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ITU-T Study Group 15 executive summary

22 June-3 July 2015
ITU-T Study Group 15
Networks, Technologies and Infrastructures for Transport, Access and Home
Study Group 15 Chairman: Stephen Trowbridge

Study Group 15 held its fourth meeting of the 2013-2016 study period in Geneva from 22 June-3 July 2015, attended by 282 delegates representing 33 countries.

The meeting received 329 contributions and 456 TDs, a slight decrease from the previous meeting. The meeting observed the 12-day contribution deadline of revised Recommendation ITU-T A.1, and nearly all of the contributions to this meeting were submitted using Direct Document Posting (DDP).

SG15 approved three revised Recommendations, determined one amendment, and consented 40 texts (five new Recommendations, eleven revised Recommendations, 18 amendments, and six corrigenda). Agreement was reached on one amendment, four new Supplements, and a Technical Paper.

SG15 authorized 15 interim Rapporteur group meetings to be held prior to the next SG15 plenary, 17 virtual meetings, and generated 41 liaison statements.

The next plenary meeting of SG15 will be held 15-26 February 2016 in Geneva.

In fulfilling its lead study group responsibilities, SG15 revised the Access Network Transport (ANT)standards overview and work plan, revised the Optical Transport Networks andTechnologies (OTNT) standardization work plan, revised the Smart Grid standardsoverview and work plan, and revised the Home Network Transport (HNT) StandardsOverview and Work Plan.

During this meeting, SG15 began the process of preparing for WTSA-2016, developing initial draft updates of question texts and updates to the responsibilities and mandates of SG15 as specified in WTSA Resolution 2.


Executive reports from WP Chairmen

WP1/15 – Transport aspects of access, home and smart grid networks
WP1 Chairman: Tom Starr

Q1/15 produced new versions of the Access Network Transport (ANT) Standards Overview and Work Plan documents. The Home Network Transport (HNT) Standards Overview and Work Plan document was revised. The list of CIT activities in other organizations related to technologies based on Recommendations from WP1/15 was updated. Q1 started work to improve the practicability of the ANT Standards Overview format by replacing the manual method with a web-based method.
Q2/15 worked on Passive Optical Networks (PON). Four documents relating to NGPON2 (ITU-T G.989) and one on WM-PON were prepared for consent and G.sup55 (ex. G.supp.RoF) was prepared for agreement. Two new Recommendation projects were agreed: G.RoF and a fixed symmetric 10Gb/s PON (G.XGS-PON).

Q4/15 focused on ITU-T, VDSL2 and the related PLOAM Recommendations, producing amendments and corrigenda for consent. A new VDSL2 profile providing higher bit rates was created. Joint work with Q18/15 produced the new Recommendation ITU-T G.dpm (ITU-T G.9977 mitigation of interference between DSL and PLC systems) and on the Technical Paper.

Q15/15 worked on Smart Grid Recommendations for consent/determination producing an amendment to ITU-T G.9903 for consent. A Supplement G.sup57 based on the G.shp6 Draft, and outgoing liaisons were agreed.

Q18/15 provided three ITU-T Recommendations for approval. Amendments and Corrigenda for the ITU-T series were prepared for consent and determination. Joint sessions with Q4/15 were held to finalize ITU-T G.9977 (ex. G.dpm) and the Technical Paper. A joint session with Q2/15 was held where it was decided to start a new effort on Visible Light Communication (VLC) systems.


WP2/15 – Optical technologies and physical infrastructures
WP2 Chairman: Francesco Montalti

Q5/15: The revised Recommendation ITU-T G.650.2 was consented. Progress was made on the revisions of ITU-T G.652, ITU-T G.654 and ITU-T G.657. In particular for ITU-T G.652 and ITU-T G.657 it was agreed to tighten the MFD existing specifications.

The possibility of introducing a differentiated ITU-T G.652 offering in order to ensure next generation metro, regional, and long haul networks at higher bit rates and different transmission strategies such as DPQSK with coherent detection looking to accommodate economic and technical challenges was discussed. At this time, Q5/15 experts remain divided on the necessity for including a new category/sub-category, and plan to continue active discussion on this topic, taking also into account the view of operators.

Progress was also made on the revision of ITU-T G.654 for terrestrial applications and it was agreed to conduct a chromatic dispersion survey following with the discussion on MFD, cutoff wavelength, and macrobending loss.

Q5 will continue the correspondence activity on fibre Recommendations ITU-T G.652, ITU-T G.657, ITU-T G.654 and ITU-T G.650.3 towards a consent at September 2016 SG15 meeting.

The revised Supplement G.Sup.40 and the new Supplement G.Sup.fcr are also expected for agreement at September 2016 SG15 meeting.

Q6/15: Progress was made on the revision of ITU-T G.959.1, ITU-T G.697, ITU-T G.698.2, ITU-T G.metro, G.Sup39.

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.

  • Low-cost metro applications on the basis of port-agnostic endpoints in draft Recommendation ITU-T G.metro.

Q7/15: A base text of the new Recommendation ITU-T L.fmc, harmonized it with the related IEC standards was discussed. Correspondence activity will continue in view of consent at September 2016 meeting.

Regarding the revision of ITU-T G.671, contributions are invited to enhance the text and parameter definitions to allow for flexible grid applications and for adding new optical components that are especially used for optical interfaces using advanced modulation formats in order to support Q6/15 activities on 40G and 100G application codes. In respect to ITU-T G.672, contributions with specific text proposals about enhancements towards flexible grid technology are invited for future meetings.

Further contributions on a revision of ITU-T G.663 in respect to adding description of XPolM effect are invited.

Q8/15: Progress was made on the revision of the relevant Recommendations considering 100 G applications. The highest priority is to revise ITU-T G.973 considering 100 G applications for submarine systems, which is expected to consent at September 2016 meeting.

The Recommendations ITU-T G.971, ITU-T G.972 and ITU-T G.979 are expected to consent at September 2016 meeting.

Q16/15: Recommendations ITU-T L.10, ITU-T L.26 and ITU-T L.43, has been consented. The texts are harmonized with the relevant IEC normative texts.

Recommendation ITU-T L.59 Amendment 1: “New Appendix IV - Low friction indoor cable and wiring (Japanese experience)” was agreed.

The activities on the new Recommendations ITU-T L.oxcon and ITU-T L.pneid and on the revision of Recommendations ITU-T L.57, ITU-T L.59, ITU-T L.60 and ITU-T L.79 will be carried out by correspondence.

A.1 justification for proposed draft new Recommendations ITU-T L.dsa and ITU-T L.cci were prepared; contributions are expected by correspondence.

Q17/15: New Recommendation ITU-T L.94 (ex L.gpsm) and revised Recommendation ITU-T L.25 were agreed for consent.

Question 17/15 will prepare draft for the new Recommendations ITU-T L.nrr-frm and ITU-T related to disaster management and recovery.

A new work item for Recommendation ITU-T L.wdc was initiated: contributions are expected by correspondence.

WP2 issued the Technical Report “Optical Fibres, Cables and Systems”, as revision of the existing Handbook dated 2009.

A revision of the classification of the ITU-T L.series Recommendations by technical area instead than chronologically has been discussed and will be implemented by correspondence.


WP3/15 – Transport network characteristics
WP3 Chairman: Ghani Abbas

In fulfilling its Optical Technology and Optical Transport Network coordination role, WP3/15 updated the Optical Transport Networks & Technologies (OTNT) Standardization Work Plan.

Considerable progress was made on a number of transport network technology fronts, including OTN beyond 100G, SDN for Transport networks, OTN and Ethernet protection, Ethernet OAM and Equipment specifications for Packet based Transport Networks, transport network architecture, time and frequency transport, generic and technology-specific transport equipment management requirements, information models and the application of SDN to transport networks.

In the area of network restoration and protection WP3 has revised Recommendations ITU-T G.873.2 “OTN shared ring protection”, ITU-T G.8032 “Ethernet Ring Protection” and produced a new Supplement G.suppl.54 where Ethernet linear protection Recommendation ITU-T G.8031 is applied to PON. WP3 has progressed the work on ODU shared mesh protection (ODU SMP) and Multi-domain Segmented Protection (MDSP).

In the area of interfaces, OAM and packet equipment, WP3 has revised Recommendations ITU-T G.8013 “OAM functions and mechanisms for Ethernet based networks”, ITU-T G.8113.2 “Operations, administration and maintenance mechanisms for MPLS-TP networks using the tools defined for MPLS” and ITU-T G.8112 “Interfaces for the MPLS Transport Profile (MPLS-TP) layer network”. Additionally, WP3 has consented a corrigendum to Recommendation ITU-T G.8021 “Characteristics of Ethernet Transport Network Equipment Functional Blocks”. WP3 also progressed the work on Ethernet and MPLS-TP OAM and equipment.

In the area of Optical Transport Network (OTN), progress was made on B100G where working assumptions and LLs were updated. Additionally, a Supplement G.suppl.56 “OTN Transport of CPRI signals” was agreed. A corrigendum to Recommendation ITU-T G.798 “Characteristics of optical transport network hierarchy equipment functional blocks” was also consented.

Considerable progress was made on Transport SDN architecture, Common Control Aspects, transport of Synchronization over OTN, Flexible Ethernet mapping and Flexible OTN interfaces.

Significant progress was also made on transport of frequency, time and phase over packet networks, where it was agreed to consent the following:

  • Recommendation ITU-T G.8260 “Definitions and terminology for synchronization in packet networks”

  • Amendments to Recommendations ITU-T G.8273 “Framework of phase and time clocks”, and ITU-T G.8273.2 “Timing characteristics of telecom boundary clocks and telecom time slave clocks”

  • A corrigendum to ITU-T G.824 “The control of jitter and wander within digital networks which are based on the 1544 kbit/s hierarchy”

A new work item was initiated addressing “Synchronization Layer Functions for packet-based networks”.

In the area of Management and control of transport systems and equipment, the following texts were consented:

  • New Recommendation ITU-T G.7711 “Generic protocol-neutral management Information Model for transport resources”

  • Revision of Recommendation ITU-T G.8051 “Management aspects of the Ethernet Transport (ET) capable network element ”

  • Amendments to Recommendation ITU-T G.874” Management aspects of optical transport network elements”, Recommendation ITU-T G.874.1 “Optical transport network (OTN): Protocol-neutral management information model for the network element view” and Recommendation ITU-T G.7712 “Architecture and specification of data communication network”

Good progress was made on the management of synchronization, use of SDN for protection and restoration, and for MPLS-TP the NE Management Requirements and the information model.

The latest SG15 Rapporteur meeting plan is at:

The latest Status of Recommendations is reflected in the Work Programme at:    

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