SG15 Executive Summary - January 2020

27 January-7 February 2020
ITU-T Study Group 15
Networks, Technologies and Infrastructures for Transport, Access and Home

Study Group 15 held its fifth meeting of the 2017-2020 study period in Geneva from 27 January-7 February 2020, attended by 254 delegates representing 30 countries. The outbreak of the coronavirus prevented a number of delegates from attending the meeting. In view of these exceptional and unexpected circumstances remote observation and remote participation were provided for the meetings of some Questions.

The meeting received 425 contributions and 411 TDs, an increase from the previous meeting, and the largest number of contributions received this study period. Q11/15 alone received 140 contributions. 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).

The meeting was preceded in Geneva by interim meetings of the IEEE 802.1 and 802.3 working groups and a joint ITU-T/IEEE workshop on Saturday, 25 January. IEEE 802.3 and Nokia were sponsors of the workshop. The workshop information, including links to all presentations on the “programme" link are available at:
https://www.itu.int/en/ITU-T/Workshops-and-Seminars/202001/Pages/default.aspx

SG15 approved two new Recommendations and three Amendments, consented 39 texts (4 new and 10 revised Recommendations, 16 Amendments, and 9 Corrigenda), and agreed three technical papers/reports, one Amendment, two supplements, and one Implementers' Guide.
SG15 authorized 14 interim face-to-face Rapporteur group meetings to be held prior to the sixth SG15 plenary of the 2017-2020 study period, 17 virtual meetings, and generated 30 liaison statements. The sixth plenary meeting of SG15 in the 2017-2020 study period is scheduled 7-18 September 2020 in Geneva.
In fulfilling its lead study group responsibilities, SG15 revised the Access Network Transport (ANT) standards overview and work plan, the Home Network Transport (HNT) Standards Overview and Work Plan, and the Optical Transport Networks and Technologies (OTNT) standardization work plan. No update was needed to the Smart Grid standards overview and work plan, which no longer requires active coordination.

To improve the efficiency of SG15 work, SG15 has proposed to merge the scope of current Q7/15 into Q6/15, and to merge the scope of current Q15/15 into Q18/15. SG15 developed an initial set of inputs to TSAG regarding WTSA-20 preparation, including draft SG15-related updates to WTSA Resolution 2 (regarding study group responsibility and mandates), and draft text of 13 study questions proposed by SG15 for the 2021-2024 study period.

​Executive reports from WP Chairmen​

WP1/15 – Transport aspects of access, home and smart grid networks
WP1 Chairman: Tom Starr; WP1 Vice-Chairman: Ian Horsley

Q1/15 met for one day, updating 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 certification and interoperability activities for WP1/15 Recommendations was updated.

Q2/15 met for four days, working on Passive Optical Networks (PON), preparing seven texts for consent.  Two new PON project proposals were discussed, without achieving consensus to start work.

Q4/15 met for eight days, working on access via metallic conductors, focusing on G.fast and the next-generation MGfast. One text was prepared for approval and six for consent.

Q18/15 met for five days, working on the G.hn family of Recommendations, Visible Light Communication, and related projects.  A new project started, G.fin addresses networking on fiber within the premises. Six texts were prepared for consent, three for approval, and one Technical Paper for agreement.

The WP1/15 Question texts were reviewed and updated.  Since the level of activity on smart grid has reduced, WP1/15 asks that Q15/15 be merged into Q18/15 and that SG15 no longer be identified as the lead Study Group for smart grid.​WP2/15 – Optical technologies and physical infrastructures

WP2 Chairman: Noriyuki Araki; WP2 Vice-Chairman: Peter Stassar

WP2/15 made good progress on the development of a number of Recommendations and produced one revised Recommendation, one Amendment and one Technical Paper. WP2/15 produced three Liaisons and updated its work programme. WP2/15 also scheduled one interim meeting and a number of correspondence activities to progress the work.
WP2/15 agreed with the merger of Q6/15 and Q7/15 and prepared updated terms of reference for endorsement by TSAG. WP2 also agreed with the WP2/15 restructuring for the next study period (2021 – 2024) as follows;
·       Transfer L.100-series Recommendations (L.100 – L.199) from Q16/15 to Q5/15,
·       Transfer L.400-series Recommendations (L.400 – L.429) from Q7/15 to Q16/15,
·       Merge Q16/15 with Q17/15.

Q5/15 submitted revised G.654 for consent to the SG15 closing plenary meeting, specifying the attenuation coefficient of G.654.E-fibre considering wavelength dependency and made progress on the revision of G.650.1 to clarify the wavelength dependence of the G.654.E fibre by using spectral attenuation modelling. Also, Q5/15 agreed to start a new work item for a Technical Report on optical fibre and cable for space division multiplexing transmission.

Q6/15 made progress on a revision of G.698.2 that considers extensions for 200 and 400 Gbit/s application codes, and new work items to add 25 Gbit/s optical interface specifications to G.698.1, G.698.2 and G.698.4 to address the needs of mobile optimized transport.

Q7/15 made progress on the revision of G.672 towards consent at the next meeting, adding asymmetric group delay. Q7/15 agreed to start a new work item to revise L.400 to add fusion splice insertion loss values taking into account different fibre alignment methods and different fibre types.

Q8/15 made progress on new draft Recommendation G.977.1 and the revisions of G.971 and G.972 that deal with general features and definitions of optical submarine cable systems. Q8/15 also agreed to start a new work item to revise G.sup.41 to add guidelines for fibre identification in submarine cable systems.

Q16/15 continued the work on optical physical infrastructures and submitted an Amendment to L.105 for agreement to the SG15 closing plenary meeting. Q16/15 agreed to start three work items for new Recommendations related to optical fibre cable distribution for FTTx and optical access systems, such as optical/electrical hybrid cables, combined fibre distribution and terminal equipment box, and nodes for customer indoor premises. Q16/15 further agreed new work items to revise L.201 and a new supplement on "Optical fibre cable Recommendations and standardization guideline".

Q17/15 worked on maintenance and operation of optical fibre cable networks and made good progress on new Recommendation L.tifm, which deals with telecommunication infrastructure facility management. Also, Q17/15 agreed to start a new work item for cable identification for construction and maintenance of optical fibre cable networks.

WP2 furthermore submitted a revised ITU-T Technical Report for agreement to the SG15 closing plenary meeting, "Guide on the use of ITU-T L-series Recommendations related to optical technologies for outside plant".

WP3/15 – Transport network characteristics

WP3 Chairman: Malcolm Betts; WP3 Vice-Chairman: Glenn Parsons

• In support of IMT‑2020/5G transport Q11/15 consented G.8300 “Characteristics of transport networks to support IMT-2020/5G" and G.709.4 “OTU 25 and OTU 50G short reach interfaces"
• Q13/15 agreed a technical report GSTR-GNSS “Considerations on the Use of GNSS as a Primary Time Reference in Telecommunications," consented several Recommendation and continued its work on network synchronization to support the requirements of IMT‑2020/5G.
• Q14/15 is continuing to working in cooperation with IEEE 802.1, IEEE 802.3, ONF, MEF, BBF, and IETF to provide consistent information models and YANG data models for Ethernet.
  
  

Q10/15 consented revised G.8032 (Ethernet ring protection switching) that introduces no technical changes. This and draft revised G.8012 (Ethernet UNI and NNI), G.8021 (Ethernet equipment) and G.8112 (MPLS-TP interfaces) have repatriated definitions from G.8001 and G.8101 and removed items formerly considered for further study. Q10/15 agreed a revised Implementers' Guide to G.8001 to reflect the removal of terms moved to G.8032. The work to simplify Ethernet recommendations via direct referencing of relevant mechanisms specified in non-ITU-T standards continued in draft revised G.8021 and was expanded to include draft revised G.8012. Agreements were reached for revised G.8012 to supersede G.8012.1, and for revised G.8021 and revised G.8012 to together supersede G.8021.1. Future work is planned towards September 2020 consent of revised G.8011 (Ethernet services) as well as revised G.8012, G.8021, and G.8112.

Q11/15 made significant progress on many topics.  In the area of transport for 5G, revised G.709 and new Recommendation G.709.4 were consented, adding support for 25G and 50G ODU rates. Also, in the area of transport for 5G, agreement was reached to use FlexE as the basis for the section layer frame for G.mtn and progress was made toward selecting a path layer OAM mechanism for G.mtn.  In the area of long reach interfaces for OTN, agreement was reached on a FEC for 450 km applications, and work was initiated on a revision of G.709.3.  A revision to G.Sup.58 was agreed, adding description of 25G and 50G MFIs.  A new work item was initiated regarding sub-1G clients in OTN networks via a new path layer that will carry the sub-1G clients and be multiplexed into the ODU path layer.  Progress was also made in the area of OTN security, with the goal of agreeing G.Sup.otnsec in September.  Additional work planned for completion in September includes amendments to G.8023 and G.798, the revision to G.709.3, new Recommendation G.mtn, and a new Supplement concerning aggregation of sub-1G services at the edge of an OTN network.  Q11/15 intends to hold two interim meetings to continue work on these and other topics,

Q12/15 completed work on G.807 (Generic functional architecture of the optical media network). G.807 was Approved, it is the first separate Recommendation to describe optical media. It complements G.800 (Unified functional architecture of transport networks) which provides architectural constructs that can describe digital transport networks. Optical media supports information transfer that is the subject of SG15 work on transport technologies such as OTN, PON, Visible Light Communication, and Ethernet. Amendments were initiated to G.872 and the newly Approved G.807 to continue the study of media issues, particularly those at the boundary of digital layers and media. These issues are relevant to Q14/15 and Q11/15, and will require continued interaction with Q6/15.

Progress continued on management and control Recommendations (G.7701, G.7702, and G.7703) in cooperation with Q14/15.

The Optical Transport Networks & Technologies Standardization Workplan was updated using incoming liaisons from other SDOs. Issue 27 was produced at this meeting and liaised to many SDOs.

Two interim meetings are planned to progress the work. One on 11-15 May 2020 jointly with Q14/15, hosted by Ericsson and Ciena in Ottawa, Canada; and another one on 17-19 June 2020, hosted by ITU-T in Geneva.

Q13/15 made good progress at this meeting. It consented the new Recommendation G.8273.4 that specifies the “Timing characteristics of partial timing support telecom boundary clocks and telecom time slave clocks for use with partial timing support networks".

G.781 (Synchronization layer functions for frequency synchronization based on the physical layer) was revised addressing new enhanced clocks and frequency sync over OTN.

G.8260 (Definitions and terminology for synchronization in packet networks), G.8271 (Time and phase synchronization aspects of telecommunication networks) and G.8271.1 (Network limits for time synchronization in packet networks with full timing support from the network) were also revised to address important updates in the area of time synchronization (e.g. as related to the use of new accurate time sync clocks and enhanced synchronous Ethernet). On this topic a liaison was exchanged with O-RAN.

G.8261 Amd1 (Timing and synchronization aspects in packet networks) and G.8262 Amd1 (Timing characteristics of synchronous equipment slave clock) were amended with aspects related to enhanced synchronous Ethernet.  Other amendments were consented at this meeting: G.8272 Amd1 (Timing characteristics of primary reference time clocks), G.8273 Amd1 (Framework of phase and time clocks), G.8273.2 Amd1 (Timing characteristics of telecom boundary clocks and telecom time slave clocks for use with full timing support from the network).

The PTP profiles G.8275.1 and G.8275.2 were also revised at this meeting including several improvements.

A new Technical Report GSTR-GNSS (Considerations on the Use of GNSS as a Primary Time Reference in Telecommunications), was agreed at this meeting. It provides information relevant to optimal GNSS reception in telecom applications where highly accurate time recovery is critical

Supplement G.Sup.SyncOAM also reached Agreement. It provides an overview of Synchronization operations, administration, maintenance (OAM), includes fault management, performance monitoring, alarms and events.

One interim meeting the week of 4 May 2020 in San Jose to progress work on network synchronization.

Q14/15 consented revised Recommendation G.875 on OTN management information model. Progress was made on the other seventeen active work items, including MC component/function management requirements (G.718) and information model (G.7719), common management requirements (G.7710), Core information model (G.7711), OTN management requirement for OTN (G.874), Media (G.876), Ethernet (G.8051 & G.8052 series), MPLS-TP (G.8152 series), synchronization (G.7721.1), MTN (G.mtn-mgmt). Q14/15 also initiated two new work items, one on revision to the architecture of control plane operations (G.7716) and revision to MPLS-TP management requirements (G.8151).

Q14/15 plans to hold two interim meetings to progress the work. One on 11-15 May 2020 jointly with Q12/15, hosted by Ericsson and Ciena in Ottawa, Canada; and another one on 15-19 June 2020, hosted by ITU-T in Geneva.

Q14/15 also plans to have monthly virtual meetings on information and data modelling coordination, specifically on Ethernet OAM and resilience, with IEEE 802.1, IEEE 802.3, ONF, MEF, IETF, and BBF experts being invited: Another series of virtual meetings will be held to continue preparation of G.876 for consent in September 2020.​

Decisions (ITU-T SG15, January/February 2019)
Approval 

WP1/15 – TAP Approval

WP1/15 – AAP Approval

WP3/15 – AAP Approval

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Consent

WP1/15 - Consent

WP2/15 - Consent

WP3/15 - Consent

* 30-day editing period was requested before initiating last call.

Agreement

WP1/15 - Agreement

WP2/15 - Agreement

WP3/15 - Agreement

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