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Meeting Executive Summary

10-21 September 2012

Study Group 15

Optical transport networks and access network infrastructures

Study Group 15 Chairman: Yoichi Maeda


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

Geneva, 21 September 2012, the plenary meeting of the seventh and last Study Group 15 meeting of the 2009-2012 study period drew to a close with a total of 56 draft new and revised texts including one TAP Approved Recommendation, three AAP Approved Recommendations, two Determined Recommendations, 46 draft Consented texts, and four agreed texts. It also included the agreements to submit three draft Recommendations to WTSA and to send 31 outgoing Liaison Statements.

The two Determined draft Recommendations (ITU-T G.8113.2/Y.1372.2 and ITU-T G.9901) were Determined and sent to WTSA-12 for Approval. In addition, the meeting endorsed the Chairman's decision to send one draft Recommendation to WTSA-12 (ITU-T G.9980) due to previous failures to Approve. The meeting noted that ITU-T G.8113.1/Y.1372.1 had already been sent to WTSA-12, which brings the total sent to WTSA to four.

The meeting was attended by 381 delegates represented 17 countries, and received 438 Contributions and 455 TDs. These figures were similar to the last SG15 meeting in December 2011.

The meeting used the experimental 12-day submission deadline for Contributions with Direct Document Posting system accounting for around 91% of submissions. During the opening and closing plenary sessions on 10 and 21 September, audio casting was provided in English, Chinese, French and Russian 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 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. The meeting proposed draft new SG15 Question texts for consideration at WTSA-12.

The meeting approved SG15’s appointments, including the appointment of Rapporteurs, Liaison Rapporteurs and Editors, and also agreed to merge Q15/15 into Q13/15 and to merge Q18/15 into Q16/15.


The in-force 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 the ITU-T work programme at:



The updated list of appointed Liaison Rapporteurs can be found at


Key outcomes at study-group level include:
  1. ITU-T G.9980 – at the opening Plenary session on 10 September 2012 the meeting endorsed the Chairman's decision send ITU-T G.9980 to WTSA-12 (Document 41) following failures to Approve the draft text due to non-technical reasons. The SG15 Chairman, in consultation with the Director of TSB, deferred discussion on this Determined text to WTSA-12 according to Resolution 1, section 9.2.2c. After seeking the permission of the meeting to accept further discussion on a compromise Contribution from Germany, this was referred to Q2/15 for consideration by the experts with the possibility of Determining a new compromise text. Unfortunately, no compromise solution was reached and the Determined text that had been submitted to WTSA-12 remained as it is, as a SG15 meeting agreement. Since no compromise was reached, Germany requested that their statement be recorded in the meeting report.
  2. Determined new Recommendation ITU-T G.9901 (revised ITU-T G.9955) was agreed to be sent to WTSA-12 to accelerate the Approval to meet market demand. The meeting confirmed the text of ITU-T G.9901 was technically stable, constituting an editorial remapping of existing Approved content and there is no new/additional technical material.
  3. Regarding the issue on “Precedence text”, which is the statement on the relationship between ITU-T MPLS-TP Recommendations and the IETF RFCs that they normatively reference, the meeting reached an agreement to revert to the relationship text agreed for Recommendation ITU-T G.8110.1 at the December 2011 meeting.  The resolution is that the following text should be used in all MPLS-TP Recommendations that make normative references to IETF RFCs, unless and until SG15 receives a response from TSAG with alternative text: “This Recommendation provides a representation of the MPLS-TP technology using the methodologies that have been used for other transport technologies (e.g. SDH, OTN and Ethernet).” With the following footnote: “This ITU-T Recommendation is intended to be aligned with the IETF MPLS RFCs normatively referenced by this Recommendation.” Also the following agreements should be included: “All MPLS-TP Recommendations that make normative references to IETF RFCs will use the same text. These Recommendations should be aligned at the earliest opportunity. If an MPLS-TP Recommendation does not make a normative reference to an IETF RFC then the text will not be used in that Recommendation.”
  4. Regarding the approval of the Recommendations that were referred back to SG meeting under AAP, the meeting reached agreements on the Approvals of ITU-T G.9961 (2010) Amd. 1 and ITU-T G.9956 (2011) Cor.1 from WP1/15 and revised ITU-T G.8121/Y.1381 from WP3/15. 
  5. Determined ITU-T G.8113.2 was agreed to be sent to WTSA. The request was proposed by a contribution from Canada. The proposal was supported by USA, UK and France and agreed by the meeting without any objection. As the result of the agreements in this and last SG15 meetings, the meeting recommends both Recommendations ITU-T G.8113.1/Y.1372.2 and ITU-T G.8113.2/Y.1372.2 are sent to WTSA-12 for Approval.
  6. The meeting agreed the texts for SG15’s Part 2 report to WTSA-12, which proposes updated Question texts for the next study period. The proposal includes merging Q15/15 into Q13/15 and Q18/15 into Q16/15. Also SG15’s new title for the next study period was agreed for proposal to WTSA-12 as:“Networks, Technologies and Infrastructures for Transport, Access and Home”.
  7. An interim WP1/15 meeting is agreed to be held on 1 February 2013 at the ITU premises in Geneva to progress work on Recommendations related to customer premises and home networking.
  8. A networking event, supported by DSM (Netherlands) and NTT (Japan) was a great success on 13 September 2012. The meeting supports the continuation of networking events in the next study period to encourage human networking in SG15.



Executive reports from WP chairmen and SG15’s promotion coordinators


Innovation and Marketing SG15 Executive Summary; Innovation and Marketing coordinator: Helmut Schink

SG15 has been represented in a number of conferences on synchronization, optical transport, packet networks, and a plan for the coming months is revised as well as flyers updated.

Conformance and interoperability has been discussed based on the decisions made by Council in July 2012. SG15 is one of the SGs with the most active development of Recommendations aiming at interoperability and is already very active in the development of interoperability and conformance tests and specifications jointly with other organisations like BBF, HGF and MEF. Experts have been asked to discuss within the questions the market need for additional CIT related work to further enhance the quality of the outcome and TSB offered support for the implementation.


Working Party 1/15 - Transport aspects of Access networks and home networking

WP1/15 Chairman: Tom Starr

WP1/15 met from 10 to 20 September 2012 in Geneva, Switzerland.  An interim WP1/15 meeting will be held on 1 February 2013 in Geneva, Switzerland to address consent of Recommendations in the ITU-T G.996x series, and other matters as needed.


Q1/15 met on 19 September 2012.  The ANT Standards Overview and Work Plan were revised and new versions were produced.  The Q1/15 experts revised the Question 1 Terms of Reference. Question 1 proposes to assemble a database of Home Network transport standards similar to the ANTS in the 2013-2016 study period.


Q2/15 met on 10-13 September 2012.  Major topics of the meeting were G.ngpon2, G.988 revision, G.987- and G.984- series maintenance, G.epon, G.9980 and G.multi.  Joint meetings were held with Q4a/15, Q6/15 and Q12/15.  Also, Q2/15 hosted a representative from the European Commission who spoke about the regulatory framework in the European Union. 


Q4a/15 met for nine days and addressed 60 contributions. Five Recommendations had amendments for Consent at this S15 meeting. DSL progressed on the VDSL2 European Band Plans and PSD masks and on the upstream frequency-dependent pilot sequences for vectoring. has reached consensus on the Forward Error Correction (FEC) method to be used.


Q4b/15 met for seven days with much of the time devoted to progressing the work on corrigenda and amendments to ITU-T G.9960 and ITU-T G.9961.


Q4c/15 met for five days with much of the time devoted to preparing G.9955 (2011) Amd.1 and ITU-T G.9956 (2011) Cor.1 for Approval, and also for completing the editorial restructuring of these texts into four new Recommendations (ITU-T G.9901, ITU-T G.9902, ITU-T G.9903 and ITU-T G.9904).


Three draft new Recommendations were agreed for forwarding to the SG15 plenary for Consent. Two draft revised Recommendations was agreed for forwarding to the SG15 plenary for Consent. Six draft amendments and corrigenda to existing Recommendations were agreed for forwarding to the SG15 plenary for Consent. Three Recommendations were sent to the SG15 plenary for Approval. Thirteen draft Liaison Statements were prepared, and 25 interim Rapporteurs’ meetings and teleconferences were planned.


Working Party 2/15 - Optical access/transport network technologies and physical infrastructures

WP2/15 Chairman: Francesco Montalti

WP2/15 prepared three new and four revised Recommendations and one amendment for Consent. WP3/15 also prepared one new and one revised flyer for agreement.

Q5/15 proposed two revised Recommendations for consent:

  • ITU-T G.654 proposes a new category of fibres with enhanced characteristics in order to improve the signal-to-noise ratio in submarine applications;
  • ITU-T G.657 addresses the definition of compliance and compatibility to be added to the scope.

The activity on fibres will continue addressing the revision of ITU-T G.652, macrobending characteristics, splicing compatibility and 200 μm coated fibres.

Moreover, the reduction of the range of the fibre MFD was considered: this will benefit the standardization a new family of field-mountable connectors.


Q6/15 proposed ITU-T G.664 for Consent, related to optical safety.

The current highest priority of Q6/15 is to establish sets of parameters and associated values to enable multi-vendor interoperability for the various modulation formats for 40G and 100G application codes in a revision of ITU-T G.698.2 and the study of the potential need of new optical interface specifications for low-cost metro applications on the basis of wavelength-agnostic endpoints.


Q7/15 proposed ITU-T G.672 for Consent, which addresses reconfigurable add-drop multiplexers. Regarding ITU-T G.671 that was consented at the last meeting, the issue of interpretation of optical passive component specifications in IEC and ITU-T was addressed, discussing aspects of BOL versus EOL values, and this will be an item of future attention.

Regarding the passive components for outside plant (L-series Recommendations) Q7/15 will continue to study the characteristics of connectors, splices and splitters, while the other components, such as closures, MDF and cabinets would be transferred to the proposed new Q16/15.


Q8/15 proposed for Consent ITU-T G.979, related to monitoring system for submarine plant. The activity for the next period will be devoted to the update of existing Recommendations on submarine as well as marinized cables.

Q17/15 proposed ITU-T L.92 for Consent, related to “Disaster managements for outside plant facilities” and ITU-T L.64 related to “ID tags for network element identification”. Future studies will continue on items such as “optical fibre cable maintenance support, monitoring and testing system for optical fibre cable networks for trunk lines”, taking into account the existing ITU-T G.697 in order to avoid duplication and on the “Use of GPS (Global Positioning System) to create referenced network maps”.


WP2/15, considering the reduced activity of Q16/15 and Q18/15, proposed to merge them (together with part of Q7/15) into a new Q16/15 “Outside plant and related indoor installation”.


Working Party 3/15 –Transport network structures

WP3/15 Chairman: Stephen J Trowbridge

WP3/15 prepared one revised Recommendation for Approval and one new Recommendation for Determination. WP3/15 prepared six new and 10 revised Recommendations, nine amendments, and two corrigenda for Consent. WP3/15 also prepared a new supplement and a new appendix 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 16).


In the area of Optical Transport Network (OTN), the first major revision of the architecture document ITU-T G.872 was made since 2001, including improved modeling for the photonic media layer and providing terminology and concepts more easily extensible to future flexible grid networks. The OTN equipment Recommendation ITU-T G.798 and terminology Recommendation ITU-T G.870 were revised, and an amendment and corrigendum were prepared to the OTN interfaces in ITU-T G.709. This, together with a revision to the OTN jitter Recommendation ITU-T G.8251 provided appropriate specification for transport of DVB_ASI signals and guidance for transport of CPRI signals. Amendments were prepared to the OTN linear and ring protection Recommendations ITU-T G.873.1 and ITU-T G.873.2. The OTN management Recommendation ITU-T G.874 was amended, and the protocol-neutral management information model ITU-T G.874.1 was revised.


In the area of Ethernet Transport, the Equipment Recommendation ITU-T G.8021 was amended and a new Recommendation ITU-T G.8021.1/Y.1341.1 was prepared on Ethernet Transport equipment types. The overall Ethernet services Recommendation ITU-T G.8011/Y.1307 (based on the MEF Ethernet service definitions) and terminology Recommendation ITU-T G.8001/Y.1354 were revised. A new Supplement 52 was agreed providing examples for Ethernet ring protection switching. An amendment was prepared to Recommendation ITU-T G.8262/Y.1362 on synchronous Ethernet equipment slave clocks.


Additional synchronization work was completed including an amendment to Precision Time Protocol Telecom Profile for frequency synchronization in ITU-T G.8265.1/Y.1365.1, adding the IPv6 mapping option, and a new Recommendation ITU-T G.8272/Y.1367 was completed on a Primary Reference Time Clock.


Work on generic network aspects, a corrigendum was prepared to the generic equipment model in Recommendation ITU-T G.806 and an amendment to the Generic Framing Procedure (GFP) Recommendation ITU-T G.7041/Y.1303 used for mapping of packet layers over circuit layers in a transport network was also produced. A new Recommendation ITU-T G.808.3 was prepared specifying a new generic protection switching approach for shared mesh protection, and a new appendix was added to the generic linear protection switching Recommendation ITU-T G.808.1.


In the area of MPLS-TP, the equipment Recommendation G.8121/Y.1381 was Approved and the OAM Recommendation ITU-T G.8113.2/Y.1372.2 was Determined. Revisions to the interfaces Recommendation ITU-T G.8112/Y.1371 and terminology Recommendation ITU-T G.8101/Y.1355, as well as amendments to the equipment and management Recommendations ITU-T G.8121/Y.1381 and G.8151/Y.1374 were Consented.


A new Recommendation ITU-T O.175 on jitter measuring equipment for XG-PON was produced and Consented.


WP3/15 completed its consideration of Question texts for the 2013-2016 Study Period. WP3/15 intends to merge Q13/15 and Q15/15 and rearrange work among Q9/15, Q10/15 and Q11/15.



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