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Meeting Executive Summary

14 – 25 February 2011
Study Group 15 Chairman: Yoichi Maeda

Overview of the fourth Study Group 15 meeting of the 2009-2012 study period

Geneva, 25 February 2011, the plenary meeting of the fourth Study Group 15 of the study period 2009-2012 drew to a close with a total of 44 draft new and revised texts including 3 determined Recommendations, 36 draft consented texts and 7 agreed texts. 345 delegates represented 26 countries with 408 Contributions and 474 Temporary Documents. These figures were similar to the last SG15 meeting in June 2010.

The meeting continued to use the experimental 12-day submission deadline for contributions. In the closing plenary on 25 February, audio casting was provided for the first time in SG15 as an experimental trial to enable the meeting to be followed remotely; the archived audio files can be found at: 

Study Group 15 is the focal point in ITU-T for the development of standards on optical transport networks and access network infrastructures, systems, equipment, optical fibres and cables, and their related installation, maintenance, test, instrumentation and measurement techniques, and control plane technologies to enable the evolution toward intelligent transport networks. This encompasses the development of related standards for the customer premises, access, metropolitan and long-haul sections of communication networks.

The meeting approved SG15’s appointments, including the appointment of new Rapporteurs, Liaison Rapporteurs and Editors, as follows:

The updated study group structure can be found at

The updated list of the SG15’s management members can be found at

The updated list of Rapporteurs for the Questions can be found at

The updated list of appointed Editors of Recommendations can be found in Work Programme at

The updated list of appointed Liaison Rapporteurs can be found at

The meeting progressed work on Questions related to the key areas: optical and metallic access networks; optical transport network technology and structure. The meeting progressed Lead Study Group studies on Access Network Transport, Optical technologies and Optical Transport Networks. The meeting also reviewed and updated the SG15 work programme and discussed Liaison Statements from/to other groups including IEC, IETF, OIF, MEF, TM Forum, Broadband Forum and IEEE to harmonize the work with the relevant bodies.

For the first time in this study period, SG15 decided to progress Recommendations ITU-T G.9955, G.9980 and G.8113.1 under the Traditional Approval Process. The key progress made in this SG15 meeting includes the ITU-T G.9955 and G.9956 (ex. G.hnem) standards providing the physical layer specification and the data link layer specification for narrowband OFDM power line communications transceivers over frequencies below 500 kHz, and the standards on Multiprotocol Label Switching deployment in transport networks (MPLS-TP).

Regarding MPLS-TP, much effort was made to reach a compromise over the last three years and during this SG15 meeting but the decision was taken very exceptionally by vote, since all attempts at compromise had failed. The meeting agreed first stage approval of key new standards which will give network operators the tools necessary to manage large scale deployments of MPLS-based transport networks. Network operators will now have a choice of operations, administration and maintenance (OAM) tools that meet their specific transport network requirements.
The vote passed the package of decisions known as option delta with one amendment made during the meeting to use TAP instead of AAP for G.8113.1 (ex. G.tpoam).

Option Delta as amended by the meeting

  • ITU-T decides to address needs of TD522/WP3 operator environment not satisfied by IETF solutions in ITU-T Recommendations.
  • Consent/determine two documents which have complete content at this meeting, with approval contingent on the codepoint assignment requested in draft-tsb (TD512/WP3)
    • Consent G.8110.1 (TD395/PLEN + interconnection Appendix 1 from C.1124, applicability statement from TD522/WP3)
    • Determine G.8113.1 (ex. G.tpoam, TD377/PLEN + applicability statement from TD522/WP3)
  • Interim meeting week of 5-9 September 2011 to progress/complete work on G.8101, G.8112, G.8113.2 (pending completion of RFCs); G.8121, G.8131[.1/2], G.8132[.1], G.8151 in December
  • Update draft-tsb to include scope statement from TD522/WP3.
  • Send liaison statement to IETF (draft in Annex D/ TD458/PLEN) for action requesting advancement of draft-tsb to achieve the assignment of a G-ACh codepoint.
  • Send liaison statement For Information to IETF (draft in Annex E/ TD458/PLEN) with consented and determined texts

A contribution was received from ISOC (C-1445), entitled “Adherence to In-Force Cooperation Agreements for the Development of MPLS-TP OAM Solutions”. The SG15 Chairman clarified PP-10 Resolution 101 on Internet Protocol-based networks after consultation with TSB, see TD460/PLEN.

The networking event in SG15 was successfully organized with the support of Corning, USA, and attracted a lot of participation on 17 February 2011. It was agreed that another networking event will be held at the next SG15 meeting to facilitate communication and networking amongst participants of the different Questions.

Executive reports from WP chairmen and SG15’s promotion coordinators

Working Party 1/15 - Transport aspects of access networks and home networking
WP1 Chairman: Tom Starr

WP1/15 produced one Recommendation for approval, 16 Recommendations for consent, one text for agreement, and 16 liaisons to be sent by SG15.  The decisions taken during the closing SG15 Plenary resulted in ITU-T G.9955 and ITU-T G.9980 proceeding under the Traditional Approval Process.  The ITU-T G.9960 corrigenda and amendment were removed from the list of Recommendations for approval at this time.

Q1/15 met for two days, including a joint session with Q2 and Q4/15.  ITU-T G.phnt (ex. G.cmhn) was revised and issued as TD/WP1 458 Rev.2 for circulation to appropriate SDOs by oLS.  New issues of the ANTS Overview and Work Plan were prepared based on iLS and expert input and are provided to WP1/15 and SG15 as TD/PLEN 436 and TD/PLEN 437 for approval, and were posted on the ANT web page.

Q2/15 met for two days.  The meeting agreed Amendment 1 to the generic OMCI Recommendation, ITU-T G.988.  Supplement 49 to G-series Recommendations (ex. G.sup.rogueONU) was agreed.  A liaison to the IEEE P1904.1 group was prepared.  Continuing work will include improvements to the XG-PON series (e.g., ITU-T, as well as maintenance.

Q4/15 met for nine days with much of the time devoted to preparing ITU-T G.9955, ITU-T G.9956, ITU-T G.9960, ITU-T G.9961, ITU-T G.993.2 and ITU-T G.998.4 for consent. Work also progressed on the others DSL Recommendations.  It was decided to start two new projects: ITU-T G.wnb (Wireless Narrow Band) regarding wireless narrowband transceivers for home networking; and ITU-T for a very high data rate solution for very short copper access loops.  A liaison to the ITU-R was approved seeking to establish a collaborative relationship with SG15 for addressing ITU-T G.wnb.

In addition to interim rapporteur meetings planned for the next several months, an interim WP1/15 meeting was planned for the afternoon of 16 September 2011 to be held in Geneva, Switzerland.  The objectives for this meeting are to progress the work from Q1/15 and Q4/15 on the home networking and DSL Recommendations with possible consent or agreement of related texts.

Working Party 2/15 - Optical access/transport network technologies and physical infrastructures
Acting WP2/15 Chairman: Viktor Katok (WP2/15 Chairman: Francesco Montalti)

WP2/15 prepared one new and four revised Recommendations for consent. One appendix, one amendment, one corrigendum of existing Recommendations and one revised G-series Supplement were proposed for agreement. One L-series Recommendation was proposed for deletion, and seven L-series Recommendations were proposed for transferring to SG5.

Moreover, one questionnaire was proposed for agreement, in order to gather information and technical considerations from Members on the use of GPS (global positioning system) to create a referenced network map. Responses to this Questionnaire will be used for the drafting of new Recommendation ITU-T L.gpsm

A draft of the “Guide on the use of ITU-T L-series Recommendations related to Optical Infrastructures” was prepared. 

Q18/15 progressed the draft of ITU-T L.oanbs - intended to describe the different aspects necessary for the design and construction of an optical access network to be used in fibre-to-the-home (FTTH) applications – while it was decided that the material gathered for the drafting of ITU-T L.socnbs (detailed description of the requirement of components to be used in optical access networks for broadband services) will be used instead as an appendix of ITU-T L.oanbs.

A flyer related to the construction of infrastructures has been prepared.

Among the future activities are:

  • New Recommendation ITU-T L.cna, “Optical fibre cable constructions for a new application” was marked as a high priority. It was pointed out that riser, high-density micro-cable and indoor/outdoor cables are candidates for new applications. 
  • New Recommendation ITU-T L.dmops ,“Disaster managements for outside plant facilities”.
  • New Recommendation ITU-T G.msub, “Characteristics of monitoring systems for optical submarine cable systems”.
  • New Recommendation ITU-T L.coi, “Solutions for outdoor installation of ducts and cables in an occupied infrastructure”.
  • New Recommendation ITU-T G.sdapp, which provides optical interface specifications towards the realization of transversely compatible seeded dense wavelength division multiplexing (DWDM) systems primarily intended for metro applications.
  • New Recommendation ITU-T G.rmon, dealing with Reconfigurable Multi-Degree Optical Nodes. 
  • Revision of Recommendation ITU-T G.654, enlarged mode field diameter (MFD), reduced attenuation coefficient and relaxed chromatic dispersion will be discussed to support future high speed and long-distance optical submarine systems. 
  • Revision of Recommendation ITU-T G.698.2, establishing sets of parameters and associated values to enable multi-vendor interoperability for 40 Gbit/s application codes with various modulation formats.  
  • Regarding ITU-T G.657 fibres: investigation of the compatibility among different technologies; reliability issues; and the possibility to create new categories for bend insensitive fibres. 

Working Party 3/15 –Transport network structures
WP3 Chairman: Stephen J Trowbridge

WP3/15 prepared one new Recommendation for determination and seven revised Recommendations for consent, together with eight amendments and three corrigenda. A new appendix and a revised supplement were prepared for agreement.

In fulfilling its Optical Technology and Optical Transport Network co-ordination role, WP3/15 updated the Optical and other Transport Networks & Technologies Standardization Work Plan (Issue 14), which is available at:

Continuing the work of the evolution of the Optical Transport Network hierarchy begun in 2009 with the major revision of ITU-T G.709, updates were made to the OTN Equipment specifications (ITU-T G.798) including clarifications to the mappings for IEEE 40GBASE-R and 100GBASE-R client signals. A new Recommendation was prepared on OTN equipment types (ITU-T G.798.1). An amendment was prepared to ITU-T G.709 to include mappings for InfiniBand client signals and to produce a set of recommended bit rates for ODUflex(GFP) to ensure that a common set of rates are supported across multiple vendors. The OTN linear protection Recommendation (ITU-T G.873.1) was revised, and progress was made toward development of an OTN ring protection Recommendation. The OTN error performance document (ITU-T G.8201) was revised to incorporate the new signal rates added in the 2009 revision of ITU-T G.709. The Recommendation on OTN jitter and wander performance (ITU-T G.8251) was amended to include specifications for the multi-lane OTU3 and OTU4 IrDI interfaces based on Ethernet optics. A correction was made to the OTN management Recommendation (ITU-T G.874). The supplement on mapping of IEEE 10GBASE-R signals into OTN was revised (ITU-T G.sup43). Significant progress was made on a new Recommendation for hitless resizing of ODUflex(GFP) signals, with the finalization of the technical aspects expected to be completed at the interim meeting of Q11/15 in May 2011.

Work was progressed on Ethernet over Transport Recommendations, with a revision to the terminology Recommendation (ITU-T G.8001), an amendment to the equipment specifications (ITU-T G.8021), a revision of the OAM Recommendation (ITU-T G.8013/Y.1731), an amendment to the management Recommendation (ITU-T G.8051), and an amendment to the test equipment specification for Synchronous Ethernet (ITU-T O.174). A revised Appendix – End to End Service Resilience – was produced for the Ethernet Ring Protection Recommendation (ITU-T G.8032).

In the area of MPLS-TP, WP3/15 continued its efforts to find a way forward with the goal of finding an approach to OAM that would satisfy the broad range of stakeholders. After several failed attempts at compromise during the meeting, the SG15 closing plenary decided on an historic Member State vote to consent a revision to the MPLS-TP architecture Recommendation (ITU-T G.8110.1) and to determine a new Recommendation documenting OAM based on ITU-T Y.1731 for MPLS-TP networks (ITU-T G.8113.1). This would be in conjunction with an expected additional Recommendation  (ITU-T G.8113.2) to document OAM based on the IETF-defined toolset (e.g., CC-CV-RDI based on BFD) once the necessary RFCs have been published.

Other work completed included a revision to the Generic Framing Procedure (GFP) Recommendation (ITU-T G.7041) for the mapping of packet and other traffic into CBR transport layers, an amendment to the generic equipment model (ITU-T G.806), and a correction to the common equipment management requirements (ITU-T G.7710). An amendment was prepared to the Precision Time Protocol (PTP) telecom profile for frequency synchronization (ITU-T G.8265.1).

Work was progressed in many other areas under the responsibility of WP3/15, including additional OTN clients, Ethernet services, Ethernet UNI and NNI, architecture, management and control, and transport of frequency, phase and time over packet networks.

Innovation and Marketing SG15 Executive Summary for February 2011 meeting
Innovation and Marketing coordinator: Helmut Schink

SG15 has been successfully represented in a number of conferences on cables and fibres, synchronization, optical transport, packet networks and fibre-to-the-home. At the FTTH Council Europe a half day tutorial session was held.

The new manual on optical transport was finished and a manual on broadband access started.

SG15 participation in Telecom World 2011 (TW11) is under discussion, as well as ITU driven interoperability events on SG15 Recommendations.

SG15 public relations coordination
SG15 public relations coordinator: Shaohua Yu

SG15 received 15 Liaison Rapporteur’s reports reflecting the highlights of other SDO’s activities (EWM, IEC TC86 SC86A/SC86B/SC86C, TMN Project Management, IETF on TNM, TM Forum on MTNM issues, IETF for Routing Issues, OIF for control plane topics, OIF PLL, IEEE P802.3bg, MEF, IEEE 802.1, IEEE 802.3, IEEE 802.17) and proposed the two hot topics for promotion from consented/determined texts on ITU-T G.9955 (G.hnem) -  narrowband home networking transceivers - and ITU-T G.798.1 - Types and Characteristics of Optical Transport Network (OTN) Equipment. 92 incoming Liaison Statements were received as input from other SDOs, and the 36 new outgoing LSs were produced at this plenary meeting. SG15 has nominated 15 Liaison Rapporteurs to take part in other SDO’s activities and prepare reports for the next SG15 meeting.

With reference to the content of the WTSA-08 Resolution 44, SG15 has completed the manual “Optical Transport Networks from TDM to Packet” and is now preparing to draft a new manual on “Copper/optical broadband access networks and home networking”. These manuals could be used by developing countries when upgrading their optical transport networks and systems to meet their requirements.



Executive summary, 31 May - 11 June 2010