Global Standardization Activities

Organization of ITU-T SG15 in StudyPeriod 2005–2008
Yoichi Maeda, Kenji Nakanishi†, Makoto Murakami,
and Hiroshi Ohta
Abstract
This article introduces the organization of Study Group 15 (SG15) for the study period 2005 to 2008.
The management team consists of one chairman and four vice-chairmen. For the first time since SG15
was founded, a chairman from Japan was elected. SG15 includes 3 Working Parties and 14 Questions.
The activity plans for these Questions are described.

1. Introduction
ITU-T (International Telecommunication Union
Telecommunication Standardization Sector) is aninternational standardization body for electrical communication technologies. ITU-T has revised its organization every four years as the basic study period.
This article introduces the organization of SG (StudyGroup) 15 for the study period 2005 to 2008 [1].
2. Organization
The chairmen and vice-chairmen of all SGs in thisstudy period (2005–2008) were elected through thevote at the ITU-T WTSA (World Telecommunication
Standardization Assembly) meeting held in October
2004 [2]. For SG15, one chairman and four vicechairmen were elected, as shown in Table 1. For thefirst time since SG15 was founded, a chairman fromJapan was chosen. This is a significant step up forJapan, because SG15 is the largest and most active
SG in ITU-T. It indicates that Japanese standardization activities to date have been highly regarded
internationally and that Japan will play an even more
important role in international standardization activities in the future.
At the first SG15 meeting of the new study period,
held from November 29 to December 3, 2004, it wasaccepted that SG15 should consist of three Working
Parties (WPs) and fourteen Questions (Q.s) in thisperiod. WP chairmen and Question rapporteurs wereassigned. Compared with the organization in the lastperiod, the old Questions were shifted to new equivalents as they were except for the old WP2 which wastransferred to SG16 and the incorporation of some
Questions from SG13 and SG17 with a change inTable 1. SG15 management team (Study period 2005–2008)
Title

Name

Function

Chairman

Yoichi Maeda (NTT, Japan)

SG15 Chairman

Vice-chairman

Andrew Nunn (BT, UK)

WP1 Chairman

Vice-chairman

Gastone Bonaventura (TI, Italia)

WP2 Chairman

Vice-chairman

Stephen J. Trowbridge (Lucent, USA)WP3 Chairman

Vice-chairmanShaohua Yu (China Telecom, China)

Public relations management† NTT Access Network Service Systems Laboratories
Chiba-shi, 261-0023 Japan
E-mail: nakanisi@ansl.ntt.co.jp

Vol. 3 No. 6 June 2005

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Global Standardization Activities

SG15
Optical and other transport
network infrastructures

WP1
Access network

Q1
Access network
coordination

Q2
Opticalaccess

Q5
Generaloptical cables

WP2
OTN technology

Q4
Metallicaccess

Q6
Opticalsystems

WP3
OTN structure

Q3
Characteristics
of OTN

Q7
Opticalcomponents

Q9
Protection/
restoration

Q11
Structures/interfaces

Q8
Q10
Optical cables Optical cablesfor submarine for buildings

Q12
Networkarchitectures

Q.E2/SG13
Protection/restoration

Q13
Synchronization

Q.C2/SG17
Packet network
adaptation

Q14
Managementand control

Q.P/SG13Core networkarchitecture

Fig. 1. Organization of SG15 for study period 2005–2008.
Table 2. List of Questions and rapporteurs (Study Period 2005–2008)
Q.

Title

Rapporteur

WP1: Optical and metallic access network
1

Coordination of access network transport standards

John Jay (Corning, USA)

2

Optical systems for fiber access networks

Dave Faulkner (BT, UK)

4

Transceivers for customer access and in-premises phone line networking systemson metallic pairs

Richard Stuart (Infineon, USA)

WP2: Optical transport network technology
5

Characteristics and test methods of optical fibers and cables

Tom Hanson (Corning, USA)

6

Characteristics of optical systems for terrestrial transport networks

Jerry Shrimpton (Ciena, USA)

7

Characteristics of optical components and subsystems

James Matthews (Corning, USA)

8

Characteristics of optical fiber submarine cable systems

Masaharu Ohashi (NTT, Japan)

10

Optical fibers and cables for the access network to and in buildings and homes

Pieter Matthijsse (Draka, Netherlands)

WP3: Optical transport network structure
3

General characteristics of optical transport networks

Hiroshi Ohta (NTT, Japan)

9Transport equipment and network protection/restoration

Ghani Abbas (Marconi, UK)11

Signal structures, interfaces, and interworking for transport networks

Mark L. Jones (Sprint, USA)

12

Transport network architectures

Malcolm Betts (Nortel, Canada)

13

Network synchronization and time distribution performance

Jean L. Ferrant (Alcatel, France)

14

Management and control of transport systems and equipment

Hing-Kam Lam (Lucent, USA)their numbers. The structure of SG15 is shown in Fig.
1 and a list of Questions and rapporteurs is shown inTable 2. The activity plans for the Questions aredescribed below, categorized by WP.
2.1 WP1: Access network
WP1 consists of three Questions: Q.1, Q.2, and Q.4.
Q.1 covers the coordination of access network standards. This topic moved from the previous WP5 toWP1 to join Q.2 and Q.4, which were in WP1 before.
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Q.1 has created and is updating standardization andwork plans for access networks through the exchangeof opinions with other standardization bodies, such asIEEE, ITU-R (ITU Radio-communication Sector),and other ITU-T SGs. The activities of Q.1 show that
ITU-T is providing the core work for international
standardization activities for access networks.
Q.2 is examining Recommendations for opticalaccess systems, such as B-PON (broadband passiveoptical network) and G-PON (gigabit PON). It comNTT Technical Review

Global Standardization Activities

pleted Recommendations for B-PON as the G.983
series and those for G-PON as the G.984 series in theprevious period. These Recommendations are contributing to the global spread of broadband opticalaccess systems. In the new period, Q.2 aims at thefurther spread of broadband optical access systems
through verification of inter-operability for PON
equipment and plans to create documents showing
how to verify it. It intends to create requirements forthe application of WDM (wavelength division multiplexing) technologies in access networks as new Recommendations that support the new generation of
optical access systems. Moreover, Q.2 also plans toactively participate in workshops to advertise the usefulness of inter-operability verification and the newgeneration of optical access systems.
Q.4 is examining Recommendations for metallic
access systems, such as ADSL (asymmetric digital
subscriber line) and VDSL (very-high-speed DSL). It
has made ADSL and VDSL into the leading methods
for broadband access systems by completing ADSL
Recommendations as G.992 series and VDSL Recommendation as G.993.1 in the previous period. Q.4
focused on ADSL specifications with higher speed
and longer reach in the previous period. In the newperiod, it intends to create some DSL specifications
that yield even higher speeds and longer reach thanthe existing ones. One example of such new specifications is VDSL2, which carries DSL signals using ahigher frequency than the existing VDSL. Anotherexample is G.bond*1, which carries any DSL signal
across multiple metallic lines. Q.4 also plans toupgrade the specifications of Home PNA (PhonelineNetworking Alliance) in the new period.
2.2 WP2: optical transport network (OTN)
technology
The questions in WP2 are the same as those of theold WP4; only the question numbers have beenchanged. The organization of WP2 can be roughly
divided into two groups. One group, consisting ofQ.5, Q.8, and Q.10, examines Recommendations
related to optical cables. The other group, consistingof Q.6 and Q.7, examines Recommendations related
to optical systems.
The first group performs several roles as follows.
Q.5 treats general-purpose optical cables such as 1.3µm zero-distribution fiber (G.652). Q.8 treats opticalcables for submarine systems described by the G.97x
series. Q.10 treats optical cables for premises networks. Q.5 and Q.8 maintain existing Recommendations and methods for examining existing opticalVol. 3 No. 6 June 2005

cables. Q.10 focuses on creating specifications fornew optical cables. Q.5 and Q.8 offer wider coverage.
For example, Q.5 studies optical cables with non-zerodispersion for wideband optical transport (G.656) for
WDM systems and will create a Recommendation
associated with a particular optical system. As another example, Q.8 is discussing some transmission system specifications such as regulations for highly efficient forward error correction. Although Q.10 is stillsearching for its target, the appeal of small-bendradius optimized single-mode fiber has been raised.
The second group has several roles. Q.6 is in chargeof an optical transmission interface and Q.7 is responsible for optical transmission devices. Q.6 and Q.7
originally considered the core network mainly, butthey are also studying the specifications of metro networks, which are located between core and accessnetworks and are discussing regulations related to theentire optical network including the access network,
as end-to-end services are becoming more important.
For this reason, they are emphasizing multi-vendorcompatibility, which is important in access networks,
as well as single-vendor compatibility, which isassumed in core networks.
WDM-related technologies are being intensely discussed in Q.6, which is actively assessing compatibility for the metro network in order to propose a“black link”*2, which should be seen as an intermediate form between a black box and a white box, inCWDM (coarse WDM) application Recommendation G.695 for metro networks. Q.6 is also examining
the same Recommendation for DWDM (denseWDM) technology, G.dapp.
2.3 WP3: OTN structure
WP3 has extended its range of activities by incorporating some Questions related to packet transmission technologies from SG13 and SG17. WP3 has thesame organization as in the previous period with theaddition of Q.19 (old WP5) as Q.3 since the incorporated Questions have been unified into the Questionsof SG15. Thus, WP3 now consists of 6 Questions:Q.3, Q.9, Q.11, Q.12, Q.13, and Q.14.
WP3 has been eagerly discussing Ethernet services
over OTN at recent meetings. It is now focused on*1 G.bond: Technology for broadening DSL signal bandwidth bydividing and transmitting a DSL signal across multiple metalliccables. ITU-T Recommendations G.998 series.
*2 Black link: Approach for single channel connection, whichdefines I/O interfaces of WDM filters (white box) and closes
inside specifications of WDM filters (black box). The name comesfrom closing a link between the opposing WDM filters.

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Global Standardization Activities

ASON (automatically switched optical network),
which is the next-generation optical network technology designed to perform dynamic bandwidth management for optical signals in addition to the conventional fixed bandwidth management, since SDH/OTN,
which was a main issue, has been almost completed(SDH: synchronous digital hierarchy). WP3 createsand maintains Recommendations in cooperation withother standardization bodies for related technologies,
such as IEEE for Ethernet and IETF (Internet Engineering Task Force) for ASON.
Q.3 is coordinating OTN-related standardization
activities including optical Ethernet and is examining
the Recommendations for OTN-related terms. The
coordination is important because optical Ethernet
should become the essential infrastructure of NGN(Next Generation Network) and its standardizationmust be carried out in cooperation with the IEEE 802
committee.
Q.9 is studying protection and restoration technologies. It is discussing Ethernet, MPLS (multiprotocollabel switching), and ATM (asynchronous transfermode) taken over from SG13 and issues related topacket transfer protocol taken over from SG17 inaddition to the conventional protection and restoration issues. Through the Ethernet relationship, Q.9 is
examining the equipment architecture Recommendation G.8021 and protection Recommendation
Y.17ethps.
Q.11 has completed OTN frame structure regulations and issued Recommendation G.709. It is also
maintaining the Recommendations for next-generation SDH technologies such as GFP (generic framingprocedure) and LCAS (link capacity adjustment
scheme), which have already been approved as Recommendations and is creating Ethernet-technologyrelated Recommendations such as G.8011, which

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specifies the service framework for Ethernet services.
Q.12 is discussing and defining fundamental network architectures so that other Questions can study
them in detail. Since the old Q.10/13 was unified into
Q.12, it is also standardizing the general networkarchitecture, which is independent of implementation
technologies. In particular, for MPLS, Q.12 is proceeding to create Recommendation G.8110 as a new
specification that is categorized as a network architecture Recommendation for neither conventional
connection type networks nor connectionless typenetworks. Moreover, Q.12 intends to maintain ASON
architecture Recommendation G.8080.
Q.13 is switching its focus from conventional timesynchronous technologies to transmission technology for time synchronization signaling by packet
frames (TDM over packet). It is discussing and creating Recommendations for TDM-over-packet technologies to meet the expected increase in IP signal
traffic, such as Ethernet and MPLS.
Q.14 is discussing and examining Recommendations for network management and control technologies. For ASON, it has switched its focus from signaling on the control plane to relationships on themanagement plane handling transmission equipment
and networks. It has completed a Recommendation
for ASON management framework on the control
plane (G.7718) and is discussing the framework indetail so as to create related Recommendations.
Moreover, Q.14 plans to create Recommendations for
ASON routing as G.7715 series.
References[1][2]

http://www.itu.int/ITU-T/studygroups/com15/structure.html
Y. Hiramatsu and H. Iwata, “Results of ITU-T WTSA-04,” NTT
Technical Review, Vol. 3, No. 4, pp. 44-48, 2005.

NTT Technical Review

Global Standardization Activities

Yoichi Maeda
Senior Manager, Optical Access Systems Project, NTT Access Network Service Systems Laboratories.
He received the B.E. and M.E. degrees in electronic engineering from Shizuoka University,
Shizuoka in 1976 and 1978, respectively. Sincejoining Nippon Telegraph and Telephone Public
Corporation (now NTT) in 1980, he has been
engaged in R&D of access network transport systems for broadband communications, including
synchronous digital hierarchy, asynchronoustransfer mode, and Internet protocol. From 1988
to 1989, he was an Exchange Research Engineer
at British Telecom Research Laboratories, United Kingdom. He currently leads the Global Strategy and the Full Service Access Groups in theOptical Access Systems Project of NTT Access Network Service Systems Laboratories, Chiba, Japan. Since 1989, he has been an active participant in ITU-T StudyGroups 13 and 15, and he served as vice-chairman of ITU-T SG13, chairman ofWP3 of ITU-T SG13, and chairman of OAN WG (Optical Access Network Working Group) of FSAN (Full Service Access Network) from 2001 to 2004. He is serving as chairman of ITU-T SG15 for the 2005–2008 study period. He has written several publications on B-ISDN standards, including Introduction to ATM Networksand B-ISDN (Wiley, New York, 1997). He is a member of the Institution of Electronics, Information and Communication Engineers (IEICE) of Japan. He is a feature editor on standards of IEEE Communications Magazine.

Kenji Nakanishi
Senior Research Engineer, Optical Access Systems Project, NTT Access Network Service Systems Laboratories.
He received the B.E. and M.E. degrees in physical engineering from Kyoto University, Kyoto
in 1983 and 1985, respectively. He joined NTTin 1985. He studied coherent optical transmission
systems including multi-valued FSK modulationand demodulation and dense WDM systems
from 1985 to 1992. From 1992 to 1995, heworked in the Intellectual Property Center. From1995, he was engaged in R&D of passive opticalnetworks (PONs). Since 1997, he has been
engaged in standardization of optical broadband
access networks including PON. Since 1999, hehas been an active participant in ITU-T Study
Groups 4 and 15 and was chairman of OAM WG(Operation And Management Working Group)of FSAN from 1999 to 2001. He is a member ofIEICE.

Vol. 3 No. 6 June 2005

Makoto Murakami
Senior Research Engineer, NTT Network Service Systems Laboratories.
He received the M.E. degree in electrical engineering from the University of Tokyo, Tokyo in1988. He joined NTT the same year and engaged
in R&D of long-haul optically amplified transmission systems and submarine cable systems.
From 2001 to 2003, he worked on the construction of international submarine cable network
systems at NTT Communications. Currently, heis involved in R&D of optical network systems atNTT Network Service Systems Laboratories. He
is a member of IEICE.

Hiroshi Ohta
Senior Research Engineer, NTT Network Service Systems Laboratories.
He received the B.E. degree in electrical engineering and the M.E. and Ph.D. degrees in electronics engineering from Kyoto University,
Kyoto in 1985, 1987, and 2000, respectively. He
joined NTT Electrical Communication Laboratories, Kanagawa, Japan in 1987. From 1987 to1999 he was engaged in R&D of ATM-basedtransport systems, especially optical subscriber
loops, cell loss analysis, cell loss recovery, OAM
functions, and protection switching as well as thedevelopment of an ATM cross-connect system.
Since 2000, he has been engaged in the development of services for corporate users such as IPVPN and metro Ethernet services and services
for consumers such as content delivery services.
Since 1992, he has actively participated in standardization meetings in ITU-T SG13, SG15,IEEE 802, and IETF. He is a rapporteur for Question 3/15 (General characteristics of opticaltransport networks) of ITU-T SG15. He is amember of the IEEE Communications Society
and IEICE.

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