The platform layer would be the most suitable
for solving the third problem mentioned above of
how small providers can effectively check the creditworthiness of customers and charge them for services. Likewise, to solve the fourth problem, the
platform layer is suitable for an ID writing business because only a credit business has an opportunity to write a unified ID such as a telephone
number to the SIM. Because the fifth problem is
related to connection services, the connection-service layer is the best place to solve it.
The following steps must be taken to solve
the first and second problems:
• Each mobile business provider must share
proprietary information openly.
• Service content, such as information on
charge rates, must be written in a way that
makes it easy to understand the differences
between service providers.
• A third party organization is required to
supervise and evaluate each mobile business provider and to provide evaluation
results openly.
These issues are in accordance with the third
measure of the MIC mobile business activation plan.
We define the operations of a third-party organization as belonging to a supervising layer. Because the
operations of this third-party organization will be
outside of the core mobile business and are intended
to protect consumers, the supervising layer is external to the MIC five-layer model but parallel to it
(Fig. 2). We propose that this model be used as the
OHMN business-layer model. In the future, we
expect informal evaluation sites to appear in addition
to formal sites. Concerning the sixth problem, business operators on the connection-service layer, who
connect with multiple-access networks or third-party
organizations, openly will gather available information concerning radio base stations.
Contents and
application layer
Platform
layer
Connection
service layer
Supervising
layer
Network layer
Terminal layer
Figure 2. OHMN business layer model.
TISPAN-NGN ARCHITECTURE
Next, we describe how the TISPAN-NGN architecture can be modified to realize OHMN.
IMS consists of the application layer, control
layer, and transport layer [9]. The access and terminal layers are underling IMS layers as shown
in Fig. 3.
The charging interfaces (R o and R f ) are
defined with the control layer, but no entity to
take charging information exists. IMS is based on
a network-operator-centric business model where
all services are managed by the control layer [10].
The TISPAN-NGN network structure is shown
in Fig. 4. Access systems, such as wideband codedivision multiple-access (WCDMA)3 cellular networks are connected to IMS through IP transport
networks. IMS uses Session Initiation Protocol
(SIP) [14] for session control. IMS in TISPANNGN consists of the following components:
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Application
servers (AS)
(reutilize common
functions)
Application layer
Session
management and
control
Control layer
Access
agnostic
Transport layer
HSS
CSCF
Cable
WiFi
3GPP radio
WiMAX
Access network
layer
Terminal layer
Figure 3. Layer model of TISPAN-NGN.
Rf/Ro
AS
Charging
functions
Rf/Ro
Core IMS
I/S-CSCF
HSS
P-CSCF
MGFC
MRFC
Resource and admission control subsystem
MRFP
UE
T-MGF
IP transport network (access and core)
SIP
H.248
Diameter
Figure 4. Network structure of TISPAN-NGN.
3
This is one of the 3G
mobile phone systems.
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• A proxy-call session control function (PCSCF), which configures IPSec tunnels for
each wireless network or fixed network
• An interrogation-CSCF (I-CSCF), which is
a gateway to another network
• A serving-CSCF(S-CSCF), which controls
sessions in a home network
• A home subscriber server (HSS), which
manages user IDs and locations
• A multimedia resource function controller
(MRFC), which manages media resources
and so on, and cooperates with multimedia
resource function processing (MRFP)
• A media gateway control function (MGCF),
which converts media between IP and circuit switching and cooperates with a trunk
media gateway function (T-MGF)
• User equipment (UE), which includes many
kinds of terminals
• An application server (AS), which includes
content servers and application servers
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TISPAN-NGN supports both online and offline
charging. For offline charging, charging information is sent from P/I/S-CSCF, MRFC, and so on,
to the charging data function (CDF) through the
Rf interface. For online charging, charging information is sent from the AS and MRFC to an
online charging system (OCS) through the R o
interface. In IMS, a public user identity, IP multimedia public identity (IMPU), which corresponds
to a subscriber’s telephone number, and an IP
multimedia private user identity (IMPI), which is
used to authorize the user for each network, are
assigned as a user identifier. In addition to these
user identifiers, the individual subscriber authentication key Ki, which is assigned when contracting,
and the uniform resource identifier (URI) of the
home-IMS network domain are stored in the IMS
subscriber identity module (ISIM). K i also is
stored in the HSS. As well as Ki, HSS includes the
following information:
• Subscriber registration (name, address, subscribed services, etc.)
• Subscriber preferences (forwarding setting,
etc.)
• Subscriber location
• Service-specific information
In TISPAN-NGN, the user cannot select a
communications provider depending on his or
her situation because the IMPI, IMPU, and K i
were stored in the ISIM when the user contracted with the communications provider. The selection of an access network is accomplished by
inserting the ISIM into a terminal that supports
each access system. In the case of W-CDMA,
the radio base station to connect to is selected
through radio network control (RNC). Therefore, it is impossible for a terminal to choose a
connecting radio base station from among the
base stations belonging to different carriers.
THE OHMN ARCHITECTURE
NETWORK STRUCTURE
The TISPAN-NGN five-layers model closely resembles the MCI five-layers model. The main difference is that the platform layer is divided from the
connection-service layer in the MCI model, whereas these layers are unified in the IMS layer model.
Furthermore, the access-network layer is divided
from the IP transport layer in IMS, but these two
layers are integrated in the MCI layer model.
Access networks are connected to IMS
through an IP transport network. This means
that access networks basically are separated from
IMS. Releasing the SIM lock makes the terminal
layer independent of IMS. In addition to making
connections between end to end (E2E), the purpose of the IMS control layer includes identifying each user. However, it does not include a
charging function. Dividing the user identification function from the IMS control layer and
providing a charging function results in the MIC
five-layer model, that is, the left side of the
OHMN-layer model shown in Fig. 2.
A third-party organization to monitor the
operation of each business provider is required
to protect the interests of users. A node for this
purpose corresponds to the right side of the
OHMN-layer model.
We propose that the:
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• Information stored in the HSS should be
divided between the home location server
(HLS), which holds location information
and forward-setting information and the
subscriber information server (SIS), which
holds all other information from the HSS.
• Charging function should become the entity
credit-management function (CMF).
• CMF should manage the SIS.
• Third-party organization server holds the
business information of credit-business providers, connection-service providers, and
application-service providers, such as management information and service information. For example, charging rates,
quality-of-service (QoS) levels, and service
areas are stored and opened when required.
This server is connected to S-CSCFs, CMFs,
and APs through the diameter protocol.
The proposed structure is shown in Fig. 5.
Contents and
application layer
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AP
Ro/Rf
Platform layer
SIS
CMF
Ro/Rf
HSS
Connection service layer
Third party
organization
server
S-CSCF
HLS
I-CSCF
SEQUENCE FLOW FOR REGISTRATION
Information related to radio conditions, user
information, and terms of service provision is
required to select a connection-service provider
and a connection base station, based on the user
policy. Such information must be gathered by a
terminal for the user to make such selections. A
connection-service provider will decide whether
to allow a user to connect to the network according to the user information, mainly the user’s
solvency. On the other hand, a user will decide
whether to connect to a service provider according to the terms of provision, mainly the charging rate and coverage area. The sequence flow is
shown in Fig. 6.
First, each base station (BS) periodically broadcasts the BS-ID and the P-CSCF-URI. Service
providers send their provision policies and content
depending on the circumstances to a third-party
organization server. These kinds of information
are evaluated and opened through their servers.
Second, a mobile terminal scans frequency
channels to receive the above information when
broadcast by its radio system. Each terminal
knows in advance which frequency channels to
scan. A terminal obtains required information
from third-party organization servers, together
with radio information regarding QoS, charging
rates, and the coverage area.
Third, a mobile terminal displays the name
and provision terms of each nominated connection-service provider whose provision terms and
radio conditions are consistent with a user’s policy. A user chooses one of the connection-service
provider displayed and requests to register.
Fourth, an S-CSCF decides whether to accept
the user’s request according to the user information that is asked of a CMF. As the result of an
OK, an S-CSCF sends the 401 unauthorized signal to a terminal.
Fifth, users go through user registration and
location registration. Then, a contracted accessnetwork carrier is registered in a SIS, and a
home S-CSCF-URI of a contracted carrier is registered to an HLS. When a user contracts with an
access-network carrier, a user inputs a password
instead of a signature, which has been registered
in a SIS. In some cases, an agent program is used
to automatically contract with a carrier.
P-CSCF
P-CSCF
P-CSCF
IP transport NW
3GPP
radio
Wi-Fi
WiMAX
Network layer
HLS: Home location server
SIS: Subscriber information server
CMF: Credit management function
Figure 5. Network structure of OHMN.
CHANGE IN THE MOBILE BUSINESS
BUSINESS CIRCUMSTANCES
We tried to divide the TISPAN-NGN vertical
integration business model from a function perspective. Another important consideration,
though, is that service providers for each layer
must make a profit to continue operating their
business. Providers in each layer should be able
to earn a profit in the following ways:
• Terminal manufacturers — by developing
and selling terminals.
• Access-network carriers — by charging for
communications by means of billing through
a connection-service provider and a creditservice provider on the platform layer.
• Connection-service providers who create
connections between terminals or between
a terminal and an AP server through a credit-service provider — by charging for their
services through a credit-service provider.
• Credit-service providers can receive a commission fee from content-applications providers, access-network carriers, and
connection-service providers based on the
credit provided.
• Application-service providers can charge for
the use of applications or content through a
credit-service provider.
• Third-party organizations can charge for
evaluating service providers directly.
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After the deploy-
Terminal
ment of OHMN,
BS-1
many new business
Broadcasting signal
(BS-ID, PCSCF-URI)
models will evolve to
Broadcasting signal ( )
enable profitability
under tough competitive conditions.
BS-2
P-CSCF-1
I/S-CSCF
Choose a
communication SIP Register (Ki, PCSCF-URI, CMF-URI)
service provider
become another
application service,
F
CMF
Diameter (Ki, OK/NG,
PW)
stances change, a
service is likely to
BEMaGS
Diameter (Ki)
As business circumtelecommunications
A
NG
OK
606 NG
Present NG
on the
terminal
401 unauthorized
SIP Register (RES, PW)
the same as content,
Web applications,
and so on.
HLS
Register
a location data
200 OK
to HLS
Ki: Individual subscriber authentication key
Figure 6. Control sequence how to choose a connected BS.
It should be possible for each provider to
remain profitable. After the deployment of
OHMN, many new business models will evolve to
enable profitability under tough competitive conditions. As business circumstances change, a
telecommunications service is likely to become
another application service, the same as content,
Web applications, and so on. For example, some
terminal manufacturers might develop new terminals designed to work directly with application or
content providers rather than access-network carriers. Most existing mobile terminals have the
same functions — there are only small differences
in the number of functions, quality, and design.
Innovative mobile terminals should be developed
specifically for some applications, for example:
• Cooperation with medical organizations
could lead to the development of mobile
terminals having a stethoscope or a sphygmomanometer, and so on, to enable remote
medical examination.
• Cooperation with an audio manufacturer
could enable development of mobile terminals having a 1-bit audio player to provide
super-real audio service.
A few of the new relationship models between
business players on each layer are shown in Fig.
7. In addition to providing access-network service, major communication carriers also will provide connection service and credit service in the
same way as current communication carriers.
Some MVNOs connect to private or general
company radio base stations and provide communications service at low rates. Furthermore,
some access-network carriers directly connect to
content servers or application servers.
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through their own WLAN to a connection-service provider and communicate with each other
in that way. Generally, users will be able to communicate with hot-spots. Their communications
bill is likely to become lower. If some connection-service providers provide a temporary connection service as a new connection service that
differs from a roaming service, each user could
choose an appropriate connection-service
provider to enable communications.
In the event of a major crisis that damages
some radio base stations, users could communicate through live base stations and report their
conditions. Because at least one access-communication carrier can cover a somewhat remote
area, users in such areas could communicate
through a radio base station of that carrier.
Therefore, service areas could be expanded without establishing new base stations.
CONCLUSION
PRIVATE CIRCUMSTANCES
The OHMN mobile network architecture will
help open the mobile market and will enable
users to connect their mobile terminal to the
preferred access-network carrier depending on
each user’s current circumstances. This network
architecture is based on TISPAN-NGN, which is
a strong NGN candidate. The OHMN business
model makes it easier for newcomers to develop
innovative terminals and services and offer them
to users. OHMN also will encourage the creation of many new business models and services.
Users should be able to enjoy these benefits at
reasonable rates. In general, we expect OHMN
to generate a positive spiral of activity in the
mobile market and continuously enhance the
development of this market.
The introduction of OHMN will change the circumstances of users. After buying a mobile terminal, a user would not be greatly concerned
about connection-service providers.
When in their homes, users will connect
[1] H. Harada, “Software Defined Radio Prototype Toward
Cognitive Radio Communication Systems,” Proc. IEEE
DySPAN ‘05, vol. 1, 2005, pp. 539–47.
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Small network carrier
and MVNO and AS
Major communication
company
Platform
layer
Communication
service layer
The OHMN business
model makes it
easier for newcomers
CMF
Major communication carrier
Contents and
application
layer
Small network
carrier and AS
F
to develop innovative
terminals and
AS-1
...
AS-1
...
AS-1
...
services and offer
them to users.
Major communication carrier
MVNO
...
OHMN also will
encourage the
Network
layer
3GPP
Wimax . . . W-LAN . . .
Wimax
W-LAN
...
W-LAN . . .
creation of many
new business models
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Terminal
layer
should be able to
enjoy these benefits
at reasonable rates.
Figure 7. Relationship between service providers.
[2] G. Wu, P. Havinga, and M. Mizuno, “MIRAI Architecture
for Heterogeneous Networks,” IEEE Commun. Mag.,
vol. 40, no.2, Feb. 2002, pp. 126–34.
[3] M. Inoue et al., “Novel Out-of-Band Signaling for Seamless
Interworking between Heterogeneous Networks,” IEEE
Wireless Commun., vol. 11, no. 2, 2004, pp. 56–63.
[4] Ministry of Internal Affairs and Communications,
“Mobile Business Revitalization Plan Released,” 2007;
http://www.soumu.go.jp/joho_tsusin/eng/Releases/Telec
ommunications/news070921_2.html
___________________
[5] Ministry of Internal Affairs and Communications, “Final
Report from Study Group on Mobile Business Released,”
2007;
http://www.soumu.go.jp/s-news/2007/
070920_5.html (in Japanese).
________
[6] Ministry of Internal Affairs and Communications, “Public Comment Invited on Draft Handling Policy for the
Utilization of Femtocell Base Stations in Relation to the
Radio Law, the Telecommunications Business Law, and
Relevant Ordinances,” 2008; http://www.soumu.go.jp/
joho_tsusin/eng/Releases/Telecommunications/news0802
______________________________
06_4.html
_____
[7] M. O’Droma and I. Ganchev, “Strategic Innovations
through NGN Standardization for a Ubiquitous Consumer Wireless World,” Proc. 1st ITU-T Kaleidoscope
Academic Conf., 2008, pp. 135–42.
[8] 3GPP TS 23.228, “IP Multimedia Subsystem (IMS) Stage
2,” 2005.
[9] T. Kovacikova and P. Segec, “NGN Standards Activities
in ETSI,” Proc. 6th ICN ‘07, 2007, p. 76.
[10] ETSI TR 180 001, “TISPAN_NGN; Release 1: Release
Definition,” 2005.
[11] A. Cuevas et al., “The IMS Service Platform: A Solution
for Next-Generation Network Operators to Be More
than Bit Pipes,” IEEE Commun. Mag., vol. 44, no.8,
Aug. 2006, pp. 75–81.
[12] F. Xu, L. Zhang, and Z. Zhou, “Interworking of WiMAX
and 3GPP Networks Based on ISM,” IEEE Commun.
Mag., vol. 45, no. 3, Mar. 2007, pp. 144–50.
[13] M. Matsumoto, “A Study of Authentication Method
on Fixed Mobile Convergence Environments,” Proc.
Telecommunication Net. Strategy Planning Symp., Nov.
2006, pp. 1–6.
[14] IETF RFC3261, “SIP: Session Initiation Protocol,” 2004.
BIOGRAPHIES
YOSHITOSHI MURATA [M] (y-murata@iwate-pu.ac.jp)
______________ received
his M.E from Nagoya University. He received his Ph.D. from
Shizuoka University. From 1979 to 2006 he was at NTT and
NTT DoCoMo, developing mobile communication systems,
terminals, and services. Since 2006 he has been a professor
on the Faculty of Software and Information Science, Iwate
Prefectural University, and a researcher at the National
Institute of Information and Communications Technology.
His research interests include mobile communications, sensor networks, sensor databases, and integrated media
communications. He is a member of IEICE and IPSJ.
M IKIO H ASEGAWA (hasegawa@ee.gaku.tus.ac.jp)
________________ received
B.Eng., M.Eng., and Dr.Eng. degrees from Tokyo University of Science in 1995, 1997, and 2000, respectively.
From 1997 to 2000 he was a research fellow at the
Japan Society for the Promotion of Science (JSPS). In
2000 he joined the Communications Research Laboratory, Ministry of Posts and Telecommunications, which
was reorganized as NICT in 2004. Since 2007 he is a
junior associate professor in the Department of Electrical
Engineering, Faculty of Engineering, Tokyo University of
Science. His research interests include chaos theory and
its applications, neural networks, optimization, and
mobile networks.
H OMARE M URAKAMI (homa@nict.go.jp)
__________ received his B.E.
and M.E. in electronic engineering from Hokkaido University in 1997 and 1999. He has worked at the Communications Research Laboratory, Ministry of Post and
Telecommunications since 1999, which has now been
now reorganized to National Institute of Information and
Communications Technology (NICT). He is currently a
senior researcher with the Ubiquitous Mobile Communications Group of NICT. He worked at Aalborg University
from 2003 to 2005 as a visiting researcher. His interest
areas are cognitive radio networking, IP mobility, new
transport protocol supporting wireless communications,
and naming schemes.
H IROSHI H ARADA (harada@nict.go.jp)
___________ is director of the
Ubiquitous Mobile Communication Group at NICT. After
joining the Communications Research Laboratory, Ministry
of Posts and Communications, in 1995 (currently NICT),
he has researched software defined radio (SDR), cognitive
radio, and broadband wireless access systems on the
microwave and millimeter-wave bands. He has also fulfilled important roles in international standardization
bodies, especially ITU-R WP5A, IEEE802.15.3c, and
IEEEP1900.4. He currently serves on the board of directors of SDR Forum and as chair of IEEE SCC41 and vicechair of IEEE 1900.4.
SHUZO KATO [F] (shu.kato@nict.go.jp)
___________ is a professor at the
Research Institute of Electrical Communications, Tohoku
University, Japan, and program coordinator, Ubiquitous
Mobile Communications, at NICT, working on wireless
communications systems R&D focusing on millimeter-wave
communications systems. He has been serving as vice-chair
of the IEEE802.15.3c Task Group working on millimeterwave systems standardization. He has published over 200
technical papers, holds over 75 patents (including one that
became a U.S. Department of Defense standard in 1998),
and co-founded the International Symposium on Personal
Indoor and Mobile Radio Communications (PIMRC). He is a
Fellow of IEICE Japan, and has served as an Editor of IEEE
Transaction on Communications, Chairman of the ComSoc
Satellite and Space Communications Committee, and a
Board Member of IEICE Japan.
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ITU-T KALEIDOSCOPE
Differential Phase
Shift-Quantum Key Distribution
Hiroki Takesue, Toshimori Honjo, Kiyoshi Tamaki, and Yasuhiro Tokura, NTT Corporation
ABSTRACT
Quantum-key distribution has been studied as
an ultimate method for secure communications,
and now it is emerging as a technology that can
be deployed in real fiber networks. Here, we
present our QKD experiments based on the differential-phase-shift QKD protocol. A DPSQKD system has a simple configuration that is
easy to implement with conventional optical
communication components, and it is suitable
for a high-clock rate system. Moreover, although
the DPS-QKD system is implemented with an
attenuated laser source, it is inherently secure
against strong eavesdropping attacks called photon number-splitting attacks, which pose a serious threat to conventional QKD systems with
attenuated laser sources. We also describe three
types of single-photon detectors that are suitable
for high-speed, long-distance QKD: an up-conversion detector, a superconducting single-photon detector, and a sinusoidally gated InGaAs
avalanche photodiode. We present our recordsetting QKD experiments that employed those
detectors.
INTRODUCTION
Sending confidential information over the Internet is becoming more common; therefore, network security must be strengthened. So far,
public-key cryptosystems— such as RSA, a cryptosystem invented by Rivest, Shamir, and Adleman — have been used widely. However,
because the security of public-key cryptosystems
depends on the difficulty of solving certain mathematical problems such as the factorization of
large numbers, those cryptosystems could
become vulnerable if great advances are made in
mathematics or computing. In addition, it is well
known that RSA cryptosystems can be broken if
an eavesdropper (who typically is called Eve in
the field of cryptography) has a quantum computer because then he or she can solve the factorization problem efficiently. Quantum
cryptography, or quantum-key distribution
(QKD), offers network security that is not vulnerable to theoretical or technological advances
[1]. In the last ten years, much progress has been
made on fiber-based QKD systems: the key distribution distance has exceeded 100 km, the key
rate has continued to increase, and various new
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protocols have been proposed. Currently, it is
expected that QKD can be the first commercial
application of quantum information science. In
this article, we describe the NTT Corporation
research on QKD systems. Our system is based
on a protocol called differential-phase-shiftQKD (DPS-QKD), which was invented during a
collaboration by NTT and Stanford University
[2]. In the next section, we describe the general
concept of QKD, and we explain the features of
the DPS-QKD protocol. We then present several DPS-QKD experiments with various singlephoton detectors. This section includes a
description of a record-setting 200-km QKD
experiment using superconducting single-photon
detectors (SSPDs). The key open issues related
to DPS-QKD are discussed in the following section. The final section summarizes the article.
QUANTUM-KEY DISTRIBUTION
It is a well-established fact that one-time pad
cryptography is unconditionally secure if the key
length is equal to that of the data to be encrypted [1]. The problem is to find a way for a sender
(Alice) and a receiver (Bob) in two distant locations to share the key. The purpose of a QKD
system is to provide unconditionally secure keys
between Alice and Bob. By employing keys distributed using a QKD and one-time pad cryptography, Alice and Bob can achieve
unconditionally secure communication.
The first QKD protocol was invented by Bennett and Brassard in 1984 and now is widely
referred to as the BB84 protocol [3]. In this protocol, Alice modulates photons with random
data and sends them to Bob through a “quantum
channel.” Here, Alice randomly chooses one
from two non-orthogonal modulation bases (for
example, in polarization coding, the vertical/horizontal basis or the right-hand circular/left-hand
circular basis). Bob measures the received photons with a measurement basis that is randomly
chosen from two non-orthogonal measurement
bases. Then, Bob discloses the basis that he used
for each photon through a “classical channel,”
which is a conventional communication line.
Alice’s modulation data and Bob’s measurement
outcome correlate only when their bases coincide so they can share a random bit sequence by
extracting the events with matched bases. To
steal the information on the key, Eve must per-
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Intensity modulator
Bob
Phase modulator
Single photon detectors
The DPS-QKD and
COW are now
Attenuator
Alice
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referred to as distributed-phase refer-
Laser
ence protocols, in
Quantum channel
(optical fiber)
1-bit delayed
interferometer
which the coherence
of the sequential
pulses plays a crucial
Figure 1. DPS-QKD setup [2].
role in security.
These two protocols
form a measurement on the photons in the quantum channel. Such a measurement inevitably
changes the quantum state of the photons, which
results in a discrepancy between Alice and Bob’s
data when their bases match. Therefore, Alice
and Bob can detect Eve by monitoring the error
rate of their quantum channel transmission.
BB84 is the protocol whose security has been
studied most intensively. The unconditional
security of the BB84 protocol was proved for
several implementations with ideal single-photon
sources (SPSs) and attenuated laser sources [4].
Since the early 1990s, many fiber-based QKD
experiments have been undertaken based on the
BB84 protocol. Although the BB84 protocol
must be implemented with an ideal single-photon source, those early experiments used attenuated laser sources as “pseudo single photon
sources.” Since the early 1990s, it has been
known that the performance of BB84 systems
with attenuated laser sources was severely limited by an eavesdropping attack called a photonnumber-splitting (PNS) attack [4]. Because the
number of photons emitted from an attenuated
laser source has a Poissonian distribution, there
is a finite probability that the source emits two
or more photons in a pulse, which means that a
complete copy of the quantum information in
theory is available. In a PNS attack, Eve performs a quantum non-demolition (QND) photon-number measurement for each pulse, and if
she finds a multi-photon pulse, she extracts one
photon, stores it in her “quantum memory,” and
sends the others to Bob. Then, after Bob has
disclosed the measurement basis, Eve measures
the photons in her quantum memory so that she
can obtain information that correlates with Alice
and Bob’s information without causing errors.
Currently, there are two kinds of efforts
whose aim is to make QKD with attenuated
laser sources secure. The first involves implementing the BB84 protocol with “decoy states”
[5]. In this scheme, “decoy pulses,” whose average photon number is different from that of the
signal pulse, are inserted randomly. The PNS
attack changes the ratio of the count probability
between the signal and decoy pulses, and so it
can be detected by monitoring the detection rate
of the signal and decoy pulses. Although this
scheme is proven to increase significantly the
unconditionally secure key distribution distance,
the introduction of a decoy complicates the signal processing.
The other effort involves inventing QKD protocols that are inherently secure against a PNS
attack. The DPS-QKD protocol is one such protocol. Other protocols include the Bennett 1992
(B92) protocol with a strong reference pulse [6]
and coherent one-way compliance on the Web
(COW) [7]. The DPS-QKD and COW are now
referred to as distributed-phase reference protocols, in which the coherence of the sequential
pulses plays a crucial role in security. These two
protocols are suitable for high-speed key distribution and so are expected to be employed in
next-generation QKD systems. In the following
section, we explain the principle of the DPSQKD protocol.
are suitable for highspeed key
distribution and so
are expected to be
employed in
next-generation
QKD systems.
DPS-QKD PROTOCOL
Figure 1 shows an example of a DPS-QKD system configuration. Alice modulates the intensity
of a continuous light from a laser into a pulse
train and modulates the phase of each pulse randomly by {0,U}. She then attenuates the pulse
train so that the average photon number per
pulse is much smaller than 1 and sends them to
Bob through an optical fiber. Bob inputs the
received pulse train into a 1-bit delayed interferometer whose delay time is set so that it is the
same as the pulse interval. The phase of the
delayed interferometer is adjusted so that the
photons are output from port 1 (2) when the
phase difference between two adjacent pulses is
0 (U). Bob records the time instances in which
he observed the photons, and which detector
clicked in those instances. Then, Bob sends the
time instances to Alice through classical communication. With the time instance information and
original modulation data, Alice knows which
detector clicked in those instances at Bob.
Therefore, by allocating phase difference 0 (U)
as bit 0 (1), they can share an identical bit string
that can be used as a secret key.
This protocol is inherently secure against a
PNS attack. Because the information is encoded
to the phase difference between pulses, Eve cannot obtain any information using a conventional
PNS attack based on a QND measurement of
each pulse. Although Eve can partially obtain
the information by using a PNS attack with a
QND measurement on two or more pulses, a
QND measurement of a segment of sequential
coherent pulses breaks the coherence at the
edge of the segment, which results in errors in
Bob’s measurement [8]. Thus, because the PNS
attack induces errors in a DPS-QKD system, this
attack can be detected and thus, is not effective
against the DPS-QKD protocol.
The DPS-QKD protocol is proven to be
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secure against general individual attacks, in
which Eve can undertake any possible attack
against each photon whose quantum state is
spread over many pulses [8]. Similarly, with the
BB84 protocol with a single-photon source or
decoy states, the secure-key rate of the DPSQKD scales linearly with the transmission loss,
implying that long-distance key distribution is
possible without being hampered by a PNS
attack.
As seen in Fig. 1, an advantage of DPS-QKD
is that most of the optical components are the
same as those used for current optical communication systems. Regarding the photon source, we
usually employ an external cavity diode laser,
which can be replaced with a narrow line-width
distributed-feedback (DFB) laser. The intensity
and phase modulators are those used for optical
communication. As in differential-phase, shiftPPLN waveguide
Pump (1319 nm)
Long-pass filter
Dichroic mirror
Signal (1550 nm)
WDM coupler
Lens
Prism
Fiber
Free space
Lens
Si APD
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keying optical communication systems, we use a
one-bit delayed interferometer fabricated using
planar-lightwave-circuit technology. The biggest
difference from optical communication systems
is the use of single-photon detectors at Bob’s
site, which we explain in the next section.
DPS-QKD EXPERIMENTS WITH
VARIOUS SINGLE-PHOTON
DETECTORS
Single-photon detectors are the key components
for QKD systems. In particular, a low dark-count
property is important for long-distance QKD. To
fully utilize the high-repetition-rate pulses used
in a DPS-QKD system, a high counting rate with
a small dead time also is required. In the 1.5 Rm
band, InGaAs avalanche photodiodes (APD)
were used conventionally for single-photon
counting. However, InGaAs APD-based singlephoton detectors have a larger dark-count rate
than silicon APD-based single-photon detectors
for the short wavelength band. In addition,
InGaAs APDs usually must be operated in a
gated mode to avoid erroneous counts caused by
afterpulsing, and the gate frequency is limited to
at most 10 MHz.
UP-CONVERSION DETECTOR
Figure 2. Up-conversion detector [9].
(a)
Bias current
Incident photon
Hot spot
NbN
4 nm
100 nm
Counts
(b)
SSPD
Time (50 ps/div.)
Figure 3. Superconducting single photon detector (SSPD) [11]: a) operating
principle; b) histogram of photon arrival time when 10-ps pulses were input.
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To overcome the problems with the conventional
InGaAs APD, we developed a single-photon
detector based on frequency up-conversion in
collaboration with Stanford University [9]. A
schematic diagram of our up-conversion detector
is shown in Fig. 2. A 1.5 Rm signal photon is
combined with a 1.3 Rm strong pump light with
a wavelength division multiplexing (WDM) coupler and input into a periodically poled lithium
niobate (PPLN) waveguide. In the PPLN waveguide, the 1.5 Rm photon is wavelength-converted
to a 0.7 Rm photon by a sum frequency generation process. Then, the up-converted photon
passes through optical filters to suppress the
pump and is received by a single-photon detector based on a silicon APD. Due to the high
quantum efficiency, low dark-count rate, and
non-gated mode operability of the silicon-based
single-photon detector, we can use this scheme
to construct a non-gated, high-sensitivity, singlephoton detector for the 1.5 Rm band. We have
reported an overall quantum efficiency of 46
percent with our up-conversion detector [9]. We
undertook DPS-QKD experiments using up-conversion detectors with a 1 GHz clock frequency
and successfully generated secure keys over 100
km of fiber with a 166 bit/s key rate [10].
With the up-conversion detectors, the maximum
clock frequency was limited to 1 GHz because of
the relatively large timing jitter of the silicon
APDs. To increase the clock frequency to 10
GHz, we used an SSPD developed by the
National Institute of Standards and Technology
(NIST) [11]. Figure 3a shows the photon-detection mechanism of the SSPD. An NbN superconducting wire is current-biased slightly below
its critical current. When a photon hits the wire,
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a resistive hot spot is formed. Then the current
density around the spot increases and eventually
exceeds the critical current. As a result, a nonsuperconducting barrier is formed across the
entire width of the wire, and a voltage pulse is
output. By measuring the time position of the
voltage pulse, we can measure the photon arrival
time with a high timing resolution. The SSPD
has a very low dark-count rate because of its
low-noise, cryogenic operation environment.
Moreover, because the energy relaxation time
constants of excited electrons in superconductors
are very short, the SSPD has very good timing
resolution. Figure 3b shows a histogram of the
photon arrival time measured with the SSPD
when 10-ps pulses were launched. The full width
at half maximum of the jitter was only 60 ps and
fitted very well with Gaussian.
We performed a 10 GHz clock DPS-QKD
experiment with SSPDs [11]. A highly phasecoherent 10 GHz clock pulse train was obtained
by intensity-modulating a continuous light from
an external cavity laser diode using an electroabsorption modulator. The quantum efficiency
and the combined dark-count rate of the two
SSPDs were 1.5 percent and 50 Hz, respectively.
The secure-key-generation rate as a function of
fiber length is shown in Fig. 4. We successfully
generated a 12-bit/s secure key over 200 km of
fiber, which set the record for PNS-secure, longdistance QKD. In addition, we observed a
secure-key rate of 17 kb/s at 105 km, which is
two orders of magnitude larger than the key rate
obtained with up-conversion detectors at 100
km.
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Result with
up-conversion detectors
100
10-1
0
50
100
150
200
Fiber length with 0.2 dB/km loss (km)
250
Figure 4. Secure key rate as a function of fiber length [11]. Note that here
“secure key” means that the key is secure against general individual attacks.
Filled squares: fiber transmission, empty squares: simulated points with
optical attenuator, triangles: results obtained using 1 GHz clock system with
up-conversion detectors [10].
Proton input timing
SINUSOIDALLY GATED
INGAAS AVALANCHE PHOTODIODE
Although it is apparent from the above experimental results that the up-conversion detector
and the SSPD are very powerful tools for QKD,
there are several drawbacks regarding these
detectors. The up-conversion detector has a very
narrow bandwidth (typically less than 1 nm) and
requires precise temperature control for a PPLN
waveguide. The SSPD requires 4-K cooling
equipment, which currently is both expensive
and bulky. Therefore, the development of highspeed, semiconductor-based, single-photon
detectors is very important if we are to realize
compact, inexpensive QKD systems.
With this motivation, a group from Nihon
University developed a high-speed, single-photon detector based on InGaAs APD [12]. In this
scheme, whose configuration is shown in Fig. 5,
a sine-wave gate signal is applied to the APD
instead of the rectangular gate used in a conventional gated mode. The point is that the sinusoidal-gate signal easily can be discriminated
from an avalanche signal in the frequency
domain: the gate signal is suppressed efficiently
simply by using a band-rejection filter. As a
result, this scheme can detect a small avalanche
signal that is generated with a relatively small
gate signal. The reduction in the gate voltage
leads to a significant reduction in afterpulse
probability, and thus we can increase the gate
frequency. This scheme was used to achieve a
gate frequency of up to 800 MHz with a reason-
Sine wave gate
Photon
Filter
Figure 5. InGaAs/InP avalanche photodiode with sinusoidal gating [12].
able quantum efficiency (8.5 percent) and darkcount probability (10–5) [12].
We used single-photon detectors based on
sinusoidally gated InGaAs APDs for a 500-MHz
clock DPS-QKD experiment. We obtained a 1.5Mb/s shifted key with an error rate of 2.3 percent over 15 km of fiber, with which we can
extract a secure key with a rate of 330 kb/s [13].
SUMMARY AND FUTURE WORK
We described the recent progress on DPS-QKD.
The principle of the DPS-QKD protocol was
explained, and the security against a PNS attack
was discussed briefly. Then, we reported QKD
experiments with three types of single-photon
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An important topic
for the field of QKD
is QKD system standardization. In the
standardization process, we must take
account of many
aspects of QKD. For
example, the classification of the security
levels of various QKD
protocols is a crucial
issue in terms of
differentiating QKD
from conventional
cryptography
systems.
detectors. Note that the detectors introduced
here also should prove useful for improving the
performance of other high-clock-rate QKD systems. We also discussed the key open issues
related to DPS-QKD. We hope that our DPSQKD system will provide rapid and secure longdistance communication for next-generation
networks.
An important open issue related to DPSQKD is its unconditional security. As mentioned
previously, the DPS-QKD protocol was proven
secure against general individual attacks, where
Eve’s attack is limited to attacks on individual
photons. However, unlike previous protocols
such as BB84 [3] and B92 [6], the unconditional
security of the DPS-QKD protocol has not yet
been proven. This means that there may be
attacks on DPS-QKD that are more efficient
than individual attacks, and a more comprehensive security analysis of the DPS-QKD protocol
is required.
An important topic for the whole field of
QKD is QKD system standardization. In the
standardization process, we must take account of
many aspects of QKD. For example, the classification of the security levels of various QKD protocols is a crucial issue in terms of differentiating
QKD from conventional cryptography systems.
The standardization of components that are particular to QKD, such as single-photon detectors,
should also be taken into consideration. Moreover, it is important to standardize the interfaces
for connecting different types of QKD systems.
Currently, standardization work is under way in
Europe (http://www.secoqc.net/).
ACKNOWLEDGMENT
This research was undertaken in collaboration
with many people and institutions. We particularly wish to thank Kyo Inoue and Yoshihisa
Yamamoto for their helpful guidance on QKD.
We also thank M. M. Fejer, Edo Waks, Eleni
Diamanti, Carsten Langrock, Qiang Zhang, Kai
Wen, Sae Woo Nam, Robert H. Hadfield,
Shuichiro Inoue, Naoto Namekata, and Go Fujii
for their important contributions to this work.
This research receives financial support from the
National Institution of Information and Communications Technology (NICT) of Japan and the
CREST program of the Japan Science and Technology Agency (JST).
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on a Sinusoidally Gated InGaAs/InP Avalanche Photodiode,” Applied Physics Lett., vol. 91, 2007, 011112.
BIOGRAPHIES
HIROKI TAKESUE [M‘00] (htakesue@will.brl.ntt.co.jp)
______________ received
his B.E., M. E, and Ph. D. degrees in engineering science
from Osaka University, Japan, in 1994, 1996, and 2002,
respectively. He joined NTT Laboratories in 1996, where he
has engaged in research on lightwave frequency synthesis,
optical access networks using wavelength-division multiplexing, and quantum communication. From 2004 to 2005
he was a visiting scholar at Stanford University, California.
He is currently a member of the telecom-band entanglement project, CREST, Japan Science and Technology Agency. He is a member of the Japan Society of Applied
Physics.
TOSHIMORI HONJO received his B.S. and M.S. degrees in information science from Tokyo Institute of Technology, Japan,
in 1996 and 1998, and his Ph.D. degree in engineering
from Osaka University in 2007, respectively. In 1998 he
joined NTT Software Laboratories, Musashino, Japan, where
he was engaged in research on design and implementation
of a TCP/IP protocol stack for secure and mobile communication. In 2003 he moved to NTT Basic Research Laboratories, Atsugi, Japan. Since then he has been engaging in
research on quantum optics and quantum information. He
is a member of theAmerican Physical Society (APS).
KIYOSHI TAMAKI received his M.Sc. degree from Tokyo Institute of Technology and his Ph.D. degree in theoretical
physics from the Graduate University for Advanced Studies
(SOKENDAI), Japan. After receiving his Ph.D. degree, he
worked at the Perimeter Institute for Theoretical Physics,
Canada, and the University of Toronto, Canada as a postdoctoral fellow. He joined NTT Basic Research Laboratories
in 2006, where he has engaged in theoretical analysis of
quantum key distribution, especially its security proof.
YASUHIRO TOKURA received his B.S., M.S., and Dr. in Arts and
Science from Tokyo University in 1983, 1985, and 1998,
respectively. In 1985 he joined NTT Basic Research Laboratories, Kanagawa, Japan. Since then he has been engaged
in research of condensed-matter physics and transport theory in low-dimensional systems. Currently, he is an executive manager of the Optical Science Research Laboratory as
well as a group leader of Quantum Optical State Control
Research Group of NTT Basic Research Laboratories. He is a
member of the Physical Society of Japan and the Japan
Society of Applied Physics.
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ITU-T KALEIDOSCOPE
Open API Standardization for the
NGN Platform
Catherine E.A. Mulligan, University of Cambridge
ABSTRACT
Next-generation networks promise to provide
a richer set of applications for the end user, creating a network platform that enables the rapid
creation of new services. Significant progress has
been made in the standardization of NGN architecture and protocols, but little progress has
been made on open APIs. This article outlines
the importance of open APIs and the current
achievements of the standards bodies. It concludes with a brief set of issues that standards
bodies must resolve in relation to these APIs.
INTRODUCTION
Next-generation networks (NGNs) are meant to
“enable a richer set of applications to the enduser” [1], creating a network platform that enables
the rapid creation of new services without a
requirement to add new infrastructure. Significant
progress has been made in the standardization of
NGN architecture and protocol implementation
in several different standards bodies. However,
few developers are creating innovative applications for the NGN platform. This article outlines
the importance of such APIs, describes what has
been achieved so far in the standards bodies, and
concludes with a brief set of issues that standards
bodies must resolve in relation to open APIs.
The creation of developer communities for
NGNs is critical to ensuring the success of this
platform and thus a return on the investments of
member companies building platforms from the
standards. Currently, open APIs that are standardized for the NGN platform are poorly
defined in comparison to the requirements,
architecture, and protocols. In contrast, de facto
APIs such as Google’s OpenSocial enable developers to rapidly create innovative applications.
Several lessons from Google’s approach can
inform the direction of open APIs for the NGN
platform, their standardization, and a way of
attracting developers to them.
PLATFORM ECONOMICS AND THE
NGN
Platforms are designed to bring together distinct
groups of customers, who benefit from having
each other on the same platform, for example,
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“a shopping mall brings together shoppers and
stores” [2]. A multisided platform brings together “two or more distinct groups of customers,”
acting as an intermediary that reduces the transaction costs for the groups of customers [2]. A
software platform acts as an intermediary
between developers and customers through the
provision of APIs, distributing the costs for
application development. Two main business
models have been applied to the development
and application of these APIs; user pays or
developer pays.
Two well-known examples of two-sided platforms are the PC operating system (OS) and the
console gaming platform. A company develops
an OS and exposes its capabilities to third-party
developers through free APIs, who then establish a range of attractive applications. End users
then select their OS, based on the available
applications. Therefore, APIs are critical to the
success of an OS. On the other hand, console
platforms are more tightly integrated, with developers paying licensing fees for access to the
APIs that are required to develop games for a
company game platform. End users receive heavily subsidized consoles and pay relatively high
prices for games.
Traditional mobile phone networks have
more complicated platform models. Software
platforms for mobile devices are multisided platforms, incorporating many different players
including the handset manufacturer, OS manufacturer, network operator, and end user. This
added complexity has led to difficulties for
developers in moving their applications onto
vendors’ handsets. As a result, there are limitations on the type and number of mobile applications that have become popular; generally this is
because the “the developer is forced to go
through the operator middleman, the operator’s
entire organization, to avoid internal competition” [3]. The diagram in Fig. 1 illustrates the
complex nature of the ecosystem that exists
around the mobile handset.
One exception to the traditional mobile network model is iMode, which broke out of the
traditional multisided platform for network
applications and provided a network as a common platform between content providers and
end users: “we leave content creation to the Service Providers who excel at that, DoCoMo concentrates on our system for collecting fees, our
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Through exposing
Application and
content providers
APIs, eBay leverages
its end users to
encourage the
Applications
and content
establishment
of a developer
Royalties
Software platform
operating system
middleware
Software
community on their
Handset
makers
Handsets
Network
operator
Handsets, voice
and data services
Consumers
platform. Therefore,
eBay’s open APIs
attract higher
numbers of end
users onto their
Figure 1. Platform ecosystem for mobile phones, taken from [2].
platform, creating a
virtuous circle.
platform, and designing our data warehouse” [4].
DoCoMo takes a percentage of all the fees
charged by content providers and also concentrates on providing “marketing data to content
providers” [4].
It would appear that other operators could
replicate iMode quite easily, in particular with
regard to the emergence of mobile broadband.
However, the success of iMode is difficult to
replicate for other operators because the economics of the mobile communications industry
have shifted. iMode depended upon important
cooperation between the handset manufacturers
and NTT DoCoMo at nearly every stage and
also upon the development of iHTML. Players
in today’s communications industry must ensure
that open APIs designed to expose the functionality of the NGN platform are used by developers in conjunction with Internet technologies.
Yet the very innovative capacity displayed on the
Internet platform is in itself a complex system of
interacting elements. With technical convergence
between mobile and Internet technologies, it is
necessary for different players in the system to
work together to create the virtuous circle for
the NGN platform. Using what Chesbrough [5]
defines as “Open Innovation,” operators and
other players can harness one another’s capabilities to trigger the creation of developer communities for the NGN platform.
As an example, the area of voice over IP
(VoIP) communications has not followed an
established trajectory as many in the industry
expected it would; telecommunications vendors
took the more traditional standardization path
and created the IP multimedia subsystem (IMS),
whereas other players used the potential of
Internet technologies to create proprietary systems that have proved to be tremendously popular, such as Skype. Therefore, there is no
“well-defined end-point” for these technologies.
Instead “the broad parameters are visible: the
rise of demand for global communications,
increased availability of broadband (fixed and
mobile), multiple [peer-to-peer] P2P networking
models, growing technological literacy among
users” [6]. The established players have high levels of R&D investment to protect, whereas new
entrants to these markets fight to gain small
patches of ground among a plethora of offerings
on the Internet and the Web. “The dominant
design isn’t visible yet — instead there is a rich
fermenting soup of technological possibilities,
business models and potential players from
which it will all gradually emerge” [6]. It is
impossible for anyone to predict which technology or application will be the successful one.
Through working together in innovation incubators, all of the players succeed together; therefore players who participate in the NGN
standardization forums also should work together to secure the creation of a developer community. Excellent examples of this are the
application stores created by Google and Apple
for developers on their respective mobile platforms. The success of such concepts in capturing
the attention of end users has led to new, platform-independent initiatives, for example,
AT&T’s devCentral, Vodafone’s Betavine, as
well as Ericsson Labs.
Meanwhile, the Internet itself has seen the
development of “new” styles of platforms; essentially service marketplaces such as eBay, Facebook, and Google that expose APIs to
developers who create applications that enhance
and extend the original platform. For example,
eBay provides the marketplace for developers
and end users to meet for shopping and trading
focused Web services; through exposing APIs,
eBay leverages its end users to encourage the
establishment of a developer community on their
platform. Therefore, eBay’s open APIs attract
higher numbers of end users onto their platform,
creating a virtuous circle.
All of these Internet-based platforms provide
APIs to developers that are to a greater or lesser
degree based on existing Internet standards and
business models, that is, the separation of content from access; “consumers buy a specified
number of megabits per second and that’s all
they buy. All the content is provided by independent players. There is no relation between the
internet provider and the content, service and
application providers.” [3]. The platforms such
as eBay that have evolved on the Internet, however, are due to high quality APIs that enable
developers and end users to meet on the common platform of eBay. Table 1 displays some
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Platform
Description
Example APIs
Example applications
Google
Search
Gadgets, Gears, Maps, Calendar, OpenSocial
Scenic Spot Sharing, Daylight Map, Authentication
Facebook
Social network
FBML, FQL
FunWall by Slide, Flickster
eBay
Auction
marketplace
User profile and reputation, buying application,
checkout, user messaging, and CRM
Speed Bid 2.0, eBay Alerts, eBay mobile
Amazon
Sales of goods
E-commerce service, flexible payments service
myCheckout, Bookweave, GiftPrompter
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Table 1. Some platforms that have been built on the Internet, APIs provided, and example applications.
platforms that were built on the Internet, the
APIs provided, and sample applications.
Many of the software platforms provided
on the Internet are proprietary; an application
developed for a social networking site such as
Facebook must be rewritten before it can run
on other similar platforms, for example, Orkut
or LinkedIn. Interconnection issues have not
been considered necessary to address within
the scope of these platforms yet. With the
advent of social networks, however, duplication of end-user information contained on
these sites has been identified as a problem
that must be fixed to ensure proper functioning of the market for application developers
and end users.
This movement toward user-centric, rather
than service-centric only, application development has led to a greater understanding of the
need for some level of coordination between
platforms serving at least the social networking
community. Google OpenSocial is the clearest
example — a group of over 30 companies that
have joined together to provide open APIs for
the social networking community. These APIs
are intended to be the “de facto standard” for
social networks and are designed to be used in
conjunction with other APIs, for example, the
Android software development kit (SDK) for
mobile phone development or Extensible Messaging and Presence Protocol (XMPP) for P2P
communication.
The convergence of information technology
(IT), telco, and broadcasting networks within the
framework of the next five years will not be just
a merging of access technologies or network
rationalization for operators through IP technology, nor will it be solely about providing converged services. Of fundamental importance in
the convergence of these different industries will
be the merger of the different types of platform
economics they exhibit.
With the advent of NGN, the network
becomes a platform providing distributed network intelligence. Therefore, the creation of
open APIs are crucial to the development of
NGN; the significant investments that have
been made in the standardization of requirements, architecture, and protocol implementation in the standards bodies active in the NGN
area must be protected through the creation of
APIs that encourage developers to build applications for these networks. Developers do not
want to be required to redevelop their applications for each service provider; thus, there is a
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need to standardize at least some basic APIs
for NGN. Failure to provide compelling APIs
for these networks will force the development
community to other APIs that may not use the
architecture or protocols described by the traditional telecommunications standardization bodies such as the 3rd Generation Partnership
Project (3GPP), Open Mobile Alliance (OMA),
or Telecoms & Internet converged Services &
Protocols for Advanced Network (TISPAN),
and so on.
The NGN will provide a multisided, multivendor platform in an all-IP environment, with
ecosystems that are potentially more complex
than the existing mobile network ecosystems.
The sheer complexity of the platform provided
by an all-IP NGN means that “one industry
alone” cannot provide all the applications and
content that end users want [4]. Vendors, service
providers, network operators, and handset manufacturers must rely on third parties in order to
develop compelling applications. Quite simply,
end users do not use platforms that do not provide attractive applications [2]. The APIs that
are made available to developers directly defines
the quality of applications developed for a particular platform. The current APIs standardized
within an NGN context severely limit creativity
and innovation on the NGN platform; if a developer is faced with no library or API, the likelihood of innovative services being created is low
[2]. This must be addressed within the standardization bodies as soon as possible.
EXISTING APIS IN NGN STANDARDS
Standards bodies working on NGN issues have
focused mainly on traditional telecommunications standardization issues so far: stage 1
(requirements), stage 2 (architecture), and stage
3 (protocol definition). The development of
open APIs, however, has received significantly
lower attention. Standardization bodies have
tended to focus heavily on the development of
higher speed access technologies, for example,
long-term evolution (LTE), or worldwide interoperability for microwave access (WiMAX),
rather than open APIs for developers. To ensure
that applications of sufficient creativity and innovation are created on the all-IP architecture
defined so far, the development of a basic standardized set of APIs must be considered a priority in the next five years.
Work has been completed within the Java
community to provide service level APIs to
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developers, including Java specification request
(JSR) 281 IMS Services API and JSR 289 Session Initiation Protocol (SIP) Servlet v1.1.
These provide good development environments
for IMS networks but only through Java technology. All developers that wish to use these
require a J2EE environment to run them and
require a reasonable understanding of the IMS
core network to be able to develop applications.
Generally, developers must negotiate to be
inside a service provider’s network before they
will be allowed access to the IMS service control
(ISC) interface; in this way, these APIs essentially provide an IN-style SDK for developers.
The requirement to negotiate with service providers to gain access to their network slows
down the creation of a large developer base,
limiting the applications developed and therefore, limiting the number of end users. As a
result, APIs are required for third-party developers that expose basic network functionality
while not exposing sensitive interfaces such as
the ISC; that is, they must be “designed to serve
in a world where the majority of value-added
services are hosted outside operator environments” [7].
Meanwhile, the OMA has established a
robust framework for Web services, for example,
the OMA Web services enabler (OMA OWSER)
and mobile enablers, for example, Presence; yet
they have not produced any APIs for these
enablers. This is a critical issue because without
APIs, these enablers do not provide impetus for
developer communities to use the functionality
defined within them.
One standardization effort for the creation of
APIs between the IT and telecommunications
industries has been the Parlay group, which is
responsible for the creation of Parlay Web service APIs, specified within a joint working group
(JWG) between TISPAN, 3GPP, and Parlay
groups. The later series of APIs, Parlay-X, provides basic Web service APIs for access to circuit-switched (CS), packet-switched (PS), and
IMS networks. Unlike other standards produced
within TISPAN or 3GPP, the Parlay and ParlayX APIs are provided royalty-free. As a result,
currently, these APIs are the most accessible
APIs that are available to third-party developers
within the standards bodies.
However, these APIs provide only very limited functionality. As an example, a developer
who wishes to use the Parlay-X call notification
API to intercept a call and display a picture
along with the ring signal at the dialed user has
no means of knowing whether the picture was
successfully received or not; there is no method
for a developer to receive the acknowledgment
from the dialed user. Therefore, although these
APIs handle session establishment reasonably
well, they are not designed to handle the data
model for the entire service; and therefore, they
fall far short of enabling innovative application
development.
The next section compares the existing open
API work in these standards bodies associated
with NGN with two consortia led by Google that
are attempting to create de facto standards for
open APIs within the social networking and
mobile networking arenas.
DE FACTO APIS AND THE
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The need for APIs that cover person-to-person
and person-to-service communication for the
wider development community has not gone
unnoticed. Two concepts were launched by
Google: OpenSocial and Android. Google Open
Social provides a common set of APIs for social
applications across multiple Web sites, whereas
Android attempts to offer the first complete,
open, and free mobile platform. The development of these APIs is intended to provide a de
facto standard for social networking and open
source APIs for mobile development. The development of consortia to solve such interoperability issues on behalf of developers indicates the
requirement for standardization of open APIs.
The stated goals of these open APIs are twofold: first, to provide developers with a powerful
tool kit that drives Google’s ad-driven strategy,
and second, to ensure all the applications can be
combined in a mash-up manner. This allows
developers to combine the user-centric programming API of OpenSocial with the session establishment APIs made available through Android.
The combination of these APIs enables developers to rapidly create services mash ups; for example, with little effort from developers, users can
receive notifications on their mobile phones
when others add them as friends on a social network.
The aim of these APIs also is to ensure that
anyone who can build a Web application can
build a social application. This extends the developer community for the Google platform quite
significantly in comparison to other available
APIs. The Google platform provides APIs for
free to developers and services for free to end
users; revenues are collected from advertisers.
Google OpenSocial APIs provide core functionality for creating user-centric applications
through APIs at the service-layer level. The core
functionality is closely associated with the data
of the end users, rather than with the session
establishment of APIs such as Parlay-X or the
existing JSRs. It also provides for data persistence without the use of a server. The core services of OpenSocial are:
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The stated goals of
these open APIs are
two-fold: first, to
provide developers
with a powerful tool
kit that drives
Google’s ad-driven
strategy, and second,
to ensure all the
applications can be
combined in a
mash-up manner.
People: Who
Friends: Relationships between people
Activities: Interactions between people
Persistence: State without a server
Android, on the other hand, is a platform for
a mobile device that provides APIs for application creation; with Android, the service mash-up
mentality is brought onto the actual device itself.
As an example, Android’s “View” API provides
extremely tight integration with the map and
browser applications — maps are actually
embedded into a developer’s application. As
with OpenSocial, there are several building
blocks, again all built around concepts of data:
Activity: What the user is doing
Intent Receiver: Reaction to external events
Service: long-lived code
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Third party developers
Developers with SLA
API within
“walled garden”
Open, free API
Basic standardized API
Extended nonstandardized API
Network functions
Figure 2. A split API offering, providing a base set of APIs for free for developers and a more detailed API for which they charge for access and provide
Service Level Agreements (SLA).
Content Provider: Allows application data to be
shared with other applications
The main difference in the APIs provided by
Android is that they are very simple to mash up
with other Google APIs that may be on its
servers or locally stored. This is due to the focus
of the APIs on data handling for the whole service, rather than on passing only limited session
establishment information.
It is clear that Google APIs “are poised to
support a significant ecosystem of application
developers” [2]. Therefore, the main issue for
NGN standardization is rather what Android
and OpenSocial are missing; they do not yet provide APIs for SIP, IMS, or any of the other
enablers on which member companies have
spent significant time, energy, and money.
Android, for example, uses XMPP to provide an
API for P2P services between Android devices,
which may force developers to use XMPP
instead of SIP or IMS.
Combining the OpenSocial APIs and the
Android APIs enables developers to create many
of the applications that have long been touted as
part of the NGN. It is clear that due to the size
of the consortia associated with these initiatives
that providing clear, simple APIs that allow
developers great flexibility are required and
demanded by the developer community. Therefore, NGN standardization also should respond
accordingly.
Therefore, Google has created APIs that are
specifically designed to handle user and service
data. Through these APIs, developers are able to
rapidly create and share data across applications;
Google APIs enable developers to pull data
from several sources and easily and cheaply
manage the new data model that emerges from
the combination of this data. There are no
requirements for massive back-end databases.
This is in contrast to the method of handling
user data defined within the context of the NGN.
There is a fundamental split between the subscription information and the end-user data utilized in a social network. In short, these APIs
are suitably and sufficiently interesting for the
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developer community but do not use the significant investments made within the traditional
standardization bodies. The next section discusses recommendations about what can be done to
protect the tremendous investments made in the
NGN platform and to reuse the work accomplished in the consortia such as OpenSocial or
Android to leverage the developer base that they
will develop.
THE FUTURE OF NGN OPEN API
STANDARDIZATION
The Internet world excels in the creation of
APIs that can be utilized rapidly by developers,
whereas traditional telecommunications standards bodies have not been so successful at creating APIs rapidly [8].
As the developments in Google OpenSocial,
Android, and so on, show, the Internet and
telecommunications industries finally are moving
closer together at the service level and as a
result, “the functional and service requirements
of domestic and commercial customers are
becoming increasingly incompatible with the
institutional divides” between the standardization bodies of the different sectors. This overlap
in work areas is likely to increase and as a result,
“the international [information and communications technology] ICT standardization system
must cope with the rapid technological changes
which are characteristic of both areas and which
are often inter-related” [8]. This section outlines
recommendations and highlights issues associated with the different paths that the standards
bodies can take in response to the requirement
for APIs on NGN networks.
The main difference between the IT view of
the world and the telecommunications view of
the world is how each views data. The standardization completed within the IT domain standards bodies primarily focuses on how to handle
user and service data: from its delivery using
HTML methods to service-to-service communication in a service oriented architecture (SOA).
IT service-layer standards take into account the
fact that there is an overall data model spanning
the network for each service; hence, the focus in
Google, eBay, and Amazon APIs on the handling of an end user’s data in relation to a particular service. Meanwhile, telecommunications
standardization has focused mainly on the establishment of sessions to support real-time communications. Although a basic user-service data
broker is available in the generic user profile
GUP (3GPP TS 29.240), bringing these two
worlds together is less trivial than it first appears.
Currently, user data and service data are stored
across the network; exposing this information in
a secure and appropriate manner is something
that a standardized open API in the NGN should
address.
The requirements for Web services in the
Internet world has been driven largely by business demands, for example, companies wishing
to integrate with the IT systems of other companies after a merger and acquisition or a joint
venture [9]. Enterprise customers now also build
and run reasonably large IT networks that they
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wish to combine with their voice networks.
Therefore, an important driver when creating a
standardized open API in the NGN is likely to
be including support for business-to-business
(B2B) interfaces; “Today, it is not only operators
that build networks, and that should also send a
very strong signal” [3]; these are as yet untapped
in terms of open APIs, and Google has clearly
stated it aims to address this in its OpenSocial
APIs.
The NGN platform, in conjunction with the
work outlined in Liberty Alliance for federated
identity management, is perfectly suited to provide a single, trusted source for social graphs in
social networks. APIs within the NGN should
provide the ability to manage such user data.
The APIs that the NGN platform provides
should “enable operators to leverage their key
assets, such as location, presence, reachability,
and quality-of-service capabilities” [7]. Operators
may wish to drive a split API offering, providing
a base set of APIs for free for developers and a
more detailed API for which they charge for
access and provide service level agreements
(SLAs), as illustrated in Fig. 2.
The APIs that are provided for the NGN
platform must be provided royalty-free to attract
developers to the platform. This is in direct conflict, for example, with the intellectual property
rights (IPR) rules of 3GPP and OMA. This is an
issue that must be addressed within each of
these bodies.
The OMA currently creates the mobile service enablers but has yet to produce APIs. The
OMA should work to create viable APIs for
each of its enablers. Currently, 3GPP CT5 does
API development and creation for telecom Web
services. As of October 2007, 3GPP CT5 has
agreed to align its APIs with work that is ongoing within the OMA. These APIs easily could be
reused within the scope of the OMA enablers.
The Parlay-X APIs, although in need of significant updating, reflect the best possibility for the
rapid creation of Web-based APIs. However,
Parlay-X APIs should be updated to reflect
more modern data models and to allow greater
control for the developers. The OMA, 3GPP
CT5, and other relevant industry standards bodies must put aside conflicts and work together to
create the most viable set of APIs possible to
secure a base of developers for the NGN platform.
The NGN standards bodies also must work
on the perception within the wider communications industries that NGN standards processes
are slow and prevent competition whereas de
facto Internet standards drive innovation and
competition between companies. Standardization
directly contributes to lowering costs for delivering services to end users.
The member companies of the standardization groups also should ensure that de facto
standards such as Google OpenSocial and
Android refer to existing architecture work completed within the scope of NGN standardization.
NGN standards groups should take a leaf from
Google’s book and provide APIs that are easy to
use, easy to integrate with other technologies,
and that are Web-based. NGN standards bodies
must do more than provide the framework for
the NGN; without open access APIs, the NGN
will not be an attractive platform on which to
build.
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Through combining
these open APIs with
a strategy of open
innovation, the
players within the
industry can create
an effective
two-pronged
CONCLUSIONS
approach to ensure
The link between the creation of open APIs and
the development of a large developer base for
software platforms is clear. NGN standardization
so far has neglected to provide high-quality,
Web-based APIs for developers to use on this
platform. The need for developers to have a
standardized interface has been indicated by the
establishment of two industry consortia under
Google — OpenSocial and Android. To protect
the investment members have made in NGN
standardization, open APIs must be developed
to ensure the success of NGN in providing innovative and rapid service creation. Through combining these open APIs with a strategy of open
innovation, the players within the industry can
create an effective two-pronged approach to
ensure a flourishing developer community for
the NGN.
a flourishing
developer
community for
the NGN.
REFERENCES
[1] ITU-T; http://www.itu.int/ITU-T
[2] D. Evans, A. Hagiu, and R. Schmalensee, Invisible
Engines, MIT Press, 2005.
[3] B. Nordström, Ericsson Business Rev. 2, 2007, pp. 58–60.
[4] T. Natsuno, i-mode Strategy, Wiley, 2003.
[5] H. Chesbrough, Open Business Models, Harvard Business School Press, 2005.
[6] J. Bessant and T. Venables, Eds., Creating Wealth from
Knowledge, Edward Elgar, 2008.
[7] A. Johnston et al., “Evolution of Service Delivery Platforms,” Ericsson white paper, Jan. 2007.
[8] OECD, “ICT Standardization in the New Global Context,” final rep., 1996.
[9] S. Weerawarana, Web Services Platform Architecture,
Prentice Hall, 2005.
ADDITIONAL READING
[1] 3GPP meeting reports; http://www.3gpp.org
BIOGRAPHY
CATHERINE E. A. MULLIGAN (ceam3@cam.ac.uk)
__________ received her
B.Sc. degree from the University of New South Wales, Australia, in 1999, her M.Phil. in engineering from the University of Cambridge in 2006, and is currently completing her
Ph.D. studies at the University of Cambridge. Her research
interests include innovation for mobile broadband applications, the role of core network evolution in enabling innovative applications, and the role of developer communities
in the emerging industrial structure of the communications
industries. Between 1999 and 2005, she worked at a
telecommunications company in Sweden.
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SERIES EDITORIAL
Wai Chen
I
Luca Delgrossi
EEE Communications Magazine started a new series on
automotive networking in 2008, with the first issue published in May 2008. In this third issue of the Automotive
Networking Series, we are pleased to present a column
and four articles that address important topics related to
the standards and technologies of vehicular networking.
Significant efforts have been underway by governments,
transportation authorities, automobile manufacturers, and
the academic community to accelerate the development of
an intelligent transportation system (ITS) for safe, efficient, and convenient driving. Many of the research efforts
have been devoted to effectively integrating wireless communications and computing technologies into vehicular
and transportation systems. For example, there has been
much recent research work on many relevant challenges,
including characterization of vehicular communication
channels and development of wireless system technologies;
design of protocols for vehicle-to-vehicle (V2V), vehicleto-roadside (V2R), or vehicle-to-infrastructure (V2I) networking that adapt to changes of roadway conditions to
provide fast, reliable communications; simulation methodologies and tools to validate designs in realistic roadway
scenarios; standards for communications; and technologies
to achieve security and privacy, among others. To date,
this Series has published articles that address several of
these challenges. The articles in the current issue address
standards efforts in the European Union, an overview of
IEEE WAVE, VANET simulation methodology, vehicle
traffic modeling, and V2I communications.
Wireless communications for ITS is an enabling technology to improve driving safety, reduce traffic congestion,
and support information services to vehicles. However, one
key to realizing such ITS benefits relies on establishing
standards that govern communications among networking
peers such as vehicles, roadside units, or wireless infrastructure. In the European Union there is an ongoing
effort to encapsulate the extensive ITS work there into a
European ITS communication architecture, with participation of key projects and organizations such as COOPERS,
CVIS, Safespot, SeVeCOM, ETSI, C2C-CC, IETF, and
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Timo Kosch
Tadao Saito
ISO. The column, “European Communication Architecture for Cooperative Intelligent Transportation” by T.
Kosch et al., provides an overview of this ongoing EU
effort by focusing on the technical developments in Europe
and their convergence toward a set of European standards.
The authors describe the current state of the EU standards
activities, potential application scenarios, use cases, and
communication architecture.
To facilitate the provision of wireless access in vehicular
environments, the IEEE has devoted efforts to establish a
system architecture known as WAVE. The second article,
“WAVE — Wireless Access in Vehicular Environments: A
Tutorial” by G. Acosta-Marum et al., gives an overview of
the associated standards of IEEE 802.11p and IEEE
1609.1-4. The authors first give a general description of the
WAVE architecture, and then describe its main components and their functions.
Evaluation and validation of vehicular ad hoc network
(VANET) protocols are typically accomplished via computer simulations since realistic field tests can be costly.
Simulation methodologies and tools to evaluate VANET
protocols and applications in realistic vehicular traffic conditions have received much research attention lately. The
third article, “VGSim: An Integrated Networking and
Microscopic Vehicular Mobility Simulation Platform” by
B. Liu et al., addresses the use of simulation as a primary
tool for VANET study. The authors first provide an
overview of the current state of the art of VANET simulation methodologies and tools. They then describe the
design of their VGSim platform and its support of vehicular mobility models and applications.
Vehicular traffic mobility in urban areas exhibits more
complex patterns (e.g., turns, stops, signal controls at intersections) than that on highways. Modeling of global traffic
patterns in complex urban road networks is challenging,
but it can provide useful insights into the design and evaluation of VANETs. For example, recent studies have shown
that vehicular mobility models can have significant impacts
on the outcome of VANET simulations or the network
connectivity behavior of VANETs. The fourth article,
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SERIES EDITORIAL
“Modeling Urban Traffic: A Cellular Automata Approach”
by O. K. Tonguz et al., focuses on the construction of
urban vehicular traffic mobility models. The authors first
provide an overview of existing traffic mobility models, and
then propose a new cellular automata-based model that
captures a realistic intersection control mechanism and
provide rules for realistic motion of turning vehicles. The
authors also show the impacts of intersection control
mechanisms on intervehicle space distribution and traffic
dynamics.
Users increasingly demand Internet access in automotive environments such as suburban trains, city buses, or
subways in order to make productive use of the commuting
time spent in public transportation systems. Traditional IP
mobility mechanisms rely on the support of both the moving terminals and the network; while a recent trend is to
enable network-based mobility of IP devices with only the
support from the network (i.e., support mobility without
the involvement of the moving terminals). The fifth article,
“NEMO-Enabled Localized Mobility Support for Internet
Access in Automotive Scenarios” by I. Soto et al., provides
an overview of major existing approaches that are relevant
to Internet access in vehicular environments. The authors
first give an overview of relevant mechanisms developed in
the IETF, including network-based mobility support (e.g.,
Proxy Mobile IPv6) and mobile network support (e.g.,
NEMO Basic Support) for transparent Internet access
from vehicles. They then describe an architecture that supports a mobile network (network that moves, NEMO)
without need for the moving terminals’ involvement.
We thank all contributors who submitted manuscripts
for this series, as well as all the reviewers who helped with
thoughtful and timely reviews. We thank Dr. Nim Cheung,
Editor-in-Chief, for his support, guidance, and suggestions
throughout the process of putting together this issue. We
also thank the IEEE publication staff, particularly Ms. Jennifer Porcello, for their assistance and diligence in preparing the issue for publication.
BIOGRAPHIES
WAI CHEN (wchen@research.telcordia.com)
________________ received his B.S.E.E. degree from
Zhejiang University; and M.S.E.E., M.Phil., and Ph.D. degrees from
Columbia University, New York. Currently he is with Applied Research, Telcordia Technologies Inc. (formerly known as Bellcore), where he is a chief
scientist and director of Ubiquitous Networking and Services Research. He
has been leading a vehicular communications research program in collaboration with a major automaker since 2000 on automotive networking technologies for vehicle safety and information applications. He has also been
the principal investigator of several government-funded projects on
advanced networking technologies research. He served as a Guest Editor
for the Special Issue on Intervehicular Communication (IVC) for IEEE Wireless Communications (2006), as an IEEE Distinguished Lecturer (2004–2006),
Co-Chair of the Vehicle-to-Vehicle Communications (V2VCOM) Workshop
collocated with the IEEE Intelligent Vehicles Symposium, and Co-Chair of
the IEEE Automotive Networking and Applications (AutoNet) Workshop collocated with IEEE GLOBECOM. His current research interests are vehicle
communications and ITS applications, and mobile wireless communications
systems.
LUCA DELGROSSI is manager of the Vehicle-Centric Communications Group at
Mercedes-Benz Research & Development North America Inc., Palo Alto, California. He started as a researcher at the International Computer Science
Institute (ICSI) of the University of California at Berkeley and received his
Ph.D. in computer science from the Technical University of Berlin, Germany.
He served for many years as professor and associate director of the Centre
for Research on the Applications of Telematics to Organizations and Society
(CRATOS) of the Catholic University at Milan, Italy, where he helped create
and manage the Masters in Network Economy (MiNE) program. In the area
of vehicle safety communications, he coordinated the Dedicated Short
Range Communications (DSRC) Radio and On-Board Equipment work
orders to produce the DSRC specifications and build the first prototype
DSRC equipment as part of the Vehicle Infrastructure Integration (VII) initiative of the U.S. Department of Transportation. The Mercedes-Benz team in
Palo Alto is a recognized leader in the research and development of vehicle-to-infrastructure as well as vehicle-to-vehicle communications safety systems.
T IMO K OSCH works as a team manager for BMW Group Research and
Technology, where he is responsible for projects on Car2X, including
such topics as cooperative systems for active safety and automotive IT
security. He has been active in a number of national and international
research programs, and serves as coordinator for the European project
COMeSafety, co-financed by the European Commission. For more than
three years, until recently, he chaired the Architecture working group
and was a member of the Technical Committee of the Car-to-Car Communication Consortium. He studied computer science and economics at
Darmstadt University of Technology and the University of British
Columbia in Vancouver with scholarships from the German National
Merit Foundation and the German Academic Exchange Service. He
received his Ph.D. from the Computer Science Faculty of the Munich University of Technology.
TADAO SAITO [LF] received a Ph.D. degree in electronics from the University
of Tokyo in 1968. Since then he has been a lecturer, an associate professor,
and a professor at the University of Tokyo, where he is now a professor
emeritus. Since April 2001 he is chief scientist and CTO of Toyota InfoTechnology Center, where he studies future ubiquitous information services
around automobiles. He has worked in a variety of subjects related to digital communications and computer networks. His research includes a variety
of communications networks and their social applications such as ITS.
Included in his past study, in the 1970s he was a member of the design
group of the Tokyo Metropolitan Area Traffic Signal Control System
designed to control 7000 intersections under the Tokyo Police Authority.
Now he is chairman of the Ubiquitous Networking Forum of Japan, working on a future vision of the information society. He is also chairman of the
Next Generation IP Network Promotion Forum of Japan. He has written two
books on electronic circuitry, four books on computers, and two books on
digital communication and multimedia. From 1998 to 2002 he was chairman of the Telecommunication Business Committee of the Telecommunication Council of the Japanese government and contributed to regulatory
policy of telecommunication business for broadband network deployment
in Japan. He is also the Japanese representative to the International Federation of Information Processing General Assembly and Technical Committee
6 (Communication System). He is an honorary member and fellow of the
IEICE of Japan.
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AUTOMOTIVE NETWORKING SERIES
Communication Architecture for
Cooperative Systems in Europe
Timo Kosch, Ilse Kulp, Marc Bechler, Markus Strassberger, and Benjamin Weyl, BMW Group
Robert Lasowski, Cirquent
ABSTRACT
Wireless communications for intelligent
transportation systems promise to be a key technology for avoiding the traffic nightmares of
today — accidents and traffic jams. But there is
one major challenge to be overcome before such
a cooperative system can be put into place: standardization. This article provides an overview of
the technical developments in Europe and their
convergence toward a set of European standards. We address the current state of the standardization activities and the potential scenarios
and use cases, and we describe the fundamental
concepts of a European communication architecture for cooperative systems.
INTRODUCTION
1
With liaisons to all relevant stakeholders, the provision of information and
preparation of strategic
guidelines, COMeSafety
directly supports the European eSafety Forum on
the items of cooperative
systems for road safety
and traffic efficiency.
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In the future, Europeans who use the road will
benefit from improved safety, reduced traffic
congestion, and more environmentally friendly
driving, all enabled by the deployment of cooperative systems. The key to achieving these benefits lies in a common and standardized means
of communication between the various components of such systems, whether these components are located in vehicles or at the roadside
or in the back-end infrastructure.
The vast work on applications and technologies, protocols, and security mechanisms in current European research shall fit into one overall
architectural framework. To achieve this, a
group of experts (called the Architecture Task
Force) moderated by the European project
COMeSafety1 [1] consolidated such a framework
and fostered its adoption. Major European projects on related issues have been participating,
especially the following integrated projects:
FRAME [2], COOPERative networks for intelligent road Safety (COOPERS) [3], Cooperative
Vehicle-Infrastructure System (CVIS) [4], and
Safespot [5], as well as the specific targeted
research project (STREP) called Secure Vehicular Communication (SeVeCom) [6]. To achieve
wide acceptance and prepare European standardization at the European Telecommunications Standards Institute (ETSI) [7], the
0163-6804/09/$25.00 © 2009 IEEE
Architecture Task Force worked in close cooperation with the Car2Car Communication Consortium (C2C CC) [8] and relevant standardization
bodies such as the Internet Engineering Task
Force (IETF) [9] and the International Standards Organization (ISO) [10]. In essence,
results from European research projects have
provided the basis for consolidation. Recommendations were derived for further consideration in C2C CC. Out of the consortium, work
items are proposed for standardization at ETSI.
The whole process is depicted in Fig. 1.
In October 2008, the first public version of a
document describing the baseline for a European intelligent transportation system (ITS)
communication architecture for cooperative systems was published by COMeSafety entitled
“The European ITS Communication Architecture.” This article provides an overview of the
basics of this architecture, which also was adopted by new research projects like PREparation
for DRIVing implementation and Evaluation
(PRE-DRIVE C2X) [11] for further development, and by ETSI for European standardization.
We introduce the basic scenario and user
needs in the next section. We then propose different aspects of the ITS communication architecture. The final section concludes this article
and gives an outlook for future activities.
SCENARIOS AND USER NEEDS
Three basic scenarios are supported by the
framework, comprising the following application
classes:
• Traffic safety
• Traffic efficiency
• Value-added services (e.g., infotainment,
business applications)
Traffic safety applications support services
such as lane departure warnings, speed management, headway management, ghost driver management, hazard detection, and several other
similar services. Traffic efficiency applications
support services such as urban traffic management, lane management, traffic flow optimization, and priority for selected vehicle types (e.g.,
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Strategy
Work items
CAR 2 CAR Working Groups
• WG Application
• WG Architecture
• WG Network
• WG PHY/MAC
• WG Security
• WG Standardization
• WG Simulation
Tasks:
• Frequency/allocation
• Propose work items
• Prepare white papers,
documents
• Revise CAR 2 CAR CC documents
• Comment documents
• Build-up Car 2 CAR CC
demonstrators
• Draft business models
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Harmonization
Recommendation
Strategy
Requirements
Consolidation
Expert group
Collaboration
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Architecture task force
Communications
TC ITS Working Groups
• WG 1 Application Requirements
and Services
• WG 2 Architecture and Cross
Layer Issues
• WG 3 Transport and Network
• WG 4 Media and Media Related
Issues
• WG 5 Security
Tasks:
• Propose ETSI TC ITS work items
• Prepare ETSI TC ITS documents
• TR - technical recommendations
• TS - technical specifications
• Revise ETSI TC ITS documents
Figure 1. European consolidation, harmonization, and standardization of cooperative its systems.
buses, emergency vehicles). Applications providing value-added services include pre-trip and ontrip journey planning, travel information, and
location-based services.
There are hundreds of different use cases
considered and developed within the different
projects. They all can be mapped onto one of
these application classes.
A number of graphical illustrations provide
an overview of the system concept: connecting
vehicles, roadside (traffic) infrastructure, and
central (traffic) infrastructure to improve safety
and traffic efficiency on European roads. Figure
2 is a sketch from ETSI [12] that shows the different deployment scenarios.
ITS COMMUNICATION
ARCHITECTURE
From the viewpoint of the communicating entities, the ITS communication architecture comprises four main entities: vehicles, roadside
equipment, central equipment, and personal
devices (Fig. 3). Each of the four entities contains an ITS station and usually a gateway connecting the ITS station to legacy systems (vehicle
gateway, roadside gateway, and central gateway,
respectively). An ITS station comprises a number of ITS-specific functions and a set of devices
implementing these functions.
Depending on the deployment scenario, the
four entities can be composed arbitrarily to form
a cooperative ITS. The entities can communicate
with each other using several communication
networks. Communication can be performed
either directly within the same communication
network or indirectly across several communication networks. Hence, ITS stations basically provide communication capabilities, as well as the
implementation of the different use cases.
A vehicle is equipped with communication
Satellite
communications
Terrestrial
broadcast
Mobile
Intermodal
communications
Navigation
MAN
Vehicle-to-vehicle Safety systems
Traffic signs
Passenger
information
WLAN
Travel
assistance
Trip
planning
Adaptive
cruise control
Fleet management
Toll collection
©ETSI 2008
Figure 2. ETSI TC ITS scenario overview [12].
hardware for communication with other vehicles
or with roadside infrastructure. This hardware is
connected to the vehicle onboard network to
collect data within the vehicle. In this way, vehicle data can be exchanged between vehicles. The
communication hardware also can support wireless Internet access in order to communicate
with back-end services running in a central entity. Hence, information from the vehicle can be
sent immediately to the central system. The
functions of a vehicle station in one implementation can be split onto several physically separated nodes communicating over a local area
network (LAN) such as Ethernet. The communication function would be supported by a communication node (a mobile router) in charge of
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Central ITS station
Central
gateway
Applications
Border
router
Central
host
Ethernet
Networking
& Transport
Access
Technologies
Ethernet
CAN bus
Networking
& Transport
Access
Technologies
IPv6
Ethernet
Central system
Communication
network
Vehicle
Roadside station
Vehicle Station
VMS
VMS
Vehicle
host
Facilities
Security
Access
Technologies
Security
Mangement
Facilities
Networking
& Transport
Mangement
Networking
& Transport
Security
Mangement
Applications
Facilities
Access
Technologies
Mobile
router
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Central
Mobile
Mangement
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Security
Communications
5.9
Vehicle
gateway
Roadside
gateway
Roadside
host
Access
router
Border
router
Ethernet
Ctrl
Ctrl
CAN bus
5.9GHz
Ethernet
Networking
& Transport
Access
Technologies
Ethernet
Security
Facilities
Networking
& Transport
Access
Technologies
Ethernet
IPv6
Security
Access
Technologies
Mangement
Access
Technologies
Networking
& Transport
Mangement
ECU
Facilities
Networking
& Transport
Security
Access
Technologies
ECU
Security
Security
Applications
Facilities
Networking
& Transport
Mangement
Access
Technologies
Security
Networking
& Transport
Mangement
Facilities
Mangement
Access
Technologies
Mangement
Networking
& Transport
Security
Mangement
Applications
SENS
SENS
Figure 3. European ITS communication architecture [13].
Applications
Networking
and transport
Security
Management
Facilities
Access
technologies
Figure 4. ITS communication protocol architecture [13].
communication for other vehicles or roadside
stations, whereas applications can be supported
by a number of other dedicated nodes (vehicle
hosts). In another implementation instance, a
unique node can support both the communication functions and the applications. The decision
of how to implement the required set of func-
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tions of an ITS station is left to the stakeholders
who deploy this ITS communication architecture.
Roadside infrastructure components include
variable message signs (VMSs) or traffic lights,
which also are equipped with communication
hardware. In this way, the roadside infrastructure
components can communicate with vehicles, for
example, to send information to the vehicles or
to act as relay stations for (multihop) communication between vehicles. Additionally, a roadside
infrastructure component can be connected to
the Internet. Hence, a roadside infrastructure
component can communicate with central components and can forward information received
from vehicles to central components.
Typically, the central entity is an organizational entity, where centrally managed applications and services are operated. For example,
this can be a traffic management center controlling roadside infrastructure or an advertisement
company that distributes location-based advertisements (through the roadside components) to
the vehicles.
Finally, a personal component typically represents a mobile consumer device, such as a mobile
phone or navigation device, which also can provide numerous ITS applications. Typically, these
devices are assigned to a person and use appropriate communication hardware. The devices
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also can support cooperative ITS applications
based on communications with other road users
or roadside infrastructure.
From a communication perspective, an ITS
station is based on the reference protocol stack
depicted in Fig. 4. This protocol stack consists of
four horizontal layers: access technologies, networking and transport, facilities, and applications. In addition, it is flanked by a management
layer and a security layer. In the following, we
will detail several aspects of this communication
protocol architecture.
Application
facilities
ITS facilities
ITS and IP facilities
IP facilities
Local dynamic
mapsupport
Positioning and
time
SOA application
protocol support
IEEE
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HMI support
Service
management
support
Information
facilities
Location
referencing
Station
capabilities and
monitoring
Relevance checker
Vehicle data
provider
Communication
facilities
Messaging
support
Service
advertisement
support
Addressing
support
SOA session
support
Traffic
management
message support
Access
technology
selector
Figure 5. ITS reference architecture: facilities [14].
adapt its behavior to the system configuration.
The system is developed continuously and
can be configured with respect to the preferences and needs of an individual driver. Therefore, it must be possible to update or install
applications. Additionally, the update and installation process must be performed without producing an instable system or causing any risks
for the driver. Therefore, service management
support is responsible for safe and stable operation of the ITS station. Another information
facility is the relevance checker. This module
acts as an information filter, calculating the relevance of each received message. If a received
message is considered relevant in a certain situation, the applications can decide how to present
it to the driver or how to use it to control driver
assistance or vehicle systems. However, the relevance checker is not responsible for filtering and
prioritizing messages.
The SOA-based modules support only the IPbased applications. They are responsible for
common network services that are used by business and entertainment applications, for example, Web services and related session protocols.
The most important functionalities here are connection establishment, unexpected connection
loss handling, and seamless changing of access
technologies.
Messaging support is responsible for the generation, extraction, and management of the following two important ITS-based messages:
• Cooperative awareness message (CAM),
providing the key heartbeat information of
the ITS station
• Decentralized environment notification
message (DENM), providing information
about existing hazards in a defined area.
The messaging support is further responsible
for the caching of DENMs. In contrast, the traf-
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Facilities
FACILITIES
Because ITS applications are a fundamental part
of cooperative ITS, it is essential to provide functionality for rapid application development. Furthermore, it is important to ensure that each
application running on the same ITS station is
using the same data and information to guarantee a consistent quality of service. To facilitate
rapid development, standardized access to information, data, and common functionalities is
required. Therefore, a middleware and repository
concept is introduced, called the facilities layer.
The facilities layer is integrated between the
application layer and the network and transport
layer. The facilities layer features service access
points to the management layer and the security
layer.
This layer provides facilities for applications,
information, and communication. The services
can be accessed by ITS-based applications, as
well as Internet Protocol (IP)-based applications.
However, not every application type has permission to access each service, for example, ITSbased applications do not have access to
service-oriented architecture (SOA) facilities,
whereas IP-based applications must not utilize
the relevance checker (Fig. 5).
To avoid a discrepancy between applications
regarding the correctness of data, the facilities
layer offers consolidated, up-to-date, and consistent information, for example, for position, time,
speed, and acceleration. This data can be provided by a global navigation satellite system (GNSS)
or optionally by a vehicle data provider module
for more accurate data. The vehicle provides an
application programming interface (API) to the
vehicle information, for example, through a controller area network (CAN) bus. This enables
the development of applications without having
any proprietary knowledge of the specific vehicle
brand and model. The information is encapsulated in the facilities and is offered to the applications in a standardized way. To provide
consolidated information about the environment
of an ITS station, the local dynamic map (LDM)
provides data models to represent both dynamic
information and static information. An LDM is
mandatory for all vehicle ITS stations. The facilities layer also enables standardized access to the
configuration of the ITS station. Modules like
human-machine interface (HMI) support or station capabilities and monitoring contain information about station-specific HMI, the type of
station, and the access technologies. In addition,
it provides information about the identity of the
ITS station. Utilizing this information, each ITS
application can configure itself dynamically and
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ITS transport
ITS
network
Georouting
TCP, UDP
Other
protocols
IPv6 +
mobility
extensions
Figure 6. ITS reference architecture: network and transport [13].
fic management message provides similar functionality for traffic efficiency messages like traffic information messages (e.g., Transport
Protocol Experts Group [TPEG]). In combination with addressing support, messages can be
sent by a defined dissemination strategy, for
example, broadcast, geocast, or unicast. To handle different kinds of communication technologies in a flexible way, the access technology
selector provides the contingency to choose an
appropriate radio technology for message transmission.
With the help of the facilities layer, the ITS
provides transparent APIs containing frequently
used information and functionality. Hence, it
accelerates the development of applications by
also providing the desired information quality,
independent of different station types.
NETWORK AND TRANSPORT LAYER
The network and transport layer in the reference
protocol stack of ITS stations provides services
for the layers above it and utilizes the capabilities of the underlying access technologies. The
objective of the network and transport layer is
the transport of data between source and destination ITS stations; either directly or multihop
through intermediate ITS stations.
At the network and transport layer, there are
three scenarios:
•Communication among ITS vehicle stations
in an ITS ad hoc network — This can be either
communication from an ITS vehicle station to
other ITS vehicle stations (vehicle-to-vehicle),
from an ITS roadside station to ITS vehicle stations (roadside-to-vehicle), or from an ITS vehicle station to ITS roadside stations
(vehicle-to-roadside). The communication types
can be concatenated: a typical example would be
an ITS vehicle station communicating with
another ITS vehicle station through an ITS roadside station or even through the ITS roadside
infrastructure network.
•Communication between ITS vehicle stations and other nodes through the ITS roadside
infrastructure domain — This scenario covers
communication among ITS stations and different
types of nodes in the communication infrastructure, including IP nodes in the Internet,
nodes in the ITS application service system
(such as the traffic management center and
back-end servers), or nodes in the ITS operational support system. The scenario requires that
ITS roadside stations have access to the Internet
domain. Due to the nature of communication in
the ad hoc network, the ITS vehicle stations
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might have intermittent connectivity to ITS
roadside stations and consequently, non-permanent connectivity to the Internet domain with
the attached service domains.
•Communication between ITS stations and
other nodes through a generic access domain —
The network scenario is the same as the previous scenario, except that the generic access
domain — typically a second generation/third
generation (2G/3G) cellular network — replaces
the ITS roadside infrastructure domain. The
generic access and Internet domain enable connectivity between ITS stations and other nodes,
as well transparent transport of IP packets from
and to the ITS stations. In contrast to the intermittent connectivity by an ITS roadside infrastructure network, the architecture presumes
that the generic access domain provides (almost)
full spatial coverage and permanent connectivity
to ITS stations.
The three network scenarios provide support
for typical use cases for safety, traffic efficiency,
infotainment, and business applications. From a
communications protocol viewpoint, the network
and transport layer is divided into two parts:
• ITS-specific network and transport protocols
• IP-based network and transport protocols
(Fig. 6).
ITS-specific protocols on the network and
transport layer support self-organized communication among ITS stations without coordination
by a communication infrastructure. If connectivity to an ITS roadside infrastructure network is
available, the protocols may not preclude assistance and coordination by infrastructure nodes.
For safety-related use cases having stringent
requirements on the latency of message delivery,
protocols support communication without a priori signaling. Therefore, network nodes have at
least one unique network address, which can be
based on the identity of a node or geographical
position. The protocols are capable of addressing destinations based on geographical regions
or areas. The address configuration of ITS stations is based on automatic address configuration. The routing of packets incorporates
priorities and is supported efficiently for various
connection types, including point-to-point, pointto-multipoint, geographical anycast, and geographical broadcast. The protocols support
security aspects, which, in particular, include
data integrity, authentication, and non-repudiation. They also provide means to protect privacy,
that is, they provide confidentiality for personal
data such as ID and location of an ITS station.
The generic message structure for messages
exchanged directly between vehicles in the ad
hoc part of the network is shown in Fig. 7. The
relevant messages are CAM and DENM, which
are described in the section on the facilities
layer.
In addition to the functional aspects, ITS-specific transport and network protocols must meet
a number of performance-related requirements,
such as low-latency communications; reliable
communications, with the highest reliability for
safety messages; low overhead for signaling,
routing, and packet forwarding; fairness among
ITS stations with respect to bandwidth usage,
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ACCESS TECHNOLOGIES
Both wired and wireless access technologies
are supported for station-external and stationinternal use. However, the architecture so far
only describes wireless access technologies, that
is, different types of radio systems. Currently,
the following wireless systems are considered:
• Short-range and ad hoc systems — This
includes European Committee for Standardization dedicated short range communications (CEN DSRC), European 5.9-GHz
ITS, wireless LAN (WLAN), and Infrared.
• Cellular systems — This includes WiFi,
worldwide interoperability for microwave
access (WiMAX), global system for mobile
communications/general packet radio service (GSM/GPRS), and the universal
mobile telecommunications system
(UMTS).
• Digital broadcast systems — This includes
digital audio broadcasting (DAB) and digital multimedia broadcasting (DMB), digital
video broadcasting-terrestrial (DVB-T) and
DVB-handheld (DVB-H), and global positioning system (GPS).
Wired technologies are used mainly as station-internal interfaces, whereas wireless technologies are used primarily as station-external
Net header :
Node ID
Node type
Sequence number
Time stamp
Node long
Node lat
F
Sequence of
Node elevation
Pos confidence
Node speed
Speed confidence
Heading
Hooding confidence
Safety PDU
is a mandatory
field for CAM
Forwarder
message
V.A. Services
PDU #n
V.A. Services
PDU #1
Efficiency
PDU
Safety
PDU
Transport
header
Security
Forwarding
Protocol data unit
The darker
elements are optional
Figure 7. Generic message structure [13].
interfaces. The purpose of the access technologies layer is to handle the interfaces to the different communication technologies. An access
technology typically contains only the two lowest
layers in the ISO open-systems interconnection
(OSI) stack, namely, the physical (PHY) and the
data link (DL) layers. However, for some of the
access technologies, for example, Bluetooth, the
entire communication protocol stack is used.
In the same way, the word “traffic” has an
ambiguous meaning in the context of vehicular
communication (i.e., it can relate either to data
traffic or vehicle traffic), and the word “infrastructure” can refer either to communications
infrastructure (e.g., access points and base stations used by a communications technology) or
road infrastructure (e.g., road signs or traffic
management centers). The former is most important in the lower protocol layers, whereas the
latter is more important in the application layer.
In the non-ITS context, communications infrastructure is referred to either as access points
(typically, in data communications networks such
as WLANs) or base stations (typically, in
telecommunications networks such as GSM). In
a network containing access points or base stations, all communication must take place through
the access point or base station. This implies
that no peer-to-peer or direct vehicle-to-vehicle
communication would be possible and that consequently, the minimum delay/latency is longer.
A network without access points or base stations
is referred to as an ad hoc system. Communication in an ad hoc system can take place using
peer-to-peer communications or master-worker
communications.
Typically, each radio system is developed for
a particular purpose and as such, it is best if
used for that purpose. Data communication networks such as WiFi are developed for high-rate
Internet applications and therefore, usually provide high rate and high reliability but no realtime support. Telecommunications networks
such as GSM are developed for voice applications and consequently, provide low-delay, realtime support at the expense of reduced
reliability. Note, however, that the reduced reliability can be tolerated for voice applications,
whereas this is not the case for most applications
carrying data traffic. Other radio systems such as
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considering the type of messages; robustness
against security attacks and malfunction; and the
capability of working in scenarios with different
densities of ITS stations.
To support the second scenario, we consider
IPv6 as the predominant network protocol on
the infrastructure side. Depending on the realization of the use cases, in addition, IPv6 can
incorporate mobility extensions. On top of the
IP-based network protocols, the Internet transport protocols Transmission Control Protocol
(TCP) and User Datagram Protocol (UDP) are
used to provide end-to-end connectivity for the
IP-based applications (or IP-based facilities).
For the third scenario, the functionality and
performance that can be provided by the network and transport layer depends on the capabilities of the generic access network. Currently,
we assume that the generic access domain provides transparent transport of IPv6 packets.
Many reasons have driven the selection of IPv6
over IPv4:
• The number of subsystem components that
will be supported: the ultimate objective is
to support all vehicles and personal devices,
that is, 200 million vehicles in Europe plus
all personal ITS stations, namely, the
mobile devices (possibly more than one per
citizen), which cannot be supported by the
address space of IPv4.
• IPv6 enhanced features: IPv6 provides new
features such as network mobility, autoconfiguration, quality of service, multiple
interface management, and so on that are
key features to meet ITS requirements.
• European recommendations: following a
study of the impact of IPv6 on vertical sectors, the European Commission published
an IPv6 action plan in May 2008, which
established 2010 as a target date to deploy
IPv6 on a wide-scale in Europe.
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TPC range 30 dB
Max. TP e.i.r.p.:
e.i.r.p. limit (dBm/MHz)
Protection
feasible
10
0
-10
ECC rec.
-20
-30
-40
ECC decision
EC decision
Non-safety ITS road safety
application
ITS
application
Future
extension
-50
-60
Mitigation
required
Justification for
30–50 NHz
-70
5810 5820 5830 5840 5850 5860 5870 5880 5890 5900 5910 5920 5930
Frequency (MHz)
Figure 8. European frequency regulation for 5.9 GHz [1].
CEN DSRC are even more application-specific
and thus if used in the intended context, they
provide high performance. Few, if any, current
radio systems can support high reliability, low
latency/delay, real-time communications because
typically, reliability is increased with increased
delay (e.g., using retransmissions).
For time-critical, safety-related applications,
therefore, a dedicated access technology was
developed within IEEE as 802.11p. A dedicated
frequency is required for this technology to provide the mandatory reliability and quality of service. COMeSafety, together with C2C CC,
fostered the assignment of such a protected frequency band in Europe, which led to the EuroConference
of
Postal
and
pean
Telecommunications Administrations (CEPT)
and European Commission decisions on the
allocation of 30 MHz of frequency in the 5.9GHz band. The Radio Spectrum Committee of
the EC developed the commission decision on
the harmonized use of radio spectrum in the
5875-5905-MHz frequency band for safety-related applications of ITS, which finally was
approved and published. The European profile
of IEEE802.11p now is being developed, with
the core safety part working within this 30-MHz
band and referred to as ITS-G5A. This process
has been driven by ETSI and CEPT.
Figure 8 shows the result of the allocation,
also showing 20 MHz of spectrum for possible
future extension of the 30 MHz for ITS road
safety and an unprotected part of another 20
MHz for non-safety ITS applications.
SECURITY
ITS communication enables a broad range of
safety applications. Although this functionality
inspires a new era of safety in transportation,
new security requirements must be considered to
prevent attacks on these systems.
Attacks can be manifold: illegally forced malfunctioning of safety critical in-vehicular components, as well as the illegal influence of traffic
provoked by means of fake messages are just
two likely possibilities. Some potential attacks on
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the ITS use cases are:
• Extraction/modification of secret material
• Tampering with the vehicle’s ITS station
• Network jamming
• Alteration attack
• Fake message injection
• Sybil attack
• Privacy violation
23 dBm/MHz,
but not more
than 33 dBm
20
A
Security Baseline — Because a vehicle
equipped with an ITS station periodically geobroadcasts information like its position, the real
identity of the vehicle will be concealed to protect its privacy against both malicious and casual
observation or tracking. This means that permanent identifiers and addresses must not be
encrypted over the air. In contrast, in all layers
— from access technologies over network and
transport and facilities to applications — in-vehicle systems will use temporarily assigned identifiers. Fixed identifiers should be used only in the
occasional situation where mutual system
authentication is required, for example, when
obtaining a new set of temporary identifiers. The
real identity is not to be revealed over the air,
but must be concealed accordingly. To ensure
trust in messages, they must be signed. Signing
of messages must occur with dynamically
assigned, temporary pseudonyms. Currently, it is
under investigation how frequently pseudonyms
must be updated and what the technical mechanisms will be for this procedure.
Moreover, it is yet to be decided which crypto technology to use for these pseudonym signatures. For this choice, a number of factors
must be balanced, for example, security level,
size of signature and bandwidth constraints,
processing time, and real-time requirements of
safety applications. Currently, the Revist
Shamir Adelman (RSA) algorithm and elliptic
curve cryptography (ECC) are candidates under
investigation [6].
Security Abstraction — Information Technology (IT) security is a cross-layer component and
must provide respective security services across
all layers (Fig. 9). The security services of the
architecture comprise:
• Firewalls, for example, packet or content filter.
• Intrusion management mechanisms, namely,
intrusion detection and intrusion response.
• Authentication services.
• Authorization services including policy decision and policy enforcement.
• Privacy services including creating
pseudonyms for digital identities and providing anonymity for data.
• Key management enabling the establishment of trust relations among entities (e.g.,
using certificates).
• Trust services such as trust establishment
and the provisioning of information about
the amount of trust for specific information.
• Hardware security services, for example,
secure storage of security credentials.
The security services enable the following
features:
• The establishment of secure communication
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The management
SM-SAP
Networking
and transport
SN-SAP
Security
Management
Facilities
e.g. e.g.
e.g.
e.g.
GPS BlueTooth 2G/3G/... Ethernet
SI-SAP
Access technologies
e.g.
e.g.
5.9GHz WiFi
to ally applications,
Security information base
(trust, identy, privacy, CryptoKey and certificate management
Security
Applications
Firewall and intrusion management
SF-SAP
ITS station reference architecture
Authentication, authorization, confidentiality, profile management
SA-SAP
layer is responsible
networks, and
interfaces in a specific implementation.
This implementation
can range from a
simple standalone
unit in a vehicle
(vehicle station) to a
complex router/host
interaction in a large
roadside network.
Hardware security
module (HSM)
Figure 9. Security layer [13].
channels, for example, between vehicle and
the operation support system.
• Privacy preserving ITS communication, for
example, preventing location tracking or
preventing illegal access to private information.
• Unauthorized access to services within the
infrastructure or the vehicle.
• Detection of malicious behavior and triggering of respective security countermeasures
to contain a security attack (intrusion
response).
• Resistance against software attack and tamper. The security service can provide a
secure area for storing security credentials
and algorithms processing security information.
The abstract description of the security services allows for a future-proof architecture. Each
security service can be mapped to a specific
security implementation, implementing an
abstract security interface. Then, the security
implementation can be flexibly changed when
necessary, for example, integrating stronger
cryptographic measures. Conceptual design of
the required security services and their implementation are investigated and developed in various projects, such as SeVeCom [6] and E-safety
Vehicle Intrusion proTected Application
(EVITA) [15], whose results serve as input for
harmonization within COMeSafety and the
Security Group of the C2C CC.
MANAGEMENT
The management layer is responsible to ally
applications, networks, and interfaces in a specific implementation. This implementation can
range from a simple standalone unit in a vehicle
(vehicle station) to a complex router/host interaction in a large roadside network.
The central system manager tasks are:
• Manage policy setting and maintenance for
each logical function block in a station.
• Manage (dynamic) interface selection per
application. The decision is criteria-based
on policies, application requirements, and
interface performance/ availability.
• Manage transmit permissions and synchronization, based on physical cross-interference between air interfaces combined with
information priorities.
• Manage security and privacy functions
depending on application type and interface
used.
The respective sub-function blocks defined
are:
• Station management is the high-level management of a station, which handles internal
control over multiple hosts and routers that
belong to one station, external control and
communication between stations as far as
required for management purposes, initialization and configuration of (parts of) a station, and decision making on which
application will use which interface, including
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dynamic configuration of all involved layers.
• Networking management handles aspects of
various network functions, such as:
–Routing table updates for IPv6 as defined
in ISO 21210 [16]
–General geo-networking management
–Medium-specific georouting as defined in
ETSI TC ITS
–Optimized non-routing networking for lowlatency, single-hop scenarios
Most medium-specific functionality is defined
in ISO 29281 [17] and under study in ETSI
TC ITS.
• Cross-interface management handles initialization, as well as dynamic configuration
and status reporting from each available
interface. Configuration parameters can be
changed, depending on cross-border differences in regulatory domains. Interference
mitigation between multiple interfaces within the same station; interference mitigation
and load reduction between nearby stations
• The management information base (MIB) is
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a (virtual) data store inside the management box. The purpose of this entity is to
define important variables and data sets
that typically must be present in the management box. A set of definitions can be
found in ISO 29281.
ROADMAP AND NEXT STEPS
The major next step is to develop a set of standards in ETSI. This is already underway. For
example, ETSI already started a new specialist
task force to write a “European profile standard
for the physical and medium access layer of 5
GHz ITS systems.” Thus, the process of consolidation and standardization is set up and is constantly being improved. It can be sensed in the
publication of the European ITS communication
architecture blueprint described in this article
and in the European frequency allocation.
Although the standardization of a European
ITS communication architecture is ongoing,
there are several activities demonstrating the
potential of car-to-car communications. Figure
10 and Fig. 11, which are pictures of current
prototype systems of the automotive industry,
give an impression of future applications: a traffic-light phase assistant and a crossing-traffic
assistant with a special potential for motorcycle
safety. Interoperability and field operational
testing are the next important steps on the way
to the deployment of ITS systems.
ACKNOWLEDGMENT
This article summarizes the work of a common
efort on a unified European ITS communications architecture framework. The results were
jointly created by experts from major European projects and initiatives within the context
of a European Task Force moderated by
COMeSafety, initiated by the European Commission.’
REFERENCES
Figure 10. Application example: traffic light phase assistant.
Figure 11. Application example: crossing traffic assistant.
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[1] COMeSafety Project; http://www.comesafety.org
[2] FRAME; http://www.frame-online.net
[3] Cooperative Systems for Intelligent Road Safety (COOPERS) Project; http://www.coopers-ip.eu/
[4] Cooperative Vehicle-Infrastructure Systems (CVIS) Project; http://www.cvisproject.org/
[5] SAFESPOT Project; http://www.safespot-eu.org/
[6] Secure Vehicular Communication (SeVeCom) Project;
http://www.sevecom.org/
[7] ETSI; http://www.etsi.org/
[8] Car-to-Car Communication Consortium (C2C-CC) Web
site; http://www.car-2-car.org/
[9] IETF; http://www.ietf.org/
[10] ISO; http://www.iso.org
[11] PRE-DRIVE C2X Project; http://www.pre-drive-c2x.eu/
[12] ETSI Technical Committee Intelligent Transportation
System; http://www.etsi.org/WebSite/Technologies/Intel_________________________
ligentTransportSystems.aspx
_______________
[13] R. Bossom et al., “European ITS Communication Architecture — Overall Framework,” COMeSafety System
Architecture, Oct. 2008; http://www.comesafety.org
[14] M. Bechler et al., “D1.2 Refined Architecture,” PREDRIVE C2X deliverable, Feb. 2009; http://www.pre_________
______
drive-c2x.eu/
[15] EVITA Project; http://www.evita-project.org
[16] ISO/DIS 21210, “Intelligent Transport Systems — Continuous Air Interface, Long and Medium Range (CALM)
— Networking Protocols,” Mar. 2008.
[17] ISO/CD 29281, “Intelligent Transport Systems — Communications Access for Land Mobiles (CALM) — Non-IP
Communication Mechanisms,” Sept. 2008.
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ADDITIONAL READING
[1] C2C-CC Manifesto, “Overview of the C2C-CC System,” v.
1.1; http://www.car-to-car.org
BIOGRAPHIES
TIMO KOSCH (timo.kosch@bmw.de)
___________ works as a team manager at BMW Group Research and Technology. He studied
computer science and economics in Darmstadt, Germany,
and Vancouver, Canada, and received his Ph.D. from
Munich University of Technology. His research interests are
in vehicle communications, adaptive systems, and active
safety. He currently serves as the Coordinator for the European project COMeSafety, co-financed by the European
Commission.
ILSE KULP (ilse.kulp@bmw.de)
__________ works as a project manager
at BMW Group Research and Technology. She graduated in
computer science and received her Ph.D. from University of
Passau. Her research interests are in navigation systems,
vehicle communications, adaptive systems, and software
design and architecture.
MARC BECHLER (marc.bechler@bmw.de)
_____________ works as a project
manager at BMW Group Research and Technology. He graduated in computer science and received his Ph.D. from Technical University of Braunschweig. His research interests
include mobile computing, vehicular networking with respect
to system architectures, and communication protocols.
ROBERT LASOWSKI (robert.lasowski@cirquent.de)
________________ works as a
project manager at Cirquent. He studied computer science
in Fulda, Germany, and Boston, Massachusetts, and holds
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a Diploma degree from the University of Applied Sciences
Fulda. His research interest is ad hoc communications,
vehicle communication architecture and marketing, and
deployment strategies for cooperative systems. He is currently working at Germany's FOT SIM-TD.
MARKUS STRAßBERGER (markus.strassberger@bmw.de)
________________ works
as a project manager for BMW Group Forschung und
Technik where he is responsible for projects on Car2X,
including such topics as cooperative systems for active
safety and new telematics services. He has been active in a
number of national and international research programs.
Since 2007 he has chaired the Architecture working group
and is a member of the Technical Committee of the Carto-Car Communication Consortium. He studied computer
science at Technische Universität München and received
his diploma degree in 2004. In 2007 he received his Ph.D.
from the computer science faculty of the University of
Munich. His research interests include mobile and context
aware systems as well as knowledge discovery and management.
B ENJAMIN W EYL (benjamin.weyl@bmw.de)
______________ graduated in
electrical engineering and information technology from
Munich University of Technology in 2003. Since 2003 he
has been engaged in research at BMW R&T, focusing on
security for in-vehicular environments, Car2Car, and
Car2Infrastructure scenarios. In 2007 he received his Ph.D.
from Darmstadt University of Technology. He is chair of the
Security WG of the Car2Car Communication Consortium
and has been active in various research projects such as
the FP6 IST project DAIDALOS. He is currently active within
the FP7 IST project EVITA.
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WAVE: A Tutorial
Roberto A. Uzcátegui, Universidad Nacional Experimental Politécnica “Antonio José de Sucre”
Guillermo Acosta-Marum, Georgia Institute of Technology
ABSTRACT
Intelligent transportation systems have been
under development since at least the early 1990s.
The rationale behind the concept is to automate
the interactions among vehicles and infrastructure to achieve high levels of security, comfort, and efficiency. Communications, in general,
and networking, in particular, have been essential elements in the evolution of these systems.
The IEEE has developed a system architecture
known as WAVE to provide wireless access in
vehicular environments. This article gives an
overview of the associated standards. The presentation loosely follows the order of the layers
of the open systems interconnection model.
INTRODUCTION
In the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA), the United States
Congress mandated the creation of a program
called Intelligent Vehicle Highway Systems
(IVHS), whose main goals were to increase safety, ameliorate congestion, reduce pollution, and
conserve fossil fuels while vehicles use the
nation’s surface transportation infrastructure.
Responsibility for the program was assigned to
the U. S. Department of Transportation (DOT),
which sought the advice of the Intelligent Transportation Society of America (ITSA) — a nonprofit organization whose members come from
industry and academia, as well as federal, state,
and municipal government — to perform the
assignment. By 1996, the DOT, the ITSA, and
several other interested parties had developed a
procedural framework wherein IVHS services
(or intelligent transportation system [ITS] services, as they are known today) could be systematically planned, defined, and integrated. Known
as the National Intelligent Transportation Systems Architecture (NITSA), this framework has
served as a master plan for ITS initiatives for the
past 13 years.
From the beginning, the NITSA recognized
wireless communications as a cornerstone for
the implementation of many ITS services. At the
time, some applications, such as automated toll
collection, were performed using the spectrum
between 902 MHz and 928 MHz. Unfortunately,
this band was too small and polluted to enable
the envisioned evolution of IVHS communications. Consequently, in 1997, the ITSA petitioned the Federal Communications Commission
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0163-6804/09/$25.00 © 2009 IEEE
(FCC) for 75 MHz of bandwidth in the 5.9-GHz
band with the specific goal of supporting dedicated short-range communications (DSRC) for
ITS. The FCC granted the request in October of
1999. The DSRC-based ITS radio services
received 75 MHz of spectrum in the 5.85–5.925
GHz range.
By July 2002, the ITSA was actively lobbying
the FCC on matters of licensing, service rules,
and possible technologies for the ITS-DSRC
band. The ITSA recommended the adoption of
a single standard for the physical (PHY) and
medium access control (MAC) layers of the
architecture and proposed one developed by the
American Society for Testing and Materials
(ASTM) based on IEEE 802.11 [1] (ASTM’s
E2213-02 [2]). The FCC officially adopted this
recommendation in the 2003–2004 timeframe.
In 2004, an IEEE task group (task group p,
or TGp of the IEEE 802.11 working group)
assumed the role initiated by the ASTM and
started developing an amendment to the 802.11
standard to include vehicular environments. The
document is known as IEEE 802.11p [3]. Another IEEE team (working group 1609) undertook
the task of developing specifications to cover
additional layers in the protocol suite. At the
time of this writing, the IEEE 1609 standards set
consisted of four documents: IEEE 1609.1 [4],
IEEE 1609.2 [5], IEEE 1609.3 [6], and IEEE
1609.4 [7].
Collectively, IEEE 802.11p and IEEE 1609.x
are called wireless access in vehicular environments (WAVE) standards because their goal, as
a whole, is to facilitate the provision of wireless
access in vehicular environments. The conceptual design they portray is called WAVE architecture in this article, and the systems that
implement it are referred to as WAVE systems.
The objective of this article is to give an
overview of the IEEE WAVE standards.
To the extent that the model applies, the presentation of the material loosely follows the
order of the layers in the open systems interconnection (OSI) model from the bottom up. In this
article, we consider only those OSI layers that
are covered by a WAVE standard. This content
arrangement does not correspond to a monotonic progression of the numerical designations
given by the IEEE to the related documents, but
it does convey a general sense of the logical flow
of information inside a WAVE system within the
confines of a sequentially written composition.
We organized the article as follows. First, we
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give a general description of the architecture of
a WAVE system. Then, we follow it with a brief
discussion of the PHY layer and the MAC sublayer (as addressed in IEEE 802.11p), the multichannel coordination mechanism used in WAVE
(that sits atop the MAC sublayer, as specified in
IEEE 1609.4), and the WAVE services at the
network- and transport-layer levels (as described
in IEEE 1609.3). In the next two sections, we
discuss entities that have no counterpart in the
OSI model: the resource manager (IEEE 1609.1)
and the security services (IEEE 1609.2). We
finalize the article with some comments about
the state of the art in research and development
in the field.
WAVE SYSTEM ARCHITECTURE
OVERVIEW
Imagine the following three scenarios:
• An emergency-response vehicle, such as a
fire department truck, rapidly approaches
an intersection with a four-way stop. As it
nears the intersection, a radio device on the
truck sends an electronic message to similar
devices located in all nearby vehicles to preempt the crossroad. The onboard computer
of any of the receiving vehicles first alerts
the driver about the emergency, and then, if
necessary, autonomously slows down the
car to avoid a collision.
• As they drive by the welcome center of the
town that a family is visiting for the weekend, a wireless transceiver in their minivan
receives an announcement from an access
point in the building, advertising free global
positioning system (GPS) maps updated
with information about the tourist attractions for that particular weekend. After
receiving confirmation that the passengers
are interested in this particular information,
the transceiver downloads the maps.
• On the way to work and using the speech
user interface of her car, the doctor connects to her Web-based calendar application and listens to the list of appointments
she has that day.
The first scenario is an example of a publicsafety application that implies vehicle-to-vehicle
(V2V) communications. The second and third
ones are instances of private applications that
entail a vehicle-to-infrastructure (V2I) information exchange. The third one, in particular,
involves traditional Internet access. These are
but three of the potential uses of the WAVE
technology that is the focus of this article (see
Table 1 for more uses). We use these three scenarios to provide concrete illustrations of the
concepts discussed in the rest of this section.
F
User services
Travel and
traffic management
Pre-trip travel information
En route driver information
Route guidance
Ride matching and reservation
Traveler’s services information
Traffic control
Incident management
Travel demand management
Emissions testing and mitigation
Highway rail intersection
Public transportation
management
Public transportation management
En route transit information
Personalized public transit
Public travel security
Electronic payment
Electronic payment services
Commercial vehicle
operations
Commercial vehicle electronic clearance
Automated roadside safety inspection
Onboard safety and security monitoring
Commercial vehicle administrative processes
Hazardous materials security and incident response
Freight mobility
Emergency
management
Emergency notification and personal security
Emergency vehicle management
Disaster response and evacuation
Advanced vehicle
safety systems
Longitudinal collision avoidance
Lateral collision avoidance
Intersection collision avoidance
Vision enhancement for crash avoidance
Safety readiness
Pre-crash restraint deployment
Automated vehicle operation
Information
management
Archived data
Maintenance and
construction management
Maintenance and construction operations
Table 1. User services considered in the version 6.1 of the NITSA.
COMPONENTS OF A WAVE SYSTEM
A WAVE system consists of entities called units
(Fig. 1). Roadside units (RSUs) usually are
installed in light poles, traffic lights, road signs,
and so on; they might change location (for
instance, when transported to a construction
site) but cannot work while in transit. Onboard
units (OBUs) are mounted in vehicles and can
function while moving.
The WAVE architecture supports two protocol
stacks, as shown in Fig. 2. In the terminology of
the OSI model, both stacks use the same physical and data-link layers, and they differ from
each other in the network and transport layers.
The WAVE standards do not specify session,
COMMUNICATION PROTOCOLS
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User services bundles
By default, WAVE units operate independently, exchanging information over a fixed
radio channel known as the control channel
(CCH). However, they also can organize themselves in small networks called WAVE basic service sets (WBSSs), which are similar in nature to
the service sets defined in IEEE 802.11 [1].
WBSSs can consist of OBUs only or a mix of
OBUs and RSUs (Fig. 1). All the members of a
particular WBSS exchange information through
one of several radio channels known as service
channels (SCHs). Through the appropriate portals, a WBSS can connect to a wide-area network (Fig. 1).
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presentation, or application layers. However,
they do introduce two elements that do not fit
easily within the boundaries of the OSI model:
the resource manager and the security services
blocks (Fig. 2).
The two stacks supported by WAVE are traditional Internet Protocol version six (IPv6) and
a proprietary one known as WAVE Short-Message Protocol (WSMP). The reason for having
two protocol stacks is to accommodate high-priority, time-sensitive communications, as well as
more traditional and less demanding exchanges,
such as Transmission Control Protocol/User
Datagram Protocol (TCP/UDP) transactions. An
application like the crossroad pre-emption mentioned before has scarce requirements in terms
RSU
WBSS 3
OBU
WBSS 1
OBU
OBU OBU
WBSS 2
OBU
RSU
WAN
Portal
Figure 1. Illustration of a WAVE system showing the typical locations of the
OBUs and RSUs, the general makeup of the WBSSs, and the way a WBSS can
connect to a WAN through a portal.
Resource manager
OSI model
layer 4
OSI model
layer 3
UDP/TCP
WSMP
IPv6
WME
LLC
OSI model
layer 2
OSI model
layer 1
Multichannel
operation
MLME
extension
WAVE MAC
MLME
WAVE PHY
PLME
Data
plane
IEEE 1609.1
IEEE 1609.2
Security
services
Management
plane
IEEE 1609.3
IEEE 1609.4
IEEE 802.11p
Figure 2. WAVE communication stack indicating the standard that covers
each set of layers. The blocks marked resource manager and security services
do not fit easily within the layered structure of the OSI model.
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of datagram length or complexity but very strict
ones in terms of latency and probability of error.
WSMP enables the application to send short
messages and directly control certain parameters
of the radio resource to maximize the probability
that all the implicated parties will receive the
messages in time. However, WSMP is not
enough to support typical Internet applications,
and these are required to attract private investment that would help spread, and ultimately
reduce, the cost of implementing the systems;
hence the inclusion of IPv6.
For reasons that will be explained in the next
section, the WAVE architecture is based on the
IEEE 802.11 standard [1], which specifies layer
one and part of layer two of the protocol stack
(Fig. 2). Given the differences between the operating environment of an 802.11 wireless local
area network (LAN) and a vehicular environment such as any of the ones described at the
beginning of this section, an amendment to the
standard was required, which is known as IEEE
802.11p. This norm specifies not only the data
transmission portion of the protocols but also
the management functions associated with the
corresponding layer (the physical layer management entity [PLME] and the MAC layer management entity [MLME] blocks in Fig. 2).
Unlike traditional wireless LAN stations,
WAVE units might be required to divide their
time between the CCH and the SCHs. Therefore, the WAVE protocol stack includes a sublayer at the level of the OSI layer two, dedicated
to controlling this multichannel operation. This
sublayer (including the associated management
functions) is specified in IEEE 1609.4.
The remaining part of OSI layer two (the logical link control [LLC]) follows the IEEE 802.2
standard, as described in a later section.
At the level of the OSI layers three and four,
IEEE 1609.3 specifies the aforementioned
WSMP and explains how to incorporate traditional IPv6, UDP, and TCP in the systems. That
document also defines a set of management
functions (labeled WAVE management entity
[WME] in Fig. 2) that must be used to provide
networking services.
The remaining two blocks in Fig. 2 (resource
manager and security services) do not fit easily
in the layered structure of the OSI model. They
are covered by IEEE 1609.1 and IEEE 1609.2,
respectively.
In subsequent sections of this article, we
review the WAVE protocols specified in Table
2, in the order given in the table. Protocols that
appear in Fig. 2 but are not specific to WAVE
(such as LLC, IPv6, TCP, and UDP) are mentioned without details.
PHY AND MAC LAYERS
The WAVE PHY and MAC layers are based on
IEEE 802.11a, and their corresponding standard
is IEEE 802.11p [3]. There are several advantages to basing the WAVE on 802.11 because it
is a stable standard supported by experts in wireless technology. A stable standard is required to
guarantee interoperability between vehicles
made by different manufacturers and the roadside infrastructure in different geographic loca-
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Protocols
Standard
document
Purpose of the standard
OSI model
layer numbers
WAVE PHY and MAC
IEEE 802.11p
Specifies the PHY and MAC functions required of an IEEE 802.11
device to work in the rapidly varying vehicular environment
1 and 2
Multichannel operation
IEEE 1601.4
Provides enhancements to the IEEE 802.11p MAC to support
multichannel operation
2
WAVE networking services
IEEE 1609.3
Provides addressing and routing services within a WAVE system
2, 3, and 4
WAVE resource manager
IEEE 1609.1
Describes an application that allows the interaction of OBUs with
limited computing resources and complex processes
running outside the OBUs in order to give the impression that
the processes are running in the OBUs
N/A
WAVE security services
IEEE 1609.2
Covers the format of secure messages and their processing
N/A
Table 2. A list of the protocols that compose the WAVE communications stack, in the order in which they are presented in this article,
with the designation of the standard that covers each one of them, a brief description of the purpose of the norm, and the corresponding layers in the OSI model.
tions. It also guarantees that the standard will be
maintained in concert with other ongoing developments in the 802.11 family, which enhances
synergies in chipset design to help ensure
economies of scale. However, we require a different version of the 802.11 because we must
support:
• Longer ranges of operation (up to 1000 m)
• The high speed of vehicles
• Extreme multipath environments
• Multiple overlapping ad hoc networks with
extremely high quality of service (QoS)
• The nature of the applications
• A special type of beacon frame
The main requirements, characteristics,
changes, and/or improvements for 802.11p are as
follows [8]:
• Communications in a highly mobile environment
• 10-MHz channels; one-half the data rates of
802.11
• Control channel and six service channels
• Unique ad hoc mode
• Random MAC address
• High accuracy for the received signal
strength indication (RSSI)
• 16 QAM used in the high-speed mobile
environment
• Spectral mask modification
• Option for a more severe operating environment
• Priority control
• Power control
We have noted several times that the high
mobility and extreme multipath environments
present unique challenges in a WAVE system.
The main reason for unique challenges is that
the wideband V2V or V2I channel is “doubly
selective.” This means that its frequency
response varies significantly over the signal
bandwidth, and its time fluctuations happen in
the course of a symbol period. Because WAVE
uses orthogonal frequency division multiplexing
(OFDM), these variations present significant
design challenges in the channel-estimation and
frequency-offset-detection systems of the receiv-
er. In [9, 10], we can find measurement and
modeling studies showing the uniqueness of
these high mobility channels. In [11], we find a
detailed description of the latest draft of this
standard.
MULTICHANNEL OPERATION
A WAVE device must be able to accommodate
an architecture that supports a control channel
and multiple-service channels. The channel coordination is an enhancement to IEEE 802.11
MAC and interacts with IEEE 802.2 LLC and
IEEE 802.11 PHY. In the standard [7], we find
the services that are used to manage channel
coordination and to support MAC service data
unit (MSDU) delivery. There are four services
provided in the standard. The channel routing
service controls the routing of data packets from
the LLC to the designated channel within channel coordination operations in the MAC layer.
The user priority service is used to contend for
medium access using enhanced distributed channel access (EDCA) functionality derived from
IEEE 802.11e [12]. The channel coordination
service coordinates the channel intervals according to the channel synchronization operations of
the MAC layer so that data packets from the
MAC are transmitted on the proper radio frequency (RF) channel. Finally, the MSDU data
transfer service consists of three services: control
channel data transfer, service channel data transfer, and data transfer services. The design of
these three services is concerned mostly with giving a higher priority and direct access to the
WSMP, for which the MAC must be able to
identify the type of data packet (WSMP or IP)
indicated by its EtherType in accordance with
the IEEE 802.2 header.
FUNCTIONAL DESCRIPTION
There are two types of information exchanges in
the WAVE medium: management frames and
data frames. The primary management frame is
the WAVE announcement defined in [7].
WAVE announcement frames are permitted to
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In the data plane,
the WAVE architecture supports two
protocol stacks:
traditional IPv6 and
the unique WSMP.
Both of them operate atop a single LLC
layer. This dual configuration serves to
accommodate highpriority, time-sensitive communications,
as well as less
demanding, transactional exchanges.
be transmitted only in the CCH. Other IEEE
802.11 management frames may be utilized in
the SCH. For data exchanges, data frames containing WAVE short messages (WSMs) can be
exchanged among devices on both the CCH and
the SCH; however, IP data frames are permitted
only in an SCH, and SCH exchanges require the
corresponding devices to be members of a
WBSS. For control channel priority, the EDCA
parameter set is optimized for WSMP data transfer. A predetermined EDCA parameter set must
be used for all WAVE devices when operating in
the CCH. For service channel priority, the
EDCA parameter received within the WAVE
announcement frame of the provider must be
used. Channel coordination utilizes a synchronized scheme based on coordinated universal
time (UTC). This approach assures that all
WAVE devices are monitoring the CCH during
a common time interval (CCH interval). When a
WAVE device joins a WBSS, this channel synchronization approach also assures that the
members of that WBSS are utilizing the corresponding SCH during a common time interval
(SCH interval). The sum of these two intervals
comprises the sync interval.
NETWORKING SERVICES
In the IEEE 1609.3 standard [6], we find the
specification of the functions associated with the
LLC, network, and transport layers of the OSI
model, and the standard calls them WAVE networking services (Fig. 2).
We can functionally divide the WAVE networking services into two sets:
• Data-plane services, whose function is to
carry traffic
• Management-plane services, whose functions are system configuration and maintenance
DATA-PLANE SERVICES
In the data plane, the WAVE architecture supports two protocol stacks: traditional IPv6 and
the unique WSMP. Both of them operate atop a
single LLC layer. This dual configuration serves
to accommodate high-priority, time-sensitive
communications (through WSMP), as well as
less demanding, transactional exchanges
(through UDP/TCP/IP).
At the LLC layer, WAVE devices must implement the type 1 operation specified in [13], the
Sub-Network Access Protocol (SNAP) specified
in [14], and the standard for transmission of IP
datagrams over IEEE 802 networks specified in
RFC 1042.
WAVE devices must implement IPv6, as
specified in RFC 2460, UDP as defined in RFC
768, and TCP as per RFC 793. Manufacturers
are free to implement any other Internet Engineering Task Force (IETF) recommendation
they wish, as long as it does not hinder interoperability with other WAVE devices.
Implementations of WSMP must support a
short-message-forwarding function consisting of
two primitives. Upon receipt of the primitive
WSM-WaveShortMessage.request from a
local (residing on the same device) or a remote
(residing outside the WAVE device) application,
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the WSMP checks that the length of the WSM is
valid (or not) and passes it to the LLC layer for
delivery over the radio link (or not). Upon
receipt of an indication from the LLC of a
received WSM, the WSMP passes it to the destination application (local or remote) by way of a
primitive
second
WSMWaveShortMessage.indication.
MANAGEMENT-PLANE SERVICES
Management-plane services specified in IEEE
1609.3 are collectively known as the WME and
include:
• Application registration
• WBSS management
• Channel usage monitoring
• IPv6 configuration
• Received channel power indicator (RCPI)
monitoring
• Management information base (MIB) maintenance
Application Registration — All the applications that expect to use the WAVE networking
services first must register with the WME. Each
application registers with a unique provider service identifier (PSID). Registration information
is recorded in three tables, namely:
• The ProviderServiceInfo table, which
contains information about the applications
that provide a service.
• The UserServiceInfo table, which contains information about the services that
are of interest to applications residing in
the local unit.
• The ApplicationStatus table, which
contains, among other things, the IP
addresses and ports of the applications for
notification purposes when they reside outside the local unit.
WBSS Management — The WME is in charge
of initiating a WBSS on behalf of any application that provides a service. This may require
one or more of the following operations:
• Link establishment
• Addition or removal of applications from
dynamic WBSSs
• Inclusion (provider side) and retrieval (user
side) of security credentials
• WBSS termination
• Maintenance of the status of each application in the context of a particular WBSS
Channel Usage Monitoring — Although the
standard does not specify how to do it, it mandates that the WME tracks the SCHs usage patterns so that it can choose a channel that is less
likely to be congested when it must establish a
WBSS.
IPv6 Configuration — This service is for managing the link local, global, and multicast IPv6
addresses of the unit as indicated in the corresponding IETF RFCs.
RCPI Monitoring — Any application can query
a remote device about the strength of the
received signal. The WME sends the corresponding request on behalf of the querying
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application. The MLME, not the WME, of the
remote unit answers this request.
MIB Maintenance — The WME maintains a
MIB that contains system-related and application-related information. The system-related
information includes network information
(router, gateway, and Domain Name Service
[DNS] data, among other types), address information (such as local MAC addresses), and
other values, such as registration port, forwarding port, WSM maximum length, and so on. The
application-related information includes the
ProviderServiceInfo, UserServiceInfo,
and ApplicationStatus tables previously
mentioned, as well as channel information, like
channel number, data rate, and transmit power
level.
RESOURCE MANAGER
definition of a WAVE application called the
resource manager (RM), whose purpose is to
give certain processes access to the system communication resources.
The RM is located in either an RSU or an
OBU. It receives requests from applications that
run in computers that are located remotely from
its host unit. These applications are called
resource management applications (RMAs). The
goal of the RMAs is to use the resources of one
or more OBUs. The RM acts as a broker that
relays commands and responses between the
RMAs to the appropriate OBUs. A software
entity called the resource command processor
(RCP) that resides in the OBU executes the
commands sent by the RM on behalf of the
RMAs.
A summary of the operation of the RM layer
is as follows. Each RMA registers with the RM
with which it interacts and specifies, among
other things, the list of resources that it must
use. The RM registers with the WME of its host
unit as a provider. When the RMA becomes
active, the provider’s WME initiates a WBSS
and announces, along with other pertinent information, that there is an RMA wishing to use the
specified set of resources. The WME of an OBU
receiving the announcement notifies the RCP
about the RMA and its list of desired resources.
If there is a match within the set of resources it
administers, the RCP asks the WME of its unit
to join the WBSS and registers as a user. Once
this is done, the RCP responds directly to the
RM. The RM then notifies the RMA that it is in
the presence of an RCP that has some or all of
the resources that the application requires. An
exchange between the RMA and the RCP
begins, by way of the RM. This takes place until
the RMA decides to terminate the session, issuing the appropriate commands to the RCP,
which acknowledges the termination.
The resources that the RMAs may control
include, but are not limited to, read/write memory; user interfaces that are included as part of
the OBU; specialized interfaces to other onboard
equipment; and optional vehicle-security devices
connected to the OBU. All these resources are
mapped into the memory space of the unit. The
commands issued by the RM allow the RMAs to
read, write, reserve, and release portions of this
memory space.
The RM concept reduces the complexity of
the OBUs by freeing them from the requirement
of executing applications onboard the vehicle.
This was considered a simple way of reducing
their production costs, increasing their reliability,
and facilitating the interoperability of units produced by different manufacturers.
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SECURITY SERVICES
WAVE applications face unique safety constraints because of their wide range of operation.
For example, safety applications are time critical; therefore, the processing and bandwidth
overhead must be kept to a minimum. For other
applications, the potential audience may consist
of all vehicles on the road in North America;
therefore, the mechanism used to authenticate
messages must be as flexible and scalable as possible. In each case, we must protect messages
from eavesdropping, spoofing, alterations, and
replay. We also must provide owners the right to
privacy to avoid leaking of personal, identifying,
or linkable information to unauthorized parties.
security services for the WAVE networking stack
and for applications that are intended to run
over the stack. Mechanisms are provided to
authenticate WAVE management messages, to
authenticate messages that do not require
anonymity, and to encrypt messages to a known
recipient. Services include encryption using
another party’s public key and non-anonymous
authentication. Confidentiality (encrypting a message for a specific recipient) avoids the interception or altering of a message. Authenticity
(confirmation of origin of the message) and
integrity (confirmation that the message has not
been altered in transit) avoid tricking a recipient
into accepting incorrect message contents. In
WAVE, anonymity for end users is also a
requirement. Cryptographic mechanisms provide
most of these security requirements, and their
three main families are secret-key or symmetric
algorithms, public-key or asymmetric algorithms,
and hash functions.
F
WAVE applications
face unique safety
constraints because
of their wide range
of operation.
For example, safety
applications are time
critical; therefore,
the processing and
bandwidth overhead
must be kept to a
minimum.
SYMMETRIC ALGORITHMS
When two entities (traditionally called Alice and
Bob) want to communicate, they both use secret
data known as a key. Alice uses the key to encrypt
her message; Bob has the same key and can
decrypt it. To provide authenticity and integrity,
Alice uses the key to generate a cryptographic
checksum or message integrity check (MIC), and
the MIC only passes the check if Bob uses the
correct key. A message can be encrypted-only,
authenticated-only, or both. The standard uses
the advanced encryption standard — counter
with cipher block chaining (CBC) MIC (AESCCM) mechanism.
ASYMMETRIC ALGORITHMS
We use a keypair, known as the public key and
the private key, which are mathematically related
so that it is extremely difficult to determine the
private key, given only the public key. For an
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The goals of safety,
comfort, and energy
efficiency that
motivated legislators
to call for the
creation of an
intelligent
ground-transportation system in 1991
encrypted message to Bob, Alice uses Bob’s public encryption key. Bob, who knows the corresponding private decryption key, is the only one
who can decrypt it. For an authenticated message to Bob, Alice uses her own private signing
key. A cryptographic checksum generated by a
private key is known as a digital signature. Bob
uses Alice’s public verification key to prove that
it is her message. Digital signatures are particularly useful for securing communications with
parties that have not been encountered previously, such as when broadcasting to a dynamically
changing population.
are as valid today as
HASH FUNCTIONS
they were then,
A cryptographically secure hash function maps
an arbitrary-length input into a fixed-length output (the hash value), such that it is computationally infeasible to find an input that maps to a
specific hash value and two inputs that map to
the same hash value. The standard makes use of
the Secure Hash Algorithm (SHA)-1 hash function, defined in Federal Information Processing
Standard (FIPS) 180-1.
if not more so.
ANONYMITY
Broadcast transmissions from a vehicle operated
by a private citizen should not leak information
that can be used to identify that vehicle to unauthorized recipients. Public safety vehicles do not
generally require anonymity. A vehicle can use
broadcast or transactional applications. In both
cases, the use of these applications should not
compromise anonymity. Additionally, the headers in a transmitted packet might reveal information about the sender (e.g., a fixed source MAC
address). A truly anonymous system must
remove this compromising information. The current standard is focused on protecting message
payloads and does not provide techniques for
making the message headers anonymous. In
addition, mechanisms for providing anonymous
authenticated broadcast messages are not given.
CONCLUDING REMARKS
This article presented a tutorial overview of the
IEEE standards for WAVE, namely, IEEE
802.11p, IEEE 1609.1, IEEE 1609.2, IEEE
1609.3, and IEEE 1609.4. We presented the
material from the perspective of the OSI model,
highlighting both the common points and the
divergences between the two systems.
The WAVE architecture is built on the ubiquitous IEEE 802.11 standard, which gives
WAVE the backing of a sizeable community of
wireless experts and enough market momentum
to make possible the production of complying
devices without having to recover considerable
sunk costs. Basing WAVE on IEEE 802.11
implies that many design choices already were
made when the standardization process started,
but the WAVE environment and applications
are sometimes so different from those of traditional wireless LANs that changes and adaptations were inevitable. This article highlighted
many of them and gave justifications for the less
obvious.
All of the standards reviewed in this article
are near final approval. This does not mean,
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however, that the field is closed to new research
and development contributions. Submissions on
data dissemination, security, applications,
testbeds, channel modeling, MAC protocols, and
many other subjects are sent in significant numbers to conferences and symposia on WAVE
(e.g., the International Conference on Wireless
Access in Vehicular Environments [WAVE] or
the IEEE International Symposium on Wireless
Vehicular Communications [WiVEC]).
At the time of this writing, experimental ITS
networks have been implemented in California,
Michigan, New York, and Virginia to display
and test applications for collision avoidance,
traffic management, emergency response systems, real-time traveler information, and e-commerce [15]. The goals of safety, comfort, and
energy efficiency that motivated legislators to
call for the creation of an intelligent groundtransportation system in 1991 are as valid today
as they were then, if not more so; and in the current global economic climate, ITS may be favorably poised to help create jobs while upgrading
the transportation infrastructure. Many stakeholders from industry, government, and
academia are betting on this [15], and, as this
article shows, WAVE technology has an important role to play in the process.
ACKNOWLEDGMENTS
The authors thank Dr. Wai Chen for inviting
them to write this tutorial for the series “Topics
in Automotive Networking” of the IEEE Communications Magazine. They also thank Dr. Weidong Xiang for inviting them to WAVE 2008:
The First International Conference on Wireless
Access in Vehicular Environments to give the
tutorial on which this article is based.
REFERENCES
[1] IEEE Std 802.11, “IEEE Standard for Information Technology-Telecommunications and Information Exchange
Between Systems-Local and Metropolitan Area Networks-Specific Requirements — Part 11: Wireless LAN
Medium Access Control (MAC) and Physical Layer (PHY)
Specifications,” 2007.
[2] ASTM E 2213, “Standard Specification for Telecommunications and Information Exchange between Roadside
and Vehicle Systems — 5GHz Band Dedicated Short
Range Communications (DSRC) Medium Access Control
(MAC) and Physical Layer (PHY) Specifications,” 2002.
[3] IEEE P802.11p/D3.0, “Draft Amendment to Standard for
Information Technology-Telecommunications and Information Exchange between Systems-Local and
Metropolitan Area Networks-Specific Requirements —
Part 11: Wireless LAN Medium Access Control (MAC)
and Physical Layer (PHY) Specifications-Amendment 7:
Wireless Access in Vehicular Environment,” 2007.
[4] IEEE P1609.1, “Trial-Use Standard for Wireless Access in
Vehicular Environments (WAVE) — Resource Manager,”
2006.
Vehicular Environments (WAVE) — Security Services for
Applications and Management Messages,” 2006.
[6] IEEE Std P1609.3, “IEEE Trial-Use Standard for Wireless
Access in Vehicular Environments (WAVE)-Networking
Services,” 2007.
Vehicular Environments (WAVE) — Multi-Channel Operation,” 2006.
[8] “Conversion of ASTM E 2213-03 to IEEE 802.11x Format,” Doc. IEEE 802.11-04-0363-00-wave, Mar. 2004.
[9] G. Acosta-Marum and M. A. Ingram, “A BER-Based Partitioned Model for a 2.4-GHz Vehicle-to-Vehicle Expressway Channel,” Int’l. J. Wireless Personal Commun., July
2006.
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[10] G. Acosta-Marum and M. A. Ingram, “Six Time- and
Frequency-Selective Empirical Channel Models for
Vehicular Wireless LANs,” Proc. 1st IEEE Int’l. Symp.
Wireless Vehic. Commun. (WiVec 2007), Baltimore, MD,
Sept. 30–Oct. 1, 2007.
[11] D. Jiang and L. Delgrossi, “IEEE 802.11p: Towards
an International Standard for WAVE,” Proc. IEEE
Vehic. Tech. Conf., Singapore, May 11–14, 2008, pp.
2036–40.
[12] IEEE Std 802.11e/D13.0, “IEEE Standard for Information Technology — Telecommunications and Information Exchange between Systems-Local and Metropolitan
Area Networks-Specific Requirements — Part 11: Wireless LAN Medium Access Control (MAC) and Physical
Layer (PHY) Specifications: Medium Access Control
(MAC) Enhancements for Quality of Service (QoS),”
draft standard.
[13] IEEE Std 802.2, “IEEE Standard for Information Technology-Telecommunications and Information Exchange
between Systems-Local and Metropolitan Area Networks-Specific Requirements — Part 2: Logical Link
Control,” 1998.
[14] IEEE Std 802, “IEEE Standard for Local and Metropolitan Area Networks: Overview and Architecture,” 2001.
[15] ITS America, “Letter to the Speaker of the U.S. House
of Representatives, Honorable Nancy Pelosi,” Mar.
2009; http://www.itsa.org/itsa/files/pdf/ITSAEconStimPelosi.pdf
_____
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BIOGRAPHIES
ROBERTO A. UZCÁ TEGUI (ruzcategui@unexpo.edu.ve)
______________ received
a B.Sc. degree in electronic engineering, summa cum
laude, from the Universidad Nacional Experimental Politécnica “Antonio José de Sucre” (UNEXPO), Barquisimeto,
Venezuela. He received a Master of Science in electronic
engineering from the Universidad Simón Bolívar, Caracas,
Venezuela, and a Master of Science in electrical engineering from the Georgia Institute of Technology, Atlanta. Currently, he is a professor in the Department of Electronic
Engineering of the Universidad Nacional Experimental
Politécnica “Antonio José de Sucre.” His research interests
include wired and wireless networks, OFDM, MIMO systems, and channel modeling.
GUILLERMO ACOSTA-MARUM (gacosta@gatech.edu)
___________ received
Bachelor (with Honors) and Master of Engineering degrees
from Stevens Institute of Technology in 1985 and 1987,
and an M.B.A. from the ITAM in 1996. He received his
Ph.D. from the School of Electrical and Computer Engineering at the Georgia Institute of Technology, Atlanta, in
2007. He has been an adjunct instructor in electrical engineering at the Instituto Tecnológico Estudios Superiores de
Monterrey Campus Estado de Mexico (ITESM-CEM), the
Universidad Iberoamericana, and Georgia Tech. His research
interests include wireless LAN, wireless MAN, OFDM,
MIMO, and channel modeling.
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VGSim: An Integrated Networking and
Microscopic Vehicular Mobility
Simulation Platform
Bojin Liu, Behrooz Khorashadi, Haining Du, Dipak Ghosal, Chen-Nee Chuah, and Michael Zhang,
University of California, Davis
ABSTRACT
Simulation is the predominant tool used in
research related to vehicular ad hoc networks. In
this article we first present the key requirements
for accurate simulations that arise from the various applications supported by VANETs, and
review the current state-of the-art VANET simulation tools. We then present VGSim, an integrated networking and microscopic vehicular
mobility simulation platform. VGSim provides
full-fledged wireless network simulation with an
accurate traffic mobility model. These two components are tightly integrated and can interact
dynamically. We discuss the flexibility of VGSim
in adopting different mobility models and also
present simulation results that empirically validate the modified mobility model we implemented. We discuss how VANET applications can be
easily modeled in VGSim, and demonstrate this
using two important applications, Accident Alert
and Variable Speed Limit.
INTRODUCTION
This research is funded in
part by the National Science Foundation under
the grant number CMMI
*0700383. The authors
are solely responsible for
the contents of this article.
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Vehicular ad hoc networks (VANETs) are
mobile wireless networks formed by vehicles
with wireless communication and positioning
capabilities. During the last few years, VANET
has become a very popular field of research both
in academia and in industry. This is both due to
the widespread emergence of robust wireless
networking and positioning technologies, and,
more important, the demand for the next-generation intelligent transportation system to provide
both real-time traffic management and commercial services to vehicles on the road.
Due to the nature of mobile wireless communications and the complex dynamics in real vehicle traffic flow, simulation is the primary tool of
choice to analyze various applications of
VANETs. Sophisticated simulation packages are
available for both wireless networks and vehicular traffic flow; however, few of them can fully
address the challenging problems that arise from
the interdisciplinary nature of VANETs. Therefore, integrating network simulation tools with
0163-6804/09/$25.00 © 2009 IEEE
realistic vehicular traffic simulation packages is
necessary. There are different approaches to
integrating these two simulation packages. However, if the underlying integrated tool cannot fulfill all the requirements imposed by VANET
applications, the results are prone to be erroneous or unrealistic. Therefore, a classification
of VANET applications based on simulation
requirements is necessary for accurate simulation design.
In general, VANET applications can be classified into the following two categories:
• Vehicular driver safety and traffic control
applications: These applications need to
address the issue of how drivers respond to
the control signals disseminated using wireless communication and the resulting
change in the topology of the underlying
VANET. Typical applications are accident
alert, real-time traffic condition update,
and any applications that require driver
coordination through the VANET.
• Infotainment Applications: These applications use VANET as a single- or multihop
communication platform, and do not result
in dramatic change in the topology of the
underlying VANET. Typical applications
include Internet access to vehicles, commercial advertisements, and various peerto-peer applications.
For both of the above classes of applications,
a network communication simulation package
with full protocol stack support is desired. For
vehicular traffic simulation, realistic traffic
mobility models are also required. For infotainment applications, simply integrating these two
simulation packages by using vehicular traffic
traces to determine node movements in network
simulation is sufficient. However, for vehicular
driver safety and traffic control applications,
real-time interactions between the network simulation module and vehicular traffic simulation
module are required.
The remainder of the article is organized as
follows. In the next section we present different
aspects of the most commonly used simulation
methodologies in VANET research (trace driven,
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open-loop, and closed-loop integration). We then
present VGSim, an integrated VANET simulation platform that has full-fledged network protocol support, a realistic microscopic vehicular
traffic model, and the ability to support real-time
interactions between the two modules. In the following section we first present the results that
validate the mobility model in VGSim and then
discuss VGSim’s ability to adopt other mobility
models. We then discuss how VANET applications are developed for simulation analysis in
VGSim. We then showcase vehicular driver safety applications analyzed using VGSim. The final
section concludes this article.
VANET SIMULATION
METHODOLOGIES
SIMULATION REQUIREMENTS AND DESIGN
In general, for VANET simulation there are
three dimensions in the design space: network
simulation, vehicular traffic simulation, and the
integration of these two modules. We conducted
a survey of VANET research published during
the last four years. As our survey shows, besides
in-house simulators, running a network simulator with traffic traces generated by a traffic simulator is the main approach for VANET
simulation (more details in the next section).
The traffic traces specify the vehicle mobility
during simulation. We refer to this method as
the open-loop integration approach. The key disadvantage of this approach is that it cannot capture the dynamic interactions between the
information exchange among the vehicles and/or
roadside sensors and the traffic flow.
Another commonly used approach is the
closed-loop integration approach. In this
approach the traffic simulator is responsible for
specifying vehicle movements throughout the
simulation process, and the network simulator is
responsible for wireless communication. However, signals transmitted using wireless channels
could be used as another type of traffic control
signal, which can result in a change in the vehicles’ mobility. This is especially true for advanced
distributed multihop vehicular driver safety and
traffic control applications. In these applications
driver coordination based on wireless traffic control signals can dramatically change drivers’
behavior (accelerating, decelerating, or changing
lanes), and therefore results in a traffic flow different from what a traditional traffic simulator
could generate. Changes in the traffic flow may
imply changes in the topology of the wireless ad
hoc network formed by the vehicles, which in
turn can have significant impact on the performance of the wireless network. Therefore, a
unique requirement for this type of VANET
simulation is the ability of capturing the “interactions” between wireless communication and
the vehicular mobility model. Figure 1b shows
the details of information flow and the interactions of the closed-loop approach.
On the other hand, not all VANET applications require this “interaction” capability in their
simulation. Infotainment applications, which only
use a VANET as a medium to transmit value
added services such as real-time advertisement
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Generate
Driver behavior/
Mobility model
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NS2, Qualnet
VISSIM, CORSIM,
MANET mobility
Decide Vehicle traffic
and net
topology
Decide
Wireless
communication
(a)
Vehicle traffic
Change of
wireless
connectivity
Change of velocity,
position...
VANET Change Driver behavior/
apps
Mobility model
Network topology
Change of
link quality,
routing
property...
Change of
wireless traffic
control signal...
Wireless communication
Support
NS2, Qualnet,
Jist/SWANS
Figure 1. Information flow of two VANET simulation approaches.
and Internet access service, do not necessarily
affect the underlying topology of the VANET. If
data dissemination is the only application of a
VANET, the current approach of simple integration of a network simulator and a traffic simulator (the open-loop approach) is sufficient. It is,
however, necessary that the adopted network
simulator supports the entire wireless communication network protocol stack to be able to carry
out detailed network performance analysis.
In addition, since VANET simulation platforms are needed for evaluating potential safety/infotainment applications, ease of new
application development should also be considered in the design. Simulation platforms that
adopt the approach of integrating existing traffic
and network simulators may encounter complexities in building new VANET applications. This
is because it requires the expertise in both simulation packages to build an efficient VANET
application. Also, flexibility in adopting different
mobility models and performance issues to support large-scale VANET simulations involving
hundreds or even thousands of communication
nodes (vehicles) are also important factors in the
design of the simulation tool.
RELATED RESEARCH ON
VANET SIMULATION STUDIES
We conducted a survey of VANET research
published during the last four years; due to
space limitation, we only highlight the most relevant.
As discussed above, simulation analysis of
VANETs and related applications requires both
communication network and vehicular traffic
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Simulation approach
Description
Mobility model
Examples
Open-loop, simplistic
mobility model
Network simulator with simplistic MANET or macroscopic
models
MANET models or macroscopic
traffic models
[9, 10]
Open-loop, trace driven
mobility model
Microscopic simulation such as VISSIM generated vehicle
traces fed into network simulator (e.g., NS2, QualNet)
Microscopic traffic models
[11–17]
Closed-loop, realistic
mobility model
Integrating network communication and vehicular traffic
simulation, supporting interaction between the two
Microscopic traffic models
[4, 18–20]
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Table 1. A classification of major simulation approaches in recent VANET research.
simulations. For the communication network
simulation, our survey shows that the majority of
research adopted established network simulators
(NS2 [1]/QualNet [2]). For VANET simulations
that only considered high-level communication
parameters like transmission range, some simple
network simulators were used. While Java in
Simulation Time (JiST)/SWANS [3] is not as
popular as NS2/Qualnet, there are a number of
studies on VANETs based on this platform [4].
OMNet++ with INET Framework [5] is another platform used for simulation analysis of wireless communication.
For vehicular traffic simulations, three types
of vehicle mobility models are typically used:
• Mobility models used in mobile ad hoc networks (MANETs) and variants
• Macroscopic vehicular traffic models
• Microscopic vehicular traffic models
MANET mobility models (e.g., the Random
Way Point model) are not accurate for realistic
vehicular traffic simulation, and can considerably
degrade the accuracy of the simulation results
[4]. Macroscopic traffic models only specify highlevel traffic metrics such as vehicle density and
flow rate. A microscopic vehicular traffic model,
on the other hand, specifies the behavior of each
individual vehicle. As a result, microscopic models can generally provide more realistic mobility
patterns and detailed statistics of vehicular traffic flow.
For simplicity, a large body of work is based
on self-developed macroscopic traffic models.
When more realistic microscopic traffic models
are used, they are based on either high fidelity
traffic simulators such as VISSIM [6], CORSIM
[7], and SUMO [8], or simulators developed by
the researchers.
Table 1 summarizes the main approaches
used in VANET simulation. In the open-loop
approach with a simplistic mobility model,
established network simulators like NS2 were
used for network simulation, and simple vehicular mobility models based on a MANET or simple macroscopic vehicular traffic models were
used to generate vehicular traffic flows [9, 10].
Open-loop means the vehicle mobility model is
specified at the beginning of the simulation,
and underlying attributes of vehicular traffic
flow such as headways between vehicles and
speed are predetermined and do not change as
a result of the VANET application. Figure 1a
shows the information flow of the open-loop
approach. Specifically, the study reported in [9]
describes how to modify NS2 to accommodate
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this type of VANET simulation. The open-loop
approach can also be trace-driven: vehicular
traffic traces generated from high fidelity commercial/non-commercial microscopic vehicular
traffic simulators such as VISSIM [11, 16],
CORSIM [12] or SUMO [15], or empirical traffic traces [13, 14] are used to describe the
mobility of vehicles. The traffic traces specify
each individual vehicle’s movement during the
entire simulation. The study reported in [17] is
another example of this approach; it adopts a
microscopic mobility model (IDM/MOBIL
model) to determine the movement of the vehicles and uses OMNet++ [5] to simulate the
communication network.
Figure 1b shows the information flow for the
closed-loop approach, in which vehicular movements are not predetermined at the start of the
simulation. Instead, the mobility model updates
the vehicle position, velocity, and lane in real
time based not only on the vehicular traffic
flow but also on the traffic flow control signal
received through wireless communication. The
altered mobility of vehicles can in turn affect
the topology of the VANET and consequently
the performance of the data communication
over the wireless network. This closed-loop
information flow between the mobility model
and wireless network simulation modules cannot be provided by the open-loop approach.
Consequently, several studies have adopted this
closed-loop approach for simulation analysis [4,
18–20]. In [4] closed-loop integration is
achieved by integrating the JiST/SWANS network simulator with Street Random Waypoint
(STRAW), a modified version of the Random
Waypoint mobility model. This work also
demostrates the importance of realistic mobility
models for the accuracy of VANET simulation
results. It showed that an unrealistic mobility
model of the vehicle can dramatically affect the
simulation results. The study reported in [18]
also directly supports closed-loop interaction
between the mobility model and the wireless
communication module. It adopts SUMO [8] as
the traffic simulator and OMNet++ [5] for
wireless communication simulation. The interactions between these two modules are achieved
by connecting two simulators through a TCP
connection that is used to transfer control commands to SUMO and vehicle position information to the OMNet++ module. In addition,
[19, 20] are also integrated VANET simulation
platforms based on closed-loop integration
between the two simulation modules. The dif-
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ference between [19, 20] and other closed-loop
approaches is that both network and vehicular
traffic simulation modules are self-developed by
the authors. This, however, makes it difficult to
compare with other research based on more
well-known simulation packages such as NS-2
and VISSIM.
While all approaches can, to some extent, fulfill the requirements of infotainment applications, only closed-loop approaches are suitable
for accurately simulating vehicular driver safety
and traffic control applications.
In order to easily design and analyze different
VANET applications through realistic simulation, we developed a highly efficient and flexible VANET simulation platform: VGSim.
VGSim is efficient in memory usage and suitable for simulating large-scale vehicular wireless networks. It consists of a network simulator
with full protocol stack support, a realistic
microscopic vehicular mobility model, and the
closed-loop approach to integration. VGSim’s
network simulation module is based on SWANS
[3], a Java-based network simulator. The
SWANS network simulator uses JiST, which is
an event driven simulation tool [3]. The JiST
simulation platform is very efficient; it outperforms existing highly optimized simulation tools
in both time and memory usage. A detailed
comparison of the performance efficiency of
JiST/SWANS compared to other major network
simulators can be found in [3]. In fact, the efficiency of JiST/SWANS makes it very suitable
for VANET simulation, which may involve hundreds or even thousands of simultaneously communicating nodes.
In VGSim vehicular movements and applications are transformed into events that are processed by the JiST event driven platform. The
network simulator and the vehicular traffic
model run on a feedback loop that enables the
closed-loop interaction discussed in previous
sections. Information obtained from the
SWANS network simulator is fed into the
mobility model and then based on the mobility
model, updated antenna positions are determined for the SWANS network simulator. Figure 2 shows the architecture of VGSim. Each
entity shown in Fig. 2 has a corresponding class
defined in Java. Instances of the RoadEntity
class represent the road sections and hold multiple Vehicle instances during simulation.
Each Vehicle instance mounts a radio antenna and implements the wireless network communication protocols defined in JiST/SWANS.
Each individual object can produce and respond
to simulation events generated by itself or other
objects. In addition, the SWANS network simulator and vehicular mobility simulator both
update a graphical interface that allows network and vehicular mobility parameters to be
changed dynamically. Visualization is another
important feature for both vehicular traffic and
wireless communication simulation, and many
vehicular traffic and network simulators have
F
RoadCanvas
RoadEntity
Vehicle
VGridApp
RoadsideNode
App
App1
App2
SWANS network stack
Radio
Noise model
RF parameters
Field
Fading
Pathloss
Mobility
Figure 2. A block diagram of the VGSim architecture.
their own visualization packages [1, 6]. Enabling
visualization for vehicular traffic and wireless
communication at the same time in the same
panel is an important feature in VANET simulation, since it can help in visually evaluating
the correctness and effectiveness of VANET
applications. Figure 3 shows a screenshot of
VGSim simulating a four-lane freeway scenario
with a roadside node and VANET enabled
vehicles communicating with each other. It
clearly shows VGSim’s visualization capability
of overlaying communication traffic on top of
vehicular traffic.
The vehicular mobility module of VGSim is
based on the cellular automata (CA) model,
which implements a modified version of the
Nagel and Schreckenberg (N-S) model [21]. The
NS model is a well established CA model in traffic engineering research. However, in the original N-S model, the road is divided into
equal-length cells of 7.5 m, and each vehicle
occupies one cell. The simulation time granularity is 1 s; hence, new vehicle positions are calculated every second using the N-S model. In order
to more accurately reflect real-world traffic, we
modified the original N-S model with finer spatial and temporal resolution, based on the study
reported in [22]. Furthermore, we also added
lane-changing capability into our mobility model.
We discuss the validation of our mobility model
in the next section.
The SWANS network simulator provides full
network protocol support especially for mobile
wireless communication. At the application
layer, SWANS provides the standard application
network interfaces. It includes both UDP and
TCP protocols at the transport layer. We also
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IMPLEMENTATION
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Figure 3. A snapshot of the graphical user interface of VGSim. Lines connecting vehicles show communication links between vehicles.
implemented a simple position-based routing
protocol, which leverages the GPS devices in the
vehicles. SWANS also includes standard 802.11
medium access control (MAC) layer protocol
and several path loss and fading models at the
physical layer.
The introduction of close-loop interaction
between the two simulation modules is achieved
by injecting driver decision process into different applications. At each time step, each driver/vehicle makes the decision on how to change
the speed/position of the vehicle according to
not only traffic conditions perceived, but also
the traffic control messages received from the
wireless channel. Figure 4 shows the interactions between the major VGSim components
during simulation. The RoadEntity object
maintains the main simulation loop by providing an implementation of the run() method of
the Proxiable interface in JiST/SWANS,
which makes the RoadEntity a simulation
entity thread in JiST/SWANS. The r u n ( )
method and the moveVehicle() method of
each vehicle object are invoked at each time
step. Upon invocation, each vehicle object calls
the mobility model object’s updatePos()
method to get an updated position information
according to the mobility model logic. Then the
updated position information is fed into the
application’s update method updateApp().
This method implements the logic of the wireless communication network and traffic control
applications. At the end of each time step, each
vehicle updates its own properties such as the
position for the next time step, speed limit,
probability of acceleration or deceleration, and
the probability of lane change according to
updated application state. These updated properties will result in changes in the behavior of
vehicle movement in the next time steps. In the
case shown in Fig. 4, the mobility model is an
implementation of the N-S model, and the
Variable Speed Limit (VSL) application is
installed on the vehicle.
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MOBILITY MODEL:
VALIDATION AND EXTENSION
As a vital part of VGSim, the mobility model’s
accuracy determines the overall accuracy of the
simulation. In this section we first describe the
modifications we made to the original N-S model
and the validation. Then we describe how
VGSim can be extended to accommodate other
mobility models.
VALIDATION OF THE FINER-GRAINED
N-S MODEL
In VGSim we have adopted the classic N-S
mobility model used extensively in vehicular traffic engineering research. The original N-S
model’s temporal-spatial resolution is adequate
for vehicular traffic engineering research. However, for evaluating the performance of wireless
communication, the temporal resolution in terms
of seconds is too coarse-grained. Therefore,
updating the N-S model with a finer resolution is
necessary for accurate VANET simulation. However, merely changing the resolution in the original N-S model results in inaccurate vehicular
traffic generation. Therefore, we modified the
original N-S model, adding more realistic acceleration, deceleration, and lane changing behaviors. A detailed description of the modified
finer-resolution N-S model is reported in [22].
In order to validate our refined fine-grained
mobility model we compared the data obtained
from our model with real world traffic data. For
the latter, we used the vehicle traces produced
by the NGSIM project [23]. Ideally, the more
accurate the mobility model, the higher the
degree of correlation with the NGSIM data.
Our simulation setup consists of a five-lane
700-ft (213 m) highway. In order to be able to
accurately compare with the NGSIM data, we
must guarantee that the initial and road boundary conditions in our simulation are the same as
those in the NGSIM data set [23]. The details of
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vsl:Application
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Network stack
moveVehicle()
updatePos(pos:Position)
npos:Position
updateApp(npos:Position)
[Protocol calls]
run()
updateProp()
Figure 4. Interactions among the VGSim components.
how we reproduce the initial and road boundary
conditions in our simulation can be found in
[22].
Our comparison is based on the fundamental
diagram (flow-density diagram) [22]. In order to
show the accuracy of our finer resolution mobility model, we first compare the fundamental diagram for the basic N-S models with that of
NGSIM. It is known that N-S models can produce a triangular flow-density fundamental diagram. However, matching the fundamental
diagram generated by the CA model with real
traffic data is a challenging task. Figure 5a shows
the fundamental diagram generated by the original N-S model (CA). It shows that in this case of
random slowdown noise of 0.8, the CA model
can generate the required triangular shaped diagram; however, it fails to match the NGSIM
data set.
Figure 5b shows the fundamental diagram
generated by our finer resolution model denoted
fCA. This diagram shows that our finer resolution model not only reproduces the classic trian-
gular flow-density diagram, but also matches
with the real traffic data from NSGSIM better
than the original N-S model. This guarantees the
accuracy of VANET simulation at higher spatial
and temporal resolution.
EXTENDING VGSIM TO
OTHER MOBILITY MODELS
As discussed in the previous section, commonly
adopted mobility models in vehicular traffic
engineering may not completely fulfill the
requirements for VANET research. Therefore,
modification of common mobility models or
even incorporating a totally different mobility
model for better VANET simulation may be
required. Because of VGSim’s modular design,
this is easily achieved by providing an implementation for a mobility model interface in Java.
The mobility model interface in VGSim only has
one method that must be implemented
(updatePos() as shown in Fig. 4). The
updatePos() method contains logic of how to
NGSIM vs. CA Pnoise = 0.8
2500
NGSIM vs. fCA Pnoise = 0.8
2500
NGSIM
CA
2000
Flow (vph)
2000
Flow (vph)
NGSIM
fCA
1500
1000
1500
1000
500
500
0
0
0
20
40
60
Density (vpm)
(a)
80
100
120
0
50
100
150
200
Density (vpm)
(b)
Figure 5. Comparison of the fundamental diagrams obtained using different mobility models and NGSIM data set: a) original N-S
model (CA) vs. NGSIM; b) finer resolution N-S model (fCA) v.s. NGSIM
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One accident VSL + Acc Alert variance
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no VGrid
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cations can make use of the service provided by
other applications such as location-aware ad hoc
routing.
APPLICATION EXAMPLE: ACCIDENT ALERT AND
OPTIMAL VARIABLE SPEED LIMIT
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4
2
0
0.05
0.1
0.13
0.16
0.2
0.3
Traffic density
0.4
0.5
0.6
0.7
Figure 6. Average speed variance with one accident (w/ VGrid implies all
vehicles implement the Acc Alert and VSL applications).
update vehicle positions in any time step. Therefore, extending VGSim using other mobility
models simply takes two steps:
1. Implementing a mobility class with
updatePos() method
2. Associating each vehicle with an object of
the mobility class
After the simulation is executed, the
updatePos() is invoked every time step for
each vehicle. All other tasks, including placing
vehicles on the road, ensuring that there are no
collisions, performing wireless communication
simulation, and visualization, do not require any
modification in VGSim. Although VGSim is currently using an in-house implementation of the
mobility model, it is also possible for VGSim to
adopt other standalone microscopic traffic simulators. This is achieved by implementing an
interface wrapper for controlling and/or communicating with the simulator. The ability of extending VGSim to other mobility models ensures
that VGSim is not tied to one specific mobility
model or vehicular traffic simulation platform.
This is a limitation in many other VANET simulators that integrate with standalone traffic simulators.
VGSIM APPLICATION DEVELOPMENT
AND EXAMPLES
VGSIM APPLICATION DEVELOPMENT
Another advantage of VGSim is the ease with
which VANET applications can be developed.
Due to JiST/SWANS’s flexibility of performing
wireless simulation, embedding wireless simulation in the rest of the application logic is simply
achieved by providing a Java class with an implementation of the updateApp() method (Fig.
4). Therefore, it is possible to have multiple
applications executing in the vehicles simultaneously. In fact, in the current VGSim, multiple
applications can be turned on at the same time.
Some applications provide basic services such as
position beaconing. Other more complex appli-
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To demonstrate the capability of our simulator,
we built two VANET traffic control applications:
Accident Alert (Acc Alert) and VSL on top of
VGSim. The Accident Alert application utilizes
the vehicle’s onboard wireless communications
to send alerts to upstream vehicles of the presence of an obstruction in the road ahead. This
will allow them to change out of impacted lanes
earlier and also prevent them from changing
into those lanes. For VSL, vehicles acquire position and velocity information of other vehicles
through wireless communication and then cooperatively compute the appropriate speed limit
for different sections of the road. Both applications are intended to smooth vehicular traffic on
highways. Figure 6 shows the average speed variance with and without the VGSim supporting
Acc Alert and VSL application, with one accident simulated on the road. We can see a significant decrease in variance with the use of VSL
and Acc Alert. Both Acc Alert and VSL applications are vehicular driver safety and traffic control applications. Without VGSim’s support of
closed-loop interaction between the network
simulation and the microscopic vehicle traffic
simulation, it is hard to evaluate the effectiveness of both applications.
CONCLUSION
Simulation is one of the most commonly used
tools in VANET studies. In this article we first
discuss the classification of simulation tools for
VANET applications and the architectural
requirements for accurate simulations. After
presenting a review of simulation tools used in
VANET research, we present VGSim, which can
fulfill most requirements of accurate simulation.
It implements closed-loop integration of realistic
vehicular traffic and a wireless communication
simulation module. It is highly flexible and can
easily adopt different mobility models. The
application development process is easy and suitable for building multiple distributed VANET
applications that can execute concurrently. Additionally, since it executes as a standalone Java
application using the efficient JiST/SWANS
package, it is more resource efficient than
approaches that integrate existing network and
traffic simulators. We validate the accuracy of
the mobility model of our simulator. Finally, we
present results of Accident Alert and VSL as
proof-of-concept applications simulated using
VGSim.
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__________
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[14] D. Li et al.,” A Distance-Based Directional Broadcast
Protocol for Urban Vehicular Ad Hoc Network,” Proc.
Int’l. Conf. Wireless Commun., Networking, and Mobile
Comp. 2007, Sept. 21–25, 2007, pp. 1520–23.
[15] M. Piorkowski et al., “Joint Traffic and Network Simulator for VANETs” MICS 2006, Zurich, Switzerland, Oct.
2006.
[16] C. Lochert et al., “Multiple simulator interlinking environment for IVC,” Proc. ACM VANET ’05, Sept. 2005.
[17] C. Sommer and F. Dressler, “The DYMO Routing Protocol in VANET Scenarios,” Proc. 66th IEEE VTC 2007-Fall,
Baltimore, Maryland, Sept./Oct. 2007, pp. 16–20.
[18] C. Sommer et al., “On the Need for Bidirectional Coupling of Road Traffic Microsimulation and Network
Simulation,” Proc. 1st ACM Int’l. Wksp. Mobility Models Networking Research, May 2008, pp. 41–48.
[19] S. Y. Wang et al., “NCTUns 4.0: An Integrated Simulation Platform for Vehicular Traffic, Communication, and
Network Researches,” Proc. 1st IEEE Int’l. Symp. Wireless Vehic. Commun., Baltimore, MD, Oct. 2007.
[20] C. Gorgorin et al., “An Integrated Vehicular and Network Simulator for Vehicular Ad-Hoc Networks,” Proc.
20th Euro. Simulation Modeling Conf., Oct. 2006.
[21] K. Nagel and M. Schreckenberg, “A Cellular Automaton Model for Freeway Traffic,” J. Physique, vol. 2,
1992, pp. 2221–29.
[22] M. Zhang and H. Du, “Finer-Resolution Cellular
Automata Model for Intervehicle Communication Applications,” 87th Annual Meeting Transportation Research
Board, 2007.
[23] NGSIM; http://ngsim.fhwa.dot.gov
BIOGRAPHIES
B OJIN L IU (frdliu@ucdavis.edu)
___________ is a Ph.D. student in the
Computer Science Department, University of California,
Davis. He received his Bachelor degree in computing from
Hong Kong Polytechnic University. His research interests
include vehicular ad hoc networks, wireless networks, and
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parallel and distributed systems.
BEHROOZ KHORASHADI (bkhorashadi@ucdavis.edu)
______________ is a Ph.D.
student in the Department of Computer Science at the University of California, Davis. He graduated from the University of California, Berkeley in May 2004. He is currently
working in the Networks laboratory with a focus on peerto-peer networks and VGrid (vehicular ad-hoc Networks).
VGrid is a vehicular ad hoc networking and computing grid
for intelligent traffic monitoring and control. The goal is to
evolve the intelligent transportation system (ITS) from a
centralized to a distributed approach, in which vehicles can
cooperatively solve traffic-flow control problems
autonomously. One example application is the lane-merging scenario, especially when visibility is low during storms
or foggy weather.
__________ is a Ph.D. candidate in the
HAINING DU (hndu@ucdavis.edu)
Civil and Environmental Engineering Department at the University of California, Davis. His dissertation research attempts
to develop improved microscopic vehicular traffic models for
distributed traffic control via DSRC enabled vehicles.
D IPAK G HOSAL (dghosal@ucdavis.edu)
_____________ received a B.Tech.
degree in electrical engineering from the Indian Institute of
Technology, Kanpur in 1983 and an M.S. degree in computer science and automation from the Indian Institute of
Science, Bangalore in 1985. He received his Ph.D. degree in
computer science from the University of Louisiana in 1988.
He is currently a professor in the Department of Computer
Science at the University of California, Davis. His primary
research interests are in the areas of high-speed and wireless networks with particular emphasis on the impact of
new technologies on network and higher layer protocols
and applications. He is also interested in the application of
parallel architectures for protocol processing in high-speed
networks and the application of distributed computing
principles in the design of next generation network architectures and server technologies.
CHEN-NEE CHUAH (chuah@ucdavis.edu)
___________ is an associate professor in the Electrical and Computer Engineering Department at the University of California, Davis. She received her
B.S.E.E. from Rutgers University, and her M. S. and Ph.D. in
electrical engineering and computer sciences from the University of California, Berkeley. Her research interests include
Internet measurements, network management, and wireless/mobile computing. She is an Associate Editor for
IEEE/ACM Transactions on Networking.
M ICHAEL Z HANG (hmzhang@ucdavis.edu)
_____________ is a professor in
the Civil and Environmental Engineering Department at the
University of California at Davis. His areas of expertise are
in transportation systems analysis and operations. He
received his B.S.C.E. from Tongji University, Shanghai,
China, and his M.S. and Ph.D. degrees in engineering from
the University of California at Irvine. He is an Area Editor of
the Journal of Networks and Spatial Economics and an
Associate Editor of Transportation Research, Part B:
Methodological.
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Modeling Urban Traffic:
A Cellular Automata Approach
Ozan K. Tonguz and Wantanee Viriyasitavat, Carnegie Mellon University
Fan Bai, General Motors Corporation
ABSTRACT
In this article we introduce a new cellular
automata approach to construct an urban traffic
mobility model. Based on the developed model,
characteristics of global traffic patterns in urban
areas are studied. Our results show that different
control mechanisms used at intersections such as
cycle duration, green split, and coordination of
traffic lights have a significant effect on intervehicle spacing distribution and traffic dynamics.
These findings provide important insights into
the network connectivity behavior of urban traffic, which are essential for designing appropriate
routing protocols for vehicular ad hoc networks
in urban scenarios.
INTRODUCTION
It is clear that vehicular traffic in an urban
area exhibits a different pattern than that
observed in a highway scenario. While a vehicle on a highway can only go straight, due to
the specific topology and geometry of city
roads, a vehicle in a network of roads (e.g.,
streets and avenues in New York City) might
go straight, make a turn, or stop at an intersection. Car motion is no longer restricted to a
one-dimensional pattern; rather, the road network allows two-dimensional motion where the
direction of motion of a vehicle may change at
an intersection. Due to the crossing of different directional flows, the intersections are
equipped with either unsignalized or signalized
traffic controls. Thus, traffic lights as well as
the synchronization effect of traffic lights at
the intersections have a significant impact on
traffic behavior in urban areas. In other words,
allowing traffic to flow in one direction at an
intersection implies the blockage of traffic flow
in the crossing direction. As a result, car
queues may form before an intersection while
the road after the intersection corresponding
to the turning direction is free [1]. The traffic
pattern therefore exhibits great spatial diversity, making car distribution far from uniform.
Thus, modeling global traffic patterns in a
complex road network that comprises a large
number of intersections is a challenging task.
Since there are no realistic and extensive traces
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0163-6804/09/$25.00 © 2009 IEEE
for urban vehicular traffic, in this article we
attempt to develop a new mobility model based
on the cellular automata (CA) concept to study
traffic in urban areas.
The remainder of this article is organized as
follows. In the next section we discuss related
work. We then present an overview of the CA
concept and several fundamental cellular
automata used for modeling vehicular traffic.
The new CA-based mobility model for urban
traffic is proposed and described in the following
section. The details of the simulation setup used
to obtain numerical results are then presented.
Next, we study how intersections and their control mechanisms affect global traffic patterns and
report the main results of the article. The key
implications of the results are discussed in the
following section, and the final section concludes
the article.
RELATED WORK
Existing traffic mobility models can be classified
into two categories based on the modeling
approach: car following and CA. Examples of
mobility models based on car following include
the Manhattan model [2] and street random
waypoint (STRAW) [3]. Models using car following (e.g., the Manhattan model) either do not
support any intersection control mechanisms
such as traffic lights or stop signs, or (e.g.,
STRAW) require real street maps and support
only two intersection control operations: traffic
lights and stop signs. However, current models
cannot support scenarios with more than two
streets per traffic light in a collision-free environment.
The second modeling approach employs the
CA concept. Despite its ease of implementation and simplicity, CA is a powerful tool that
can generate realistic mobility traces. This concept has been used in many traffic engineering
software packages including Simulation of
Urban Mobility (SUMO) [4], TRANSIM [5],
MMTS [6], and RoadSim [7]. SUMO is an
open source microscopic multimodal traffic
simulation package. Unlike the fundamental
CA model, this tool simulates vehicle movement based on space-continuous cellular
automata in which only time is discrete. Other
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CA-based traffic simulators are TRANSIM
and the multi-agent traffic simulator MMTS.
They are widely used proprietary traffic simulator software developed at ETH Zurich.
These simulators have been used to simulate
public and private transportation and human
behavior in Switzerland, and mainly used for
traffic planning strategies. However, due to
their proprietary nature, the implementation
details of both TRANSIM and MMTS are
not publicly available. RoadSim is the most
recent CA-based model developed by Artimy
et al. It uses the basic CA concept with a
Nagel-Schreckenberg (NaSch) model to
determine the movement of each vehicle.
RoadSim currently supports a limited set of
scenarios: highway, racetrack, and urban
streets with one intersection; the network
connectivity exhibited in such scenarios is
studied in [7].
Among several CA-based mobility models
for urban traffic, the work done by Esser and
Schreckenberg [8] is the most similar to our
work. In contrast to [8], however, our work
implements a realistic intersection control
mechanism with traffic signal coordination and
provides rules for realistic motion of turning
vehicles. In addition, traffic patterns in urban
areas are extensively analyzed, whereas such
analyses do not exist in [8]. While the CA
model is a low-fidelity model (compared to the
car following model), extensive investigations
conducted in [9, 10] have shown that despite its
simplicity, the CA model is capable of capturing and reproducing realistic features of traffic
flow. In addition, due to its discrete nature, the
CA model allows very fast implementation and
can simulate a very large network microscopically in real time [8]. In this article we propose
and use a new CA-based mobility model as a
framework to study characteristics of urban
traffic.
CELLULAR AUTOMATA MODEL
CELLULAR AUTOMATA CONCEPT
A cellular automaton (CA) is a discrete computing model which provides a simple yet flexible
platform for simulating complicated systems and
performing complex computation. Generally, it
is an idealization of physical systems in which
both space and time are assumed to be discrete.
Each cellular automaton consists of two components: a set of cells and a set of rules. The problem space of a CA is divided into cells; each cell
can be in one of some finite states. The CA rules
define transitions between the states of these
cells. At each discrete time step, the rules are
applied to each CA generation repeatedly, causing the system to evolve with time. Note that
based on how a cell and rules are defined, CA
can be used to simulate a simple or very complex system.
The simplest cellular automaton for vehicular
traffic simulates traffic on a one-way single-lane
road; hence, a one-dimensional two-state cellular
automaton is used. In this model the problem
space (i.e., road) is represented by a line of cells.
Each cell can be in either state 1 or 0 depending
on the occupancy of the cell. In other words, the
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v current vehicle speed
/* Acceleration step */
if v is less than maximum speed then
increase v by one cell/step
end if
/* Deceleration step */
if a vehicle will collide with vehicle in front with v then
decrease v by one cell/step so that the vehicle stops behind the vehicle in front
end if
/* Randomization step */
if v is greater than 0 then
Decrease v with probability pslow.
end if
/* Movement step */
Update the vehicle speed with v
Vehicle moves forward v cells
Algorithm 1. Vehicle position update algorithm (NaSch model).
cell is in state 1 if it is occupied by a vehicle;
otherwise, it is in state 0. The rules of this cellular automaton define the motion of vehicles. At
each time step, a vehicle can either be at rest or
move forward by one cell if the next cell is
empty. Clearly, the state of each cell entirely
depends on the occupancy of the cell itself and
its two neighboring cells, and the rule can be
formulated as [1]
(t)
(t)
xi(t+1) = (1 – xi(t)) x(t)
i–1 + xi (1 – x i+1),
where xi(t) is the state of cell i at time t, and x(t)
i–1
and x (t)
i+1 are the states of the upstream and
downstream cells at time t, respectively.
ONE-DIMENSIONAL
NAGEL-SCHRECKENBERG MODEL
A more realistic CA rule for one-dimensional
vehicular traffic is the NaSch model proposed by
Nagel and Schreckenberg [11]. In order to take
into account acceleration, random braking, and
individual driving behavior, motion rules used in
the NaSch model are described in Algorithm 1.
Note that for each time step, each vehicle
computes its speed and position based on the
above steps.
TWO-DIMENSIONAL STREET MODEL
Based on NaSch model, Chopard develops a
traffic model for a network of two-dimensional
streets [1]. In this model the motion rules
imposed on vehicles are similar to those used in
the NaSch model with the exception of rules for
vehicles near intersections. To simplify vehicle
movement at a road crossing, Chopard assumes
that a rotary is located at each crossing. In other
words, all vehicles at the road junction (i.e.,
inside the rotary) always move counterclockwise,
and the rotary vehicles have priority over any
entering vehicle. The motion rules of this twodimensional motion model can be found in [1].
This model, however, does not capture the real
traffic behavior as the model gives a higher pri-
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In the case of
non-turning vehicle,
the update
ority to turning traffic than to through traffic. In
the next section we propose a modified CA
model that addresses this issue in order to simulate and analyze more realistic traffic in urban
scenarios.
mechanism is similar
to the one used by
the NaSch model
except the
deceleration step.
In this model, vehicle
may slow down due
to not only the
vehicle in front, but
also the intersection.
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CA-BASED MOBILITY MODEL FOR
URBAN TRAFFIC
The fundamental model for two-dimensional
traffic is the Biham-Middleton-Levine (BML)
model introduced in 1992. In the BML model
each street allows only single-lane one-way traffic, and intersections where two streets intersect
are represented by lattice sites. The states of
horizontal and vertical traffic are updated in
parallel at odd and even discrete time steps,
respectively. In this model vehicles are not
allowed to turn; thus, the number of cars on
each street is entirely determined by the initial
condition. Due to these assumptions, a rotary is
not needed, and the motion rules used to update
the states are similar to those of the one-dimensional NaSch model [11] whose algorithm is
explicitly described in the previous section.
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tion ensures that turning vehicles do not make a
turn at high speed and stop at the intersection
before making a turn. In addition, the second
condition assigns priority to a right-turning vehicle (over a left-turning vehicle) in the case of a
two-way street.
Note that even though horizontal and vertical
traffic are updated at odd and even time steps,
the same motion rules are applied. As opposed
to the NaSch model where cells are updated in
parallel, the state of each cell in our model is
updated sequentially. In other words, the location
of a vehicle in each street is updated only after
the vehicle in front of it (in the same street) is
updated. This feature is incorporated into our
model for incorporating more realistic traffic
behavior, especially in the scenario where traffic
lights are coordinated (usually known as greenwave synchronization). Note that in addition to
the rules defined in our model, there are several
other ways one can specify the motion rules for
two-dimensional urban traffic. However, the
model we develop in this article is a generic
framework that can be tailored to satisfy other
specific requirements; the study presented here
is an illustrative example.
MOTION RULES
INTERSECTION CONTROL MECHANISM
In our model D cells are inserted between each
pair of adjacent lattices (i.e., successive crossings) to construct a segment of the streets. Thus,
each street segment between intersections can
be modeled in the same way as in the NaSch
model. However, due to traffic signals at intersections, additional rules are required for vehicles entering road junctions. Depending on the
turning decision of the vehicle, its position is
updated based on Algorithm 2.
In the case of a non-turning vehicle, the
update mechanism is similar to the one used by
the NaSch model except for the deceleration
step. In this model a vehicle may slow down due
to not only the vehicle in front, but also the
intersection. Note that in the randomization
step, the speed of the vehicle decreases by one
cell/step with a slowdown probability p slow to
take into account the different behavior patterns
of individual drivers. This step is crucial as it
captures the non-deterministic acceleration due
to random external factors and the overreaction
of drivers while slowing down, and its value
depends on the overall driving behavior of people, which may vary with traffic density and time
of the day. High slowdown probability corresponds to drivers who overreact while slowing
down and maintain a larger than required safety
distance to the car in front. This cautious driving
pattern is usually observed in midnight traffic
where the traffic volume is low and cars travel at
a high speed. As a result, these individuals traveling at high speeds tend to decelerate well
ahead of time. On the other hand, a small slowdown probability corresponds to a less cautious
driving pattern, which is usually observed in rush
hour traffic. During this time period, vehicles
travel at low speeds and move closely together;
the intervehicle spacing is small. Hence, the
drivers put on the brakes exactly when they need
to.
In the case of turning vehicles, the first condi-
In addition to the modifications above, we incorporate into the mobility model one of the intersection control operations used in today’s traffic.
Among many types of intersection control, the
three signal operations that have been most used
are pre-timed, actuated, and computer controlled signals. A pre-timed traffic signal is the
most fundamental signaling mechanism, where
the time durations of red and green lights in
each direction are predetermined. Similar to
pre-timed signals, actuated signals have a predetermined green/red light duration. However, an
actuated signal can change its phase (from red
to green, or green to red) before its scheduled
time if the traffic volume is low. Actuated signals
are usually used in rural areas or at night when
the traffic density is very low [12]. Lastly, a computer-controlled signal, unlike the first two signaling modes, does not have predetermined light
intervals. The red/green durations are intelligently computed and dynamically adjusted based
on the current traffic condition. Computer-controlled signals have been implemented in areas
with highly congested traffic such as some parts
of the city of Los Angeles and Washington, DC.
Nevertheless, pre-timed operated signals are the
most commonly used intersection control mechanism in most urban cities. In this article we
therefore assume that the signalized intersections are equipped with pre-timed signals.
In order to realistically simulate the operation of pre-timed signals, there are three necessary parameters that have to be carefully
configured: cycle duration, green split, and traffic signal coordination. Cycle duration (or traffic
light duration) is defined as the amount of time
taken to complete one signal timing cycle; that
is, the amount of time the signal turns green,
changes to yellow, then red, and then green
again. Note that in one cycle duration there is
lost time which takes into account the time an
intersection is unused during the beginning and
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if the vehicle goes straight at the next intersection then
go to Non-turning vehicle
else
go to Turning vehicle
end if
Non-turning vehicle
v current vehicle speed
/* Acceleration step */
if v is less than maximum speed then
increase v by one cell/step
end if
/* Deceleration step */
if Red or yellow light at the intersection then
if a vehicle will collide with vehicle in front or pass the intersection with speed v then
decrease v so that the vehicle stops behind the vehicle in front or at intersection (whichever comes first)
end if
else
if a vehicle will collide with vehicle in front with speed v then
decrease v so that the vehicle stops behind the vehicle in front
end if
end if
/* Randomization step */
if v is greater than 0 then
Decrease v by one cell/step with probability pslow.
end if
/* Movement step */
Update the vehicle speed with v
Vehicle moves forward v cells
Turning vehicle
if The vehicle is not yet at the intersection then
go to Non-turning vehicle and assume red light at the intersection
else
if Red light at the intersection or the destination street is congested then
The vehicle does not move
else
if The vehicle wants to make a right turn, or (it makes a left turn and no upcoming traffic from the opposite direction)
then
The vehicle moves to the destination street
else
The vehicle does not move
end if
end if
end if
Algorithm 2. New vehicle position update algorithm (Tonguz-Viriyasitavat-Bai algorithm).
end of a phase (i.e., when the right of way
changes and light indications of all directions are
red). Green split is the fraction of time in a cycle
duration in which specific movements have the
right of way (green indications). In our model,
since we assume an equal amount of traffic in
each direction, the green split value is fixed at
50/50 (i.e., each traffic direction has an equal
amount of green time at any intersection). The
other important operational parameter is the
traffic signal coordination, which is a method of
establishing relationships between adjacent traffic control signals. This coordination is controlled by the value of signal offset defined as the
time from which the signal turns green until the
signal on the succeeding intersection turns green.
If offset is zero (referred to as simple coordination), all the lights will turn green at the same
time. Thus, with an appropriate offset value, a
series of traffic lights are coordinated in such a
way that they allow continuous traffic flow over
several intersections. In the developed model
these three important parameters are calculated
based on traffic volume, traffic speed, and distance between intersections, as shown in Table
1. Figure 1 shows a snapshot of a traffic pattern
generated by our model.
SIMULATION SETTING
NETWORK TOPOLOGY
In the simulations we assume a 2 km × 2 km network topology with 16 evenly spaced horizontal
and vertical streets; thus, two consecutive intersections are separated by 125 m. Each street is
represented by a line of 5 m cells, and two-way
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Parameters
Values
Fixed parameters
Network density (vehicles/km2)
Turning probability for transit traffic
pslow
Speed limit (km/h)
Signal offset (s)
Lost time (s)
80, 160, 240, 320
0.25 (left), 0.25 (right)
0.5
36
10
2
Variable parameters
Signal cycle duration (s)
Signal coordination
45, 90, 120
Simple, green-wave
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Table 1. Values of parameters used in the simulations.
traffic is assumed on each street. All road junctions are equipped with pre-timed signals whose
parameters are given in Table 1. In addition, the
network topology is assumed to be a torus: when
a vehicle reaches the network boundary, it reappears on the same street on the opposite side of
the network boundary.
TRAFFIC PATTERN
Based on the commuting pattern in highly populated cities such as New York City (NYC), we
observe that there are two types of traffic: nontransit and transit traffic. A non-transit traffic
(NTT) vehicle is defined as a vehicle that may or
may not originate within the urban area but has
a destination site within the urban area. On the
other hand, transit traffic (TT) represents vehicles that only pass through the urban area; both
their source and destination locations are outside the region of interest. Consider the Manhattan business area in NYC; the traffic pattern can
be grouped into four categories:
1 Morning rush hour traffic (8 am–10 am):
During this time period, people commute
from their homes in the uptown area to
their workplaces downtown. Hence, the
traffic in this period is characterized by a
low volume of TT and a high volume of
southbound NTT; the overall traffic volume
is high and traffic speed is low.
2 Lunch time traffic (11 am–1 pm): During
this time period, we observe a moderate
volume of TT and a low volume of NTT in
random directions. Thus, overall we observe
moderate traffic volume with moderate
speed.
3 Evening rush hour traffic (4 pm–6 pm):
The traffic in this time period is similar to
that observed during the morning rush hour
as people commute back to their homes in
the uptown area. Hence, we expect to see a
high volume of northbound NTT and a low
volume of TT.
4 Midnight traffic (1 am–3 am): The traffic in
this period has very low volume but travels
at a high speed.
In this article the developed mobility model
assumes a lunch time traffic pattern where an
NTT vehicle randomly chooses its start and end
locations. Based on the chosen locations, the
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Figure 1. Snapshot of traffic pattern generated
by the CA-based model.
vehicle chooses the shortest path to traverse.
Once it arrives at its destination, the vehicle is
removed from the simulation. On the other
hand, since a transit vehicle does not have a destination within the simulation area, only the start
location is randomly chosen; thus, the number of
transit vehicles is constant throughout the simulations. Because there is no specific path between
source and destination, when a transit vehicle
arrives at an intersection, it makes a turning
decision based on a fixed turning probability. In
our simulations the transit traffic turns left,
right, and goes straight with probability 0.25,
0.25, and 0.5, respectively. In addition, due to
very low NTT volume observed during lunch
time, we assume that 80 percent of total traffic is
TT. Detailed investigation of other scenarios is
an interesting subject for future work.
PARAMETER SETTING
All parameters and their values used in the simulations are summarized in Table 1.
RESULTS
THE EFFECT OF SIGNAL CONTROL OPERATION
Due to the presence of intersections and their
control mechanisms, the movement of traffic in
urban areas is completely different from that
observed on highways. Based on the CA-based
mobility model developed, below we analyze in
detail and qualitatively discuss how intersections
and their control parameters affect the overall
traffic pattern and mobility.
Flow Rate — In this section we study traffic
flow rates that measure the rates at which vehicles pass through an intersection as a function of
time in relation to other traffic parameters. Our
simulations were performed at different traffic
light durations whose values are given in Table
1. Figure 2 shows the average flow rate (the
average is taken over all intersections and simulation runs). The results in Fig. 2 indicate that
the average flow rate depends on the cycle duration. In general, we observe that the average
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flow rate decreases as the cycle duration increases: as the signal cycle increases, the time an
intersection is unused increases, thus resulting in
more wasted time.
Consider a scenario with low traffic density
(80 vehicles/km 2 ) and cycle duration of 120 s
(dotted line in Fig. 2). From the simulations we
observe that the intersections are utilized heavily
(i.e., vehicles pass through the intersection) during the first part of the green light period; during this interval, vehicles that have accumulated
during the previous red light periods will pass
through the intersections. To illustrate , let us
assume that this heavily utilized period lasts for
20 s. Thus, the next 40 s of green time (assuming
a green split value of 50/50) is a “dead” period
in which the intersections are not efficiently utilized. This implies roughly 2/3 of green time
duration is wasted. Therefore, in order to obtain
a more efficient intersection control mechanism,
one might resort to reducing the cycle duration.
On the other extreme, however, when the signal
cycle is too short, the green time duration per
phase is proportionally decreased. Thus, the
minimum time for a cycle duration of 45 s [12] is
usually set to limit the time lost starting and
stopping traffic. Since the cycle duration heavily
influences the traffic characteristics, it is important to use realistic values for it to reflect the
behavior of realistic urban traffic.
Number of Congested Intersections — In
this section an intersection is considered “congested” if at least one vehicle is waiting there for
a green light. Thus, the number of congested
intersections is the number of times the traffic
flows are impeded by intersections. Since the
average flow rate decreases as the cycle duration
increases, the average number of congested
intersections is expected to increase with the signal cycle duration. This intuition is confirmed by
the simulation results shown in Fig. 3. When
traffic signals are coordinated, the average number of congested intersections changes only
slightly during the entire simulation. When the
signals are not coordinated, however, we observe
a large fluctuation in this statistic because the
uncoordinated signals disrupt the traffic flow at
almost all intersections. Vehicles are unlikely to
encounter more than two consecutive green
lights and thus have to stop at almost all intersections. Note that perfect coordinated signals
are difficult to achieve due to different driving
patterns of individuals. Nevertheless, these findings emphasize the importance of choosing realistic values for traffic light duration and signal
coordination in simulations of vehicular traffic in
urban areas.
ANALYSIS OF TRAFFIC PATTERN
Intervehicle Spacing — Figure 4 shows intervehicle spacing distributions for different network
densities. Observe that despite the intersections,
the intervehicle spacing distributions are still well
approximated by theoretical exponential distributions. The best fit Q parameters (i.e., average
intervehicle spacing) for all traffic densities are
computed using the maximum likelihood test
(ML). To determine how well the simulation
results fit the theoretical distributions, we resort
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10 s
45 s
90 s
120 s
600
500
400
300
200
100
0
0
500
1000
1500
Time (s)
Figure 2. The average flow rate over all intersections as a function of time for
different cycle durations. Note that there is an optimal cycle duration that
maximizes the flow rate.
to the Kolmogorov-Smirnov test, and the goodness of fit is measured in terms of (D + , D – )
defined as (D+, D–) = max {F*(x) – F(x), F(x) –
F*(x)}, where F*(n) and F(n) denote the hypothesized exponential distribution and the distribution obtained from simulations, respectively. The
corresponding parameters for the fitted exponential distribution and goodness-of-fit measure for
each traffic density are given in Table 2. We
observe several peaks in the probability mass
function (PMF) plot at integer multiples of the
length of a road segment (125 m) and at 0 m in
Fig. 4 (left). This is because several vehicles are
queued waiting for green lights at intersections.
This result agrees with [13], which also reports
very high vehicle density near intersections
despite using a different vehicle mobility model.
Our results indicate that the observed peaks in
the PMF become less pronounced as the vehicle
density gets smaller and vice versa. Despite the
peaks in the PMF plot, however, the exponential
PDF is a good approximation of the intervehicle
spacing distribution (Fig. 4, right) obtained with
our CA model. Note that for all traffic densities,
the exponential distribution accurately estimates
the intervehicle spacing distribution, especially
for spacings larger than 50 m. This somewhat
counterintuitive finding is consistent with that
observed in highway scenarios where the empirical distribution is well estimated by an exponential distribution [14].
Nonuniformity of Traffic Pattern — In order
to gain insights into the traffic distribution in
urban areas, we analyze spatial traffic distribution from two different perspectives:
• Local viewpoint, where we analyze the patterns formed by vehicles within one road
block
• Global viewpoint, where we investigate the
traffic distribution over an entire network
(across different road blocks)
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Average flow rate at an intersection (vehicles/h)
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Coordinated traffic signals
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30
30
45s
90s
120s
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Number of congested intersections
Number of congested intersections
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20
15
10
5
0
45s
90s
120s
25
20
15
10
5
0
0
300
600
900
0
300
Time (s)
600
900
Time (s)
Figure 3. The average number of congested intersections are plotted against different signal cycle durations. These simulation results
are obtained from a scenario with 80 vehicles/km2 traffic density.
0.1
1
80 vehicles/km2
160 vehicles/km2
240 vehicles/km2
320 vehicles/km2
0.08
0.8
80 vehicles/km2
0.6
160 vehicles/km2
CDF
PMF
0.06
240 vehicles/km2
0.04
0.4
0.02
0.2
0
0
0
500
1000
1500
2000
320 vehicles/km2
Simulations
Exponential CDF
0
Intervehicle spacing (m)
500
1000
1500
2000
Intervehicle spacing (m)
Figure 4. Comparison between simulation results and the theoretical exponential distribution. The dotted and solid lines in the CDF
plot represent perfect exponential distributions and our simulation results, respectively. The traffic signal has 45 s cycle duration and
50/50 green split, and all signals are coordinated.
In the global viewpoint the density of each
road block is computed, and the result shown in
Fig. 5 (left) illustrates how the density of different road blocks in the network varies. Observe
that in a dense network (density of 320 vehicles/km2), while there are some road blocks that
have high traffic density (i.e., eight vehicles within one road block), there is a large portion of
road blocks (i.e., 35 percent) that have no vehicles. Similar behavior is observed across different traffic densities. In a sparse network with
traffic density of 80 vehicles/km 2 , while most
road blocks have low traffic density, we observe
high traffic density in some road segments.
These results further corroborate the previous
snapshot of traffic generated by the CA model
(Fig. 1).
In addition to the global viewpoint, we also
take the local viewpoint where we analyze how
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vehicles are formed within a single road segment. Figure 5 (right) shows that the local traffic
also exhibits a nonuniform distribution. Observe
that over 50 percent of vehicles are within 20 m
of the intersections. This suggests that the region
near intersections can be very dense, while the
middle section of the road block may have very
low traffic density.
DISCUSSION
It is clear that CA is a powerful tool that can be
used to simulate and analyze urban vehicular
traffic. Based on the results of the previous section, several key observations can be made:
•Using the new CA model proposed, the distribution of intervehicle spacing (both the PMF
and CDF) can be computed. The computed
PMF reveals the presence of several peaks at 0
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80 vehicles/km2
160 vehicles/km2
240 vehicles/km2
320 vehicles/km2
0.8
0.9
Fraction of vehicles that are less
than x meters from intersections (CDF)
Fraction of road blocks that
contains less than x vehicles (CDF)
A
0.6
0.4
0.2
0
0.8
0.7
0.6
0.5
0.4
0.3
0.2
80 vehicles/km2
160 vehicles/km2
240 vehicles/km2
320 vehicles/km2
0.1
0
0
2
4
6
8
10
0
10
Number of vehicles in one road block
20
30
40
50
60
Distance from intersection (m)
Figure 5. Traffic density in each road segment and the distribution of vehicles around an intersection. The traffic signal has 45 s cycle
duration, 50/50 green split, and all signals are coordinated.
m, 125 ms, 250 m, and so on, of which the most
prominent one is, as expected, the peak at 0 m.
It is interesting to note that, especially for low
traffic density and/or low penetration ratio of
DSRC technology, exponential distribution is an
excellent approximation to the actual intervehicle spacing distribution.
•In a two-dimensional scenario, clearly the
number of high rises, buildings, and other obstacles determine the transmission coverage area of
a vehicle. If this is known, this information coupled with the exponential distribution of intervehicle spacing can be used to exactly predict the
number of neighbors to a vehicle. This, in turn,
is a very useful piece of information in determining the connectivity pattern of vehicles. Specifically, based on the observation in the previous
section, the exponential distribution is an accurate approximation when the intervehicle spacing is larger than 50 m. Since the network
connectivity of a vehicle mainly depends on the
number of its immediate neighbors, and a vehicle’s radio transmission range usually extends
beyond 50 m, this exponential finding allows us
to determine the connectivity of a vehicle and
analyze the network connectivity of the entire
network. While the exponential distribution is an
approximation, it can facilitate an accurate and
simple analytical framework capable of modeling
network connectivity in urban vehicular ad hoc
networks (VANETs). Such insights are very
important in designing an efficient routing protocol for urban traffic.
•Even though the intervehicle spacing of
both highway and urban traffic can be approximated by the exponential distribution, the connectivity pattern of a vehicle is very different in
these two scenarios. Unlike one-dimensional
traffic as in a highway scenario, a vehicle in
urban areas may be connected to vehicles traveling on the same or different roads. In other
words, a vehicle on a highway is disconnected
from the network if it has no front or back neighbors in the same or opposite direction. However,
a vehicle in an urban area might not be disconnected in such a situation; it is disconnected only
Traffic density
(vehicle/km2)
Average
intervehicle
spacing (m)
(D–, D+)
80
160
240
320
405.4
207.2
140.0
106.3
(2.4, 4.2)
(2.3, 8.2)
(2.7, 11.5)
(3.1, 14.2)
Table 2. K-S test results for intervehicle distributions against the exponential distributions with
different network densities.
when it does not have neighbors in the intersecting directions. Thus, the disconnected network
problem is less pronounced in an urban scenario
than in a highway scenarios.
•Because of richer network connectivity
observed in urban areas, any two vehicles can
communicate through multiple routes (as
opposed to a single path in a highway scenario).
This, in turn, may add flexibility to the design of
a routing protocol whereby the routing in urban
scenarios can be done via multipath routing as
opposed to only the single-path routing used in a
highway scenario.
•Cellular automata-based mobility modeling
of urban vehicular traffic reveals that while some
parts of the region of interest will be very dense,
other parts will be quite sparse (Fig. 1). This
suggests that a broadcast protocol designed for
urban areas will have to be able to deal with
both the broadcast storm problem [15] and disconnected network problem simultaneously.
•It would be interesting to see if a sensor
network that receives real-time traffic data from
all traffic lights could improve flow rate and ease
congestion in urban areas with a centralized
decision and control system. Ultimately, this
approach seems synergistic to dynamic load balancing [16].
•While the simulation and analysis conducted
in this article were based on a regular Manhattan grid topology, we believe that the methodol-
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Based on a new CA
model, we have
investigated how
urban traffic is
affected by intersections and their
control mechanisms.
Our results show
that control mechanisms such as cycle
duration, green split,
and coordination of
traffic lights have a
significant bearing
on traffic dynamics
and inter-vehicle
spacing distribution.
ogy and techniques developed can be used to
study other urban topologies as well (even irregular ones).
•It would be interesting to compare the predictions of the new CA model proposed in this
article with empirical urban traffic traces. This,
in turn, can verify the validity of the mobility
model used in this article or provide valuable
feedback on how to further refine it.
CONCLUSION
Based on a new CA model, we have investigated
how urban traffic is affected by intersections and
their control mechanisms. Our results show that
control mechanisms such as cycle duration,
green split, and coordination of traffic lights
have a significant bearing on traffic dynamics
and intervehicle spacing distribution. Our findings on urban mobility also provide important
insights into the network connectivity pattern
and how a VANET routing protocol should be
designed in urban settings.
REFERENCES
[1] B. Chopard, P. O. Luthi, and P-A. Queloz, “Cellular
Automata Model of Car Traffic in a Two-Dimensional
Street Network,” J. Physics A, 1996.
[2] F. Bai, N. Sadagopan, and A. Helmy, “The IMPORTANT
Framework for Analyzing the Impact of Mobility on
Performance of Routing for Ad Hoc Networks,” Ad Hoc
Net. J., vol. 1, no. 4, Nov. 2003, pp. 383–403.
[3] D. Choffnes and F. E. Bustamante, “An Integrated
Mobility and Traffic Model for Vehicular Wireless Networks,” Proc. ACM Int’l. Wksp. Vehic. Ad Hoc Net.,
Sept. 2005, pp. 69–78.
[4] D. Krajzewicz et al., “SUMO (Simulation of Urban
MObility): An Open-Source Traffic Simulation,” Proc.
4th Middle East Symp. Simulation Modeling, Sept.
2002, pp. 183–87.
[5] K. Nagel et al., “TRANSIMS Traffic Flow Characteristics,”
Los Alamos National Lab. rep. LA-UR-97-3531, Mar.
1999.
[6] Laboratory for Software Technology (ETH Zurich), “Realistic Vehicular Traces;” http://lst.inf.ethz.ch/ad-hoc/cartraces/
___
[7] M. M. Artimy, W. Robertson, and W. J. Phillips, “Connectivity in Inter-vehicle Ad Hoc Networks,” Proc. IEEE Canadian
Conf. Elec. Comp. Eng., vol. 1, 2004, pp. 293–98.
[8] J. Esser and M. Schreckenberg, “Microscopic Simulation
of Urban Traffic Based on Cellular Automata,” Int’l. J.
Modern Physics C, vol. 8, no. 5, 1997, pp. 1025–36.
[9] M. Rickert et al., “Two Lane Traffic Simulations Using
Cellular Automata,” Physica A, vol. 231, 1996, p.
534–50.
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[10] P. Wagner, “Traffic Simulators Using Cellular Automata:
Comparison with Reality,” Proc. World Scientific, 1996.
[11] K. Nagel and M. Schreckenberg, “A Cellular Automaton Model for Freeway Traffic,” J. de Physique I France,
vol. 33, no. 2, 1992, pp. 2221–29.
[12] J. H. Banks, Introduction to Transportation Engineering, 2nd ed., McGraw-Hill, 2002.
[13] M. Fiore and J. Härri, “The Networking Shape of Vehicular
Mobility,” Proc. 9th ACM MobiHoc, 2008, pp. 261–72.
[14] N. Wisitpongphan et al., “Routing in Sparse Vehicular
Ad Hoc Wireless Networks,” IEEE JSAC, Special Issue on
Vehicular Networks, vol. 25, no. 8, Oct. 2007, pp.
1538–56.
[15] N. Wisitpongphan et al., “Broadcast Storm Mitigation
Techniques in Vehicular Ad Hoc Networks,” IEEE Wireless Commun., vol. 14, no. 6, Dec. 2007, pp. 84–94,
Dec. 2007.
[16] O. K. Tonguz and E. Yanmaz, “The Mathematical Theory of Dynamic Load Balancing in Cellular Networks,”
IEEE Trans. Mobile Comp., vol. 7, no. 12, Dec. 2008,
pp. 1504–18.
BIOGRAPHIES
O ZAN K. T ONGUZ (tonguz@ece.cmu.edu)
____________ is a tenured full
professor in the Electrical and Computer Engineering
Department of Carnegie Mellon University (CMU). He currently leads substantial research efforts at CMU in the
broad areas of telecommunications and networking. He
has published about 300 papers in IEEE journals and conference proceedings in the areas of wireless networking,
optical communications, and computer networks. He is the
author (with G. Ferrari) of the book Ad Hoc Wireless Networks: A Communication-Theoretic Perspective (Wiley,
2006). His current research interests include vehicular ad
hoc networks, wireless ad hoc and sensor networks, selforganizing networks, bioinformatics, and security. He currently serves or has served as a consultant or expert for
several companies, major law firms, and government agencies in the United States, Europe, and Asia.
WANTANEE VIRIYASITAVAT (wviriyas@ece.cmu.edu)
____________ is a Ph.D.
candidate in electrical and computer engineering at CMU.
She received her B.S. and M.S. degrees, both from CMU, in
2006. During 2006–2007 she worked as a lecturer in the
Computer Science Department of Mahidol University, Thailand. Her main research interests include traffic mobility
modeling and network protocol design for vehicular ad
hoc networks.
FAN BAI (fan.bai@gm.com)
_________ has been a senior researcher in
the Electrical and Control Integration Laboratory, General
Motors Corporation, since Sept. 2005. Before joining General Motors, he received a B.S. degree in automation engineering from Tsinghua University, Beijing, China, in 1999,
and M.S.E.E. and Ph.D. degrees in electrical engineering
from the University of Southern California, Los Angeles, in
2005. His current research is focused on the discovery of
fundamental principles, and the analysis and design of protocols/systems for next-generation vehicular ad hoc networks.
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NEMO-Enabled Localized Mobility
Support for Internet Access in
Automotive Scenarios
Ignacio Soto, Carlos J. Bernardos, Maria Calderon, and Albert Banchs, University Carlos III of Madrid
Arturo Azcorra, University Carlos III of Madrid and IMDEA Networks
ABSTRACT
1
Some examples are the
work in the IETF MEXT
WG (http://
___
www.ietf.org/html.char_____________
ters/mext-charter.html),
____________
the extension by the ETSI
Technical Committee
Railways Telecommunications
(http://portal.etsi.org/rt/su
mmary_06.asp)
________ of the
original global system for
mobile communicationsrailway (GSM-R) standard to benefit from the
evolution of the GSM
technology, or the Partners for Advanced Transit
and Highways (PATH)
initiative
(http://www.path.berke____________
ley.edu/PATH/
________
Research/currenttransit.ht
___________
ml),
____________ which among other
goals conducts research in
technologies for innovating and enhancing public
transportation solutions.
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This article surveys the major existing
approaches and proposes a novel architecture
to support mobile networks in network-based,
localized mobility domains. Our architecture
enables conventional terminals without mobility
support to obtain connectivity either from fixed
locations or mobile platforms (e.g., vehicles)
and move between them, while keeping their
ongoing sessions. This functionality offers
broadband Internet access in automotive scenarios such as public transportation systems,
where users spend time both in vehicles and at
stations. The key advantage of our proposal, as
compared with current alternatives, is that the
described mobile functionality is provided to
conventional IP devices that lack mobility functionality. We also performed an experimental
evaluation of our proposal that shows that our
architecture improves the quality perceived by
the end users.
INTRODUCTION
Nowadays, users increasingly demand Internet
access everywhere. The current trend in handheld terminals is toward devices that move
away from the traditional phone service model
and incorporate a large number of different
data applications. Equipping terminals with
multiple technologies — for example, third
generation (3G) and wireless local area network (WLAN) — is a widely used solution to
provide ubiquitous Internet access. Internet
access in automotive scenarios is a particularly
relevant case, especially because people in
modern cities spend a lot of time in vehicles.
Although 3G is a possible option, it suffers
from a number of drawbacks, such as capacity
constraints from the point of view of the operator, as well as cost issues from the end-user
perspective.
In the above context, there is a need for an
alternative solution to 3G that provides efficient
broadband Internet access in automotive scenarios. Public transportation systems, such as under-
0163-6804/09/$25.00 © 2009 IEEE
grounds, suburban trains, and city buses, represent one relevant scenario because of the large
number of users and the time spent by these
users both in vehicles and stations. In fact, communications in these environments are receiving
a lot of attention from a number of research and
standardization activities. 1 Other relevant scenarios with similar requirements are those in
which users move around large areas (e.g., airports, exhibition sites, or fairgrounds). In these
areas, attachment points to the Internet might
be available both in fixed locations (such as coffee shops or airport terminals) or in mobile platforms, such as vehicles (e.g., buses that move
between pavilions at a fair or a train that moves
from one terminal to another at an airport).
Users demand the ability to keep their ongoing
communications while changing their point of
attachment to the network as they move around
(e.g., when a user leaves a coffee shop and gets
on a bus).
Currently, NEtwork MObility (NEMO)
solutions are being developed by the Internet
Engineering Task Force (IETF) and the
research community to offer Internet access
from vehicles. Special devices (called mobile
routers [MRs]), located in the vehicles, handle
the communication with the fixed infrastructure
and provide access to passengers’ devices using
a convenient short-range radio technology.
However, in the scenarios mentioned above,
users spend only part of their time in the vehicles because they also move from vehicles to
fixed platforms (e.g., the stations in the public
transportation scenario or the terminals in the
airport scenario). Therefore, an integrated
solution for these scenarios, which considers
Internet access not only from vehicles but also
from associated fixed platforms, is a better
approach.
Traditional Internet Protocol (IP) mobility
mechanisms [1, 2] were based on functionality
residing both in the moving terminals and in the
network. Lately, there is a new trend toward
solutions that enable the mobility of IP devices
within a local domain with only support from the
network. This approach, called network-based
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localized mobility management (NetLMM) [3],
allows conventional IP devices to benefit from
this mobility support. This is very interesting
from the point of view of operators because it
allows them to provide mobility support without
depending on software and complex mobilityrelated configuration in the terminals. The IETF
has standardized Proxy Mobile IPv6 (PMIPv6)
[4], a protocol to provide this functionality. But
this solution has the limitation of not fully supporting mobile networks.
In this article we propose a novel architecture, called NEMO-enabled PMIPv6 (NPMIPv6), which fully integrates mobile networks
in PMIPv6-localized-mobility domains. With our
approach, users can obtain connectivity either
from fixed locations or mobile platforms (e.g.,
vehicles) and can move between them while
keeping their ongoing sessions. N-PMIPv6 architecture exhibits two remarkable characteristics.
First, N-PMIPv6 is totally network-based —
therefore no mobility support is required in the
terminals — and second, the handover performance is improved, both in terms of latency and
signaling overhead.
LMA
Wi Fi
F
ID
Prefix
AR
MT 1
MT 2
Pref1::/64
Pref2::/64
MAG 1
MAG 2
Wi Fi
MAG 1
MAG 2
Wi Fi
Wi Fi
MT 1
MT 2
OVERVIEW OF
MAJOR EXISTING APPROACHES
This section provides an overview of existing
mechanisms developed by the IETF that are relevant for providing Internet access in vehicular
environments. Operators have shown great interest in network-based localized mobility solutions.
Additionally, NEMO approaches are a key element to provide connectivity from vehicles.
Combining both brings the advantages of network-based, localized-mobility solutions to vehicular scenarios. This section reviews the work of
the IETF in this area and highlights the limitations of current solutions.
NETWORK-BASED LOCALIZED MOBILITY
Unlike host-based localized mobility [1], where
mobile terminals (MTs) signal a location
change to the network to update routing states,
NetLMM [3] approaches provide mobility support to moving hosts without their involvement. This is achieved by relocating relevant
functionality for mobility management from
the MT to the network. In a localized mobility
domain (LMD), the network learns through
standard terminal operation, such as router
and neighbor discovery or by means of linklayer support, about the movement of an MT
and coordinates routing state updates without
any mobility-specific support from the terminal. While moving inside the LMD, the MT
keeps its IP address, and the network is in
charge of updating its location in an efficient
manner. PMIPv6 [4] is the NetLMM protocol
proposed by the IETF. This protocol is based
on mobile IPv6 (MIPv6) [2] — it extends
MIPv6 signaling messages and reuses the home
agent (HA) concept.
The core functional entities in the PMIPv6
infrastructure are (Fig. 1):
• Mobile Access Gateway (MAG): This entity
performs the mobility-related signaling on
LMA: Local mobility anchor
MAG: Mobile access gateway
MT: Mobile terminal
Figure 1. Proxy Mobile IPv6 domain.
behalf of an MT that is attached to its
access link. The MAG is usually the access
router for the MT, that is, the first hop
router in the localized mobility management infrastructure. It is responsible for
tracking the movements of the MT in the
access link. There are multiple MAGs in an
LMD.
• Local Mobility Anchor (LMA): This is an
entity within the backbone network that
maintains a collection of routes for individual MTs within the LMD. The routes point
to the MAGs managing the links in which
the MTs are currently located. Packets for
an MT are routed to and from the MT
through tunnels between the LMA and the
corresponding MAG.
After an MT enters an LMD and attaches to
an access link, the MAG in that access link, after
identifying the MT, performs mobility signaling
on behalf of the MT. The MAG sends a proxy
binding update (PBU) to the LMA, associating
its own address with the MT identity (e.g., its
medium access control [MAC] address or an ID
related with its authentication in the network).
Upon receiving this request, the LMA assigns a
prefix to the MT. Then, the LMA sends a proxy
binding acknowledgment (PBA) including the
prefix assigned to the MT to the MAG. It also
creates a binding cache entry and establishes a
bidirectional tunnel to the MAG. Whenever the
MT moves, the new MAG updates the MT location in the LMA and advertises the same prefix
to the MT (through unicast router advertisement
messages), thereby making the IP mobility trans-
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The basic solution
for network mobility
support is quite
similar to the
solution proposed
for host mobility
(mobile IPv6) and
essentially creates a
bidirectional tunnel
between a special
node located in the
home network of
the NEMO (the HA)
and the CoA of
the MR.
parent to the MT. The MT can keep the address
configured when it first entered the LMD, even
after changing its point of attachment within the
network.
NETWORK MOBILITY SUPPORT
To address the requirement of transparent
Internet access from vehicles, the IETF standardized the NEMO Basic Support (NEMO
B.S.) protocol [5]. This protocol defines a
mobile network (or NEtwork that MOves
[NEMO]) as a network whose attachment point
to the Internet varies with time. The router
within the NEMO that connects to the Internet
is called the MR. It is assumed that the NEMO
has a home network where it resides when it is
not moving. Because the NEMO is part of the
home network, the mobile network has configured addresses belonging to one or more
address blocks assigned to the home network:
the mobile network prefixes (MNPs). These
addresses remain assigned to the NEMO when
it is away from home, although they only have
topological meaning when the NEMO is at
home. So, when the NEMO is away from home,
packets addressed to the mobile network nodes
(MNNs) still will be routed to the home network. Additionally, when the NEMO is away
from home, that is, it is in a visited network,
the MR acquires an address from the visited
network, called the care-of address (CoA),
where the routing infrastructure can deliver
packets without additional mechanisms.
The basic solution for network mobility support is quite similar to the solution proposed for
host mobility (mobile IPv6 [2]) and essentially
creates a bidirectional tunnel between a special
node located in the home network of the NEMO
(the HA) and the CoA of the MR. Currently,
route optimization support is being researched,
with special attention being paid to the requirements of the vehicular scenario [6].
THE CURRENT SOLUTION FOR
COMBINING NEMO AND PMIPV6
Both the NEMO and NetLMM solutions provide interesting features that can be combined in
an integrated architecture. Nowadays, it is possible to partially benefit from the following advantages by using NEMO B.S. and PMIPv6:
• Transparent network mobility support: MRs
manage the mobility of a network composed of a set of devices moving together.
• Transparent localized mobility support without node involvement: MRs and MTs can
roam within a PMIPv6 domain without
changing their IP addresses.
Although current mechanisms (i.e., NEMO
B.S. and PMIPv6) can be combined to provide
the advantages described above, this combination does not constitute a full integration
because an MT cannot roam between an MR
and a MAG of the fixed infrastructure without
changing its IP address. This is because the
addresses used within the mobile network belong
to the MNP and not to the prefixes used by
PMIPv6. This means that to support — in a
transparent way — MTs roaming between MRs
and MAGs without any restriction, MTs are
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required to run MIPv6 to manage mobility (that
is, the change of IP address) by themselves. If
MTs must use MIPv6, the mobility support provided within the PMIPv6 domain is no longer
fully network-based because some mobility operations are performed by MTs.
N-PMIPV6 ARCHITECTURE
In this section we propose a novel architecture
that overcomes the shortcomings identified in
the previous section for the current solution for
NEMO support in PMIPv6. Our architecture,
called N-PMIPv6, enables a seamless and efficient integration of mobile networks within a
NetLMM solution, based on PMIPv6, without
adding extra mobility support on terminals (i.e.,
mobility is totally managed by the network) and
improving handover performance. First, an
overview of the architecture is provided, and
subsequently its operation is presented in greater
detail.
OVERVIEW
The key idea of N-PMIPv6 consists in extending the PMIPv6 domain to also include mobile
networks. Both the fixed infrastructure (i.e.,
MAGs) and the mobile networks (i.e., MRs)
belong to the same network operator. With NPMIPv6, an MT attached to a mobile network
is also part of the PMIPv6 domain. Hereinafter,
we refer to an N-PMIPv6-enabled LMD as an
N-PMIPv6 domain. This enables conventional
IP nodes to roam between fixed MAGs and
also between fixed MAGs and MRs, without
changing the IPv6 addresses they are using. As
a result, the handover-related signaling load is
reduced, and the handover performance (i.e.,
the associated latency) is improved when compared to traditional global IP-mobility solutions
(e.g., MIPv6).
Whereas the NEMO B.S. protocol requires
MRs to manage their own mobility, this is not
required in N-PMIPv6, in the same way that NPMIPv6 does not require mobility-related functionality in MTs. This is because the mobility of
MRs and MTs in N-PMIPv6 is managed by the
network (i.e., it is network-based). With NPMIPv6, MTs do not require additional functionality. MRs require functionality to extend
the PMIPv6 domain to mobile networks so that
an MT that attaches to a mobile network is not
required to change its IPv6 address. Because
MRs in N-PMIPv6 perform similar functions to
MAGs in PMIPv6 while being mobile, hereafter
we refer to them with the name moving MAGs
(mMAGs).
The mMAGs extend the PMIPv6 domain by
providing IPv6 prefixes belonging to this domain
to attached MTs and by forwarding their packets
through the LMA. The basic operation of an
mMAG is as follows. When an mMAG attaches
to a fixed MAG, the fixed MAG informs its
LMA about this event by sending a PBU message that contains the identity of the mMAG.
The LMA then delegates an IPv6 prefix to the
mMAG and creates a binding cache entry, associating the mMAG identity with the delegated
prefix and the fixed MAG to which the mMAG
is attached. If the mMAG moves to another
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Whereas the NEMO
LMA binding cache
ID
MT1
mMAG1
MT2
MT3
LMA
Prefix
Pref1::/64
Pref2::/64
Pref3::/64
Pref4::/64
AR
MAG 1
MAG 1
MAG 3
mMAG 1
F
M flag
no
no
no
yes
B.S. protocol requires
MRs to manage their
own mobility, this is
not required in
N-PMIPv6 in the
same way that
N-PMIPv6 does not
require mobility-
Wi Fi
MAG 1
Wi Fi
Wi Fi
Wi Fi
MAG 3
MAG 2
MAG 4
related functionality
in MTs. This is
because the mobility
of MRs and MTs in
Wi Fi
N-PMIPv6 is
Wi Fi
MT 1
managed by the
MT 2
network.
LMA: Local mobility anchor
MAG: Mobile access gateway
mMAG: Moving mobile access gateway
MT:
Mobile terminal
Wi Fi
Fi
Wi Fi
Wi Fi
mMAG 1
Wi Fi
Wi Fi
MT 3
Figure 2. Architecture overview of an N-PMIPv6 domain.
fixed MAG, the LMA updates the binding with
the information of the new MAG. Note that this
is basically the PMIPv6 behavior when a conventional MT connects to a PMIPv6 MAG, that is,
our architecture manages the mobility of an
mMAG in the same way that PMIPv6 manages
the mobility of an MT.
From the point of view of an MT that attaches
to an mMAG, this mMAG behaves as a fixed
MAG of the N-PMIPv6 domain. In particular,
when an MT attaches to an mMAG, the mMAG
informs the LMA and, following PMIPv6 procedures, obtains an IPv6 prefix for the MT. The
LMA then adds a new binding cache entry, associating the ID of the MT with the delegated prefix and the MAG IPv6 address to which it is
attached (i.e., the mMAG address). The LMA
cannot accept requests for these kinds of operations from any node, only from authorized MAGs.
This implies that mMAGs must have a security
association with the LMAs to be able to operate
in the N-PMIPv6 domain. The way this association is created is beyond the scope of this article,
but note that it is not different from the security
association required with any fixed MAG. This
basically means that for practical purposes, we
assume scenarios in which the mMAGs, the fixed
MAGs, and the LMA belong to the same administrative domain, as would be the case in the automotive scenarios described in the introduction.
To deliver IPv6 packets addressed to an MT
attached to a connected mMAG, a change in the
normal operation of a PMIPv6 LMA is introduced. Specifically, we extend LMA functionality
to support recursive look ups in its binding cache
as follows. In a first look up, the LMA obtains
the mMAG to which the MT is attached. After
that, the LMA performs a second look up
searching for this mMAG in its binding cache,
and finds the associated fixed MAG. With this
information, the LMA can encapsulate the
received packets toward the mMAG, through
the appropriate fixed MAG. Then, the mMAG
can forward data packets to the MT. Two nested
tunnels are used to encapsulate data packets
between the LMA and the mMAG: one between
the LMA and the mMAG and another one
between the LMA and the fixed MAG. A new
field, called mMAG (M) flag, is added to the
binding cache used by the LMA to support
recursive look ups. The entries in the binding
cache created/updated by PBUs received from
mMAGs have the M flag set to “yes.” On the
other hand, entries created/updated by PBUs
received from fixed MAGs have the M flag set
to “no.” The use of this flag avoids having the
LMA perform unnecessary recursive look ups in
its binding cache.
DETAILED OPERATION
This section describes in more detail the operation of the N-PMIPv6 architecture, using the
network scenario that appears in Fig. 2 and the
signaling sequence depicted in Fig. 3.
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mMAG 1
MAG 1
MAG 2
LMA
Wi Fi
Wi Fi
Wi Fi
Wi Fi
MT 3
mMAG 1 attaches to MAG 1
mMAG 1’s address =
Pref2::mMAG_1/64
Router advertisement
(Pref2::/64)
Wi Fi
Proxy Binding Update
(mMAG 1, MAG 1)
Proxy Binding Ack
(mMAG 1, MAG 1, Pref2::/64)
MT 3 attaches to mMAG 1
MT 3’s
address =
Pref4::MT_3/64
Router
advertisement
(Pref4::/64)
MT 3 detaches from mMAG 1
F
ID
Prefix
AR
M flag
--
--
--
--
ID
Prefix
AR
M flag
mMAG 1 Pref2::/64 MAG 1
ID
Proxy Binding Update (MT 3, mMAG 1, M)
Proxy Binding Ack (MT 3, mMAG 1, Pref4::/64)
Prefix
AR
no
M flag
MT 3
Pref4::/64 mMAG 1
no
yes
De-Registration Proxy Binding Update
(MT 3, mMAG 1, M)
Proxy Binding Ack (MT 3, mMAG 1, Pref4::/64)
MT 3 attaches to MAG 2
MT 3’s
address =
Pref4::MT_3/64
(no change)
Proxy Binding Update
(MT 3, MAG 2)
Router advertisement (Pref4::/64)
Proxy Binding Ack
(MT 3, MAG 2, Pref4::/64)
ID
Prefix
AR
M flag
MT 3
Pref4::/64 MAG 2
no
no
Figure 3. Detailed operation signaling.
2
To enable the LMA to
know which value the M
flag of an entry should
have, we extend the PBU
message so it contains a
new M flag (carrying this
information). Only PBUs
sent by mMAGs have this
M flag set.
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When an mMAG — mMAG 1 — attaches to
a fixed MAG — MAG 1 — this event is detected by MAG 1 and reported to its serving LMA
by means of a PBU message. If no existing entry
for mMAG 1 is found in the LMA binding cache,
the LMA assigns an IPv6 prefix to the mMAG 1
(Pref2::/64) and creates a new entry in the
cache. This entry includes the information of the
assigned IPv6 prefix and the IPv6 address of the
fixed MAG to which mMAG 1 is attached (i.e.,
MAG 1). The LMA then replies with a PBA
message that includes the IPv6 prefix assigned to
mMAG 1 (Pref2::/64). With this information, MAG 1 sends a unicast router advertisement (RA) message to mMAG 1 so it can form
an IPv6 address and start sending/receiving traffic. While the mMAG moves within the same
domain — roaming between different fixed
MAGs — its IPv6 address does not change.
When an MT — MT 3 — attaches to mMAG
1, mMAG 1 sends a PBU message toward the
LMA, which assigns an IPv6 prefix to MT 3
(Pref4::/64) and creates a new entry for this
MT in its binding cache, setting the M flag of
this entry to “yes.” 2 The LMA then provides
mMAG 1 with the assigned prefix. Finally,
mMAG 1 informs MT 3 about the IPv6 prefix it
must use by sending a unicast RA to the MT.
To hide the network topology and avoid
changing the particular prefix assigned to an
mMAG or an MT while they roam within the
same domain, IP bidirectional tunneling is used.
Following our example, if the LMA receives a
packet from a correspondent node (CN)
addressed to MT 3, it performs a recursive look
up at its binding cache. As a result of this look
up, the packet is sent through a nested tunnel,
the inner header with the source address set to
the LMA and destination address, the mMAG 1,
and the outer header with source address the
LMA and destination address, the MAG 1. The
outer header brings the packet to MAG 1, which
then removes that header. Next, the inner header brings the packet to the mMAG 1. Finally,
mMAG 1 removes the inner header and delivers
the packet to MT 3.
If MT 3 performs an intra N-PMIPv6 domain
handover from mMAG 1 to MAG 2 (Fig. 3),
MAG 2 informs the LMA so it can update the
binding entry accordingly (now MT 3 is attached
to MAG 2 instead of mMAG 1, and the M flag
is set to “no”). The mMAG 1, upon detecting
disconnection of MT 3, sends a deregistration
PBU (a PBU with the lifetime value of zero) to
its LMA, following standard PMIPv6 operation.
If the LMA does not receive a PBU about MT 3
after a pre-configured amount of time, the binding entry is deleted to avoid a stale state at the
LMA binding cache.
SCALABILITY OF THE SOLUTION
An additional advantage of our proposal as compared with PMIPv6 is that it increases the scalability because mMAGs concentrate MTs.
Therefore, when a vehicle moves, instead of a
number of individual MTs changing their point
of attachment to the network with a control
message per MT sent by the MAG to the LMA,
we have just one control message sent by the
MAG to the LMA, indicating the movement of
the mMAG. The cost, from the point of view of
scalability, is having more entries (one per
mMAG) in the binding cache of the LMA, but
this is not a problem as it is always possible to
distribute the LMA function among different
nodes in the network.
PERFORMANCE EVALUATION
In this section we evaluate the performance
improvement achieved with N-PMIPv6 when
compared with the existing approach for NEMO
support
in
PMIPv6
domains
(NEMO+MIPv6+PMIPv6) described previously
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MT’s HA
Transoceanic link
(RTT = 160 ms)
LMA/MR’s HA
CN
Wi Fi
Wi Fi
MAG 2
mMAG 1
Wi Fi
Wi Fi
MAG 2
Wi Fi
M
ov
em
en
t
Wi Fi
CN
Wi Fi
MAG 1
M
ov
em
en
t
MAG 1
Wi Fi
M AG
( RT T L M A )
to-
M AG
( RT T L M A )
to-
Wi Fi
(RTT =
10 ms)
Transoceanic link
(RTT = 160 ms)
LMA
Wi Fi
MR
Wi Fi
Wi Fi
Wi Fi
Wi Fi
MT
MT
mMAG 1
Localized mobility domain
Localized mobility domain
(a)
(b)
Figure 4. Analyzed scenarios: a) N-PMIPv6; b) NEMO+MIPv6+PMIPv6.
in the overview of existing approaches. The main
benefit
of
N-PMIPv6
over
NEMO+MIPv6+PMIPv6 is that N-PMIPv6
does not require mobility support on terminals.
Moreover, in this section we show that this benefit comes at no performance penalty and that NPMIPv6 actually provides better performance
than NEMO+MIPv6+PMIPv6.
Figure 4 shows the two scenarios we consider
in this section. The left part shows an N-PMIPv6
domain consisting of two MAGs, one LMA, one
mMAG, and one MT. The right part shows a
network
deployment
of
the
NEMO+MIPv6+PMIPv6 approach, consisting
of two MAGs, one LMA, one MR and its HA
(called MR’s HA), and one MT and its HA
(MT’s HA). In both scenarios, there is a CN
located on the Internet communicating with the
MT.
From the point of view of performance, the
key
advantage
of
N-PMIPv6
over
NEMO+MIPv6+PMIPv6 is that upon executing
an MT handover to or from a mobile network,
the corresponding signaling is sent only to the
LMA, as opposed to NEMO+MIPv6+PMIPv6,
which requires signaling down to the MT’s HA.
This results in a reduction of the signaling load
in the backbone, as well as shorter handover
latencies.
In the case of an mMAG/MR handover,
because mobility is managed by PMIPv6 (i.e.,
the location of the mMAG/MR is updated at the
LMA by the MAG to which the mMAG/MR is
attached, and no further signaling is required) in
both N-PMIPv6 and NEMO+MIPv6+PMIPv6
solutions, the handover performance is the same.
In this section we concentrate on the performance analysis for the case of the MT handover
because this is the only case in which the performance of both approaches differs.
In the NEMO+MIPv6+PMIPv6 scenario,
the MT and its HA are separated by a
transoceanic link in order to understand the
impact of long round-trip times (RTTs) on performance. The MT is communicating with a CN
that is topologically close to the MT’s HA. The
N-PMIPv6 scenario is equivalent in terms of
functionality and the location of the relevant
network entities. The LMA of the N-PMIPv6
scenario is located in the same place that the
MR’s HA in the NEMO+MIPv6+PMIPv6 scenario is in order to perform a fair comparison.
The location of the MR’s HA has an impact on
the end-to-end delay of data traffic because
every packet sent by a node attached to the MR
must traverse the MR’s HA (i.e., there is no
standardized NEMO route optimization solution
yet).
We estimate the MT-handover latency for
both N-PMIPv6 — handovers from an mMAG
to a MAG or vice versa — and
NEMO+MIPv6+PMIPv6 — handovers from
MAG to MAG. We assume that in the
NEMO+MIPv6+PMIPv6 case, the MT is performing MIPv6 route optimization (RO) with
the CN so data packets do not traverse the MT’s
HA. The MT-handover latency can be estimated
for this case following [7], according to which
latency is approximately equal to one MT-HA
RTT plus one MT-CN RTT, which is roughly
two MT-HA RTTs (we take the RTT measurements of [8]), because of the return routability
signaling required to perform RO with the CN.
For the N-PMIPv6 case, the handover latency is
approximately one mMAG-LMA RTT (for the
case of an MT handover from a fixed MAG to
an mMAG or one MAG-LMA RTT, for the
case of a handover from an mMAG to a fixed
MAG) because updating the LMA with the new
location of the MT is the only required signaling. We further consider a frequency of handovers ranging from one handover every 10
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440
420
400
380
360
340
NEMO+MIPv6+PMIPv6 (RTT MAG-to-LMA = 10 ms)
N–PMIPv6 (RTT MAG-to-LMA = 10 ms)
NEMO+MIPv6+PMIPv6 (RTT MAG-to-LMA = 50 ms)
N–PMIPv6 (RTT MAG-to-LMA = 50ms)
320
300
10
20
30
40
Interhandover time (s)
50
60
User-perceived quality assessment
Figure 5. FTP throughput obtained by N-PMIPv6 compared with
NEMO+MIPv6+PMIPv6.
NEMO+MIPv6+PMIPv6
N–PMIPv6
5
4
3
2
1
10
20
30
40
Interhandover time (s)
50
60
Figure 6. User-perceived video quality assessment.
3
OPNET University Program;
http://www.opnet.com/ser______________
vices/university/
________
4
http://www.videolan.org/
5
http://www.netfilter.org/
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seconds (highly dynamic scenarios) to one handover every 60 seconds (slowly changing scenarios).
We first analyzed the performance of a Transmission Control Protocol (TCP) data transfer by
measuring the average throughput experienced
when transferring a 20 MB data file from the
CN to the MT. Experiments were performed
through simulations with the OPNET tool.3 Two
different values of RTT between the LMA and
the MAGs (RTT MAG-to-LMA) were used in
the simulations: 10 ms (usual case) and 50 ms
(extreme case). This allowed us to evaluate the
impact of the size of the N-PMIPv6 domain on
the overall performance. The results obtained
from the experiments with our approach and
with NEMO+MIPv6+PMIPv6 are illustrated in
Fig. 5. It can be observed that N-PMIPv6
improves the average throughput. Indeed, with
NEMO+MIPv6+PMIPv6, each handover causes
a severe interruption due to the latency associated with the signaling, thus degrading TCP performance. With N-PMIPv6, interruptions are
much shorter because only local signaling is
required and as a result, handovers do not
degrade the throughput performance of TCP as
much as in the case of NEMO+MIPv6+
PMIPv6.
The second application whose performance
we analyzed is video streaming, in particular
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VideoLAN Client (VLC),4 which transmits video
over Real Time Protocol/User Datagram Protocol (RTP/UDP). The performance of this application was evaluated by means of real-life
experiments with the following set up. Video was
streamed from one PC to another, crossing a
third PC. The iptables software5 was configured
in the third PC to introduce interruptions of a
duration and frequency equal to the ones caused
by handovers (for the usual case). We conducted
experiments with 16 real users who assessed the
subjective video quality they perceived for each
experiment. Following International Telecommunication Union (ITU) recommendations for
the subjective evaluation of video and audio
quality [9, 10], we asked the users to rate the
quality of each video on a scale ranging from 5
(excellent quality) to 1 (bad quality). Figure 6
depicts the results obtained, in terms of average
subjective quality and 95 percent confidence
intervals.
The obtained results show that N-PMIPv6
clearly outperforms NEMO+MIPv6+PMIPv6,
especially for highly dynamic environments
(i.e., those in which an MT performs handovers very often). It can be seen that there is
one point in the figure (one handover every 50
seconds) where the subjective quality with NPMIPv6 drops down to the level of
NEMO+MIPv6+PMIPv6. The reason for this
anomaly is that this particular experiment
involved an unfortunate drop of some key
packets that significantly degraded video quality despite the small number of lost packets.
Nonetheless, results show that N-PMIPv6 performs significantly better due to the longer
latency of NEMO+MIPv6+PMIPv6 handovers.
CONCLUSIONS
In this article we provide an overview of the
major existing approaches to support mobile
networks in network-based, localized mobility
domains. Then, we propose N-PMIPv6, a novel
architecture that extends these domains to
include not only fixed points of attachment,
but also mobile ones, achieving a better integration of mobile networks. N-PMIPv6, like
PMIPv6, bases mobility support on network
functionality, thus enabling conventional (i.e.,
not mobility-enabled) IP devices to change
their point of attachment within an LMD without disrupting ongoing communications. As a
result, N-PMIPv6 enables off-the-shelf IP
devices to roam within the fixed infrastructure,
attach to a mobile network and move with it,
and also roam between fixed and mobile points
of attachment while keeping the same IP
address.
A key scenario for our architecture is the provision of Internet access from urban public transportation systems, such as undergrounds, suburban
trains, and city buses. In these systems, providing
connectivity from vehicles and stations is not the
only requirement because this connectivity also
must be maintained while changing vehicles.
Protocols already defined by the IETF could
be combined to achieve a similar functionality to
N-PMIPv6, although at the cost of introducing
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additional complexity at the user terminal. Furthermore, the experimental and simulation
results provided in this article show that the performance of such a combination of protocols is
substantially worse, from a user perspective, than
with N-PMIPv6. Future plans include the implementation of N-PMIPv6 and the experimental
evaluation of the state and processing overhead
in the nodes of the architecture.
ACKNOWLEDGMENT
We would like to thank the users that kindly
participated in the video experiments. We also
thank the anonymous reviewers of this article for
their valuable comments. The research leading
to these results received funding from the European Community Seventh Framework Programme (FP7/2007-2013) under grant agreement
no. 214994. This work also was partially supported by the Spanish government through the
POSEIDON project (TSI2006-12507-C03).
REFERENCES
[1] H. Soliman et al., “Hierarchical Mobile IPv6 Mobility
Management (HMIPv6),” RFC 4140, Aug. 2005.
[2] D. Johnson, C. Perkins, and J. Arkko, “Mobility Support
in IPv6,” RFC 3775, June 2004.
[3] J. Kempf, “Problem Statement for Network-Based Localized Mobility Management (NETLMM),” RFC 4830, Apr.
2007.
[4] S. Gundavelli et al., “Proxy Mobile IPv6,” RFC 5213,
Aug. 2008.
[5] V. Devarapalli et al., “Network Mobility (NEMO) Basic
Support Protocol,” RFC 3963, Jan. 2005.
[6] C. J. Bernardos et al., “VARON: Vehicular Ad-hoc Route
Optimisation for NEMO,” Comp. Commun., vol. 30, no.
8, June 2007, pp. 1765–84.
[7] C. Vogt and M. Zitterbart, “Efficient and Scalable, Endto-End Mobility Support for Reactive and Proactive
Handoffs in IPv6,” IEEE Commun. Mag., vol. 44, no. 6,
June 2006, pp. 74–82.
[8] W. Matthews and L. Cottrell, “The PingER Project:
Active Internet Performance Monitoring for the HENP
Community,” IEEE Commun. Mag., vol. 38, no. 5, May
2000, pp. 130–36.
[9] ITU-T Rec. P.800, “Methods for Subjective Determination of Transmission Quality,” 1996.
[10] ITU-R Rec. BT.500-11, “Methodology for the Subjective
Assessment of the Quality of Television Pictures,” 2002.
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BIOGRAPHIES
_________ received a telecommunicaIGNACIO SOTO (isoto@it.uc3m.es)
tion engineering degree in 1993 and a Ph.D. in telecommunications in 2000, both from the University of Vigo, Spain. In
1999 he joined the University Carlos III of Madrid (UC3M),
where he has been an associate professor since 2001. He was
a research and teaching assistant in telematics engineering at
the University of Valladolid from 1993 to 1999. He has published several papers in technical books, magazines, and conferences, recently in the areas of mobility support in packet
networks and heterogeneous wireless access networks.
CARLOS J. BERNARDOS (cjbc@it.uc3m.es)
________ received a telecommunication engineering degree in 2003 and a Ph.D. in telematics in 2006, both from UC3M, where currently he works as
an associate professor. From 2003 to 2008 he worked at
UC3M as a research and teaching assistant. His current work
focuses on vehicular networks and IP-based mobile communication protocols. His Ph.D. thesis focused on route optimization for mobile networks in IPv6 heterogeneous
environments. He served as TPC chair of WEEDEV 2009.
__________ received a computer
MARIA CALDERON (maria@it.uc3m.es)
science engineering degree in 1991 and a Ph.D. degree in
computer science in 1996, both from the Technical University of Madrid (UPM), Spain. She is an associate professor
in the Telematics Engineering Department of UC3M. She
has published over 25 papers in outstanding magazines
and conferences in the fields of advanced communications,
reliable multicast protocols, programmable networks, network mobility, and IPv6 mobility. Some of the recent European research projects in which she has participated are
E-NEXT, LONG, GCAP, DAIDALOS, and GEONET.
A key scenario for
our architecture is
the provision of
Internet access from
urban public transportation systems.
In these systems,
providing connectivity from vehicles and
stations is not the
only requirement
because this connectivity also must be
maintained while
changing vehicles.
ALBERT BANCHS (banchs@it.uc3m.es)
__________ received his M.Sc. and
Ph.D. degrees in telecommunications from the Technical
University of Catalonia, Spain, in 1997 and 2002, respectively. Since 2003 he has worked at UC3M. His research
interests include performance evaluation and resource allocation of wireless networks. He worked for ICSI in 1997,
for Telefonica I+D in 1998, and for NEC Network Laboratories from 1998 to 2003. He is an Associate Editor for IEEE
Communications Letters and has been a guest editor for
IEEE Wireless Communications and Computer Networks.
A RTURO A ZCORRA (azcorra@it.uc3m.es,
____________ arturo.azcorra
________
@imdea.org) received his Ph.D. in 1989 from UPM. In 1992
______
he received an M.B.A. from Instituto de Empresa. He has
been a full professor at UC3M since 1999. In 2006 he was
appointed director of the international research institute
IMDEA Networks. He has participated in many European
research projects since the Third Framework Program and
is currently the coordinator of the EU project CARMEN. He
has published over 100 scientific papers in prestigious
international magazines and conferences.
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Convergent Technologies
IP Multicast with Applications to
IPTV and Mobile DVB-H
DANIEL MINOLI
Provides a concise guide to current IP Multicast
technology and its applications, with a focus
on IP-based Television (IPTV) and Digital Video
Broadcast-Handheld (DVB-H) applications. Discusses
multicasting in IPv6 environments and Multicast
Listener Discovery (MLD) and covers routing in a
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978-0-470-25815-6 • April 2008 • Hbk • 357pp
$79.95
FRANCISCO HENS and JOSE CABALLERO
Triple Play analyses a number of business
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978-0-470-75367-5 • April 2008 • Pbk
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Telecoms Explained
PAUL WARREN, JOHN DAVIES and DAVID BROWN
Provides an insightful introduction to the major technology
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INA MINEI and JULIAN LUCEK
“Here at last is a single, all-encompassing resource
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The authoritative guide to MPLS, now in its second
edition, fully updated with brand new material.
ANDREI GURTOV
“Within the set of many identifier-locator separation
designs for the Internet, HIP has progressed further than
anything else we have so far. It is time to see what HIP can
do in larger scale in the real world. In order to make that
happen, the world needs a HIP book, and now we have it.”
- Jari Arkko, Internet Area Director, IETF
978-0-470-99790-1 • June 2008 • Pbk • 328pp • 110.00
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Triple Play
Building the converged network
for IP, VoIP and IPTV
MPLS-Enabled Applications:
Emerging Developments and New
Technologies, 2nd Edition
Host Identity Protocol (HIP)
Towards the Secure Mobile Internet
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ICT Futures
Delivering Pervasive, Real-time and Secure
Services
978-0-470-99770-3 • April 2008 • Hbk • 224pp
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Wiley Series on Communications Networking & Distributed Systems
Large Deviations for Gaussian
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Modelling Communication Networks
MICHEL MANDJES
Demonstrates how the Gaussian traffic model arises
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978-0-470-01523-0 • April 2008 • Hbk • 336pp
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Business Models for Sustainable
Telecoms Growth in Developing
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SANJAY KAUL; FUAAD ALI; SUBRAMANIAM JANAKIRAM
and BENGT WATTENSTROM
This book addresses the challenges of creating, facilitating
and maintaining sustainable telecommunications growth
in developing nations. With this focus in mind the authors
present a snapshot of these countries through real life case
studies.
978-0-470-51972-1 • April 2008 • Hbk • 400pp
$70.00
Architecture-Independent
Programming for Wireless Sensor
Networks
AMOL B. BAKSHI and VIKTOR K. PRASANNA
An overview of the important issues and recent
developments in programming methodologies for
sensor networks. Provides a detailed description of
the methodology mode, and introduces system-level
support for architecture-independent programming,
graphical programming, and software synthesis
environment for ATaG.
978-0-471-77889-9 • May 2008 • Hbk • 208pp • $79.95
Wiley Series on Parallel and Distributed Computing
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Why did Samsung develop WiMAX?
We like speed.
Samsung has taken a leading role in WiMAX since the beginning. We were on the board of
the WiMAX Forum and helped develop the iEEE 802.16e standard. We’ve been involved with
everything from infrastructure to chip design and devices. We launched the first commercial
Mobile WiMAX network in the world, then in the United States. Today, we’re working hard
to bring WiMAX technology to everyone. We’re working fast, too.
For the latest information on Samsung and WiMAX, go to www.samsung.com/wss.
©2009 Samsung Telecommunications America, LLC (“Samsung”). All rights reserved.
All product and brand names are trademarks or registered trademarks of their respective companies.
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New! - Tole Sutikno - Universitas Ahmad Dahlan

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