BGP SR Policy Extensions for Segment List Identifier
draft-lin-idr-sr-policy-seglist-id-05

# Document Shepherd Write-Up for Group Documents

*This version is dated 4 July 2022.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this write-up to give helpful context to Last Call
and Internet Engineering Steering Group ([IESG][1]) reviewers, and your
diligence in completing it is appreciated. The full role of the shepherd is
further described in [RFC 4858][2]. You will need the cooperation of the authors
and editors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
  few individuals, with others being silent, or did it reach broad agreement?

Adoption: 10/20/2023 to 11/6/2023
Pro outside of authors: [11]  Hao Li, Fang Goa, Liyan Gong, Yuanxing Qui,Ran Chen,
Gyan Mishra, Nat Kao, MaChenhao, Xinxin Yi, Rubing Liu. Yixong Liu).
[operators: ~5] 

Hao Li:
https://mailarchive.ietf.org/arch/msg/idr/T0_B8NAFtQHdEhSktkJQvzffIAU/
Fang Goa (gaofang@mail.zgclab.edu.cn), 
https://mailarchive.ietf.org/arch/msg/idr/Nz0Rp5PdY8ZHB3mMmSv52npWP0o/
Liyan Gong
https://mailarchive.ietf.org/arch/msg/idr/ZQ96DiZgxa_ApuRb2VOt6dbedVc/
Qiuyuanxiang
https://mailarchive.ietf.org/arch/msg/idr/oA7sUNyj_tKg3TZ5z22gBi21OnU/
chen.ran@zte.com.cn
https://mailarchive.ietf.org/arch/msg/idr/Jy9huV_ZBCh5md8L-v76VhioaSk/
Gyan Mishra
https://mailarchive.ietf.org/arch/msg/idr/G5CUM_9CuUq39iQc77TXx_Wbr34/
Nat Kao
https://mailarchive.ietf.org/arch/msg/idr/uVeD42LJj_4A_8hYhOMRVq0Vpfg/
MaChenhao
https://mailarchive.ietf.org/arch/msg/idr/bzI-6e-YogbhXt0-Mcz3XHT9FRM/
Xinxin Yi
https://mailarchive.ietf.org/arch/msg/idr/GzxI8VsTugkvgZO1TDUK26ngruo/
Liurubing
https://mailarchive.ietf.org/arch/msg/idr/Sfm5YjDfW-UbwhwjUD-gNBVLFzk/
Yisong Liu
https://mailarchive.ietf.org/arch/msg/idr/vQ_7qt6PWCngStHkt0FxGAneMHQ/

Questions:
a) merge of draft-zhang-idr-sr-policy-metric-05 and draft-lin-idr-sr-policy-seglist-id,
  No merge: Hao Li (lihao@h3c.com) separate keeps modularity, Liyang Gaong, Ran Chen, Qiuyuanxiang, Ran Chen, Gyan Misra, Nat Kao.

Ran Chen: It is not neccessary to merge draft-zhang-idr-sr-policy-metric-05 and drft-lin-idr-sr-policy-seglist-id.
Gyan Mishra: Both drafts are different and have completely different purposes and should not  to be combined.
Nat Kao: No. Per-SID-List identifiers and per-SID-List metrics are independent attributes; it might be inappropriate to merge them
MaChenhao: No, these are two completely different drafts and it is recommended to keep them separate. The draft-zhang-idr-sr-policy-metric-05 primarily describes the metric for the seglist, whereas the draft-lin-idr-sr-policy-seglist-id explains the management identifier for the seglist.
Liurubing: not merged

merge: none.

b) Is there value in adding a segment list identifier?
yes Value: (Hao Li, Liyang Gaong, Fang Gao, Yuanxiang Qui, Ran Chen, Gyan Mishra, Nat Kao, MaChenhao. Yisong Liu

(Hao Li): segment list identifer uniquely identify a segment list and enable various applications such as configuration provisioning and statistical reporting. It enhances the flexibility and scalability of BGP SR deployments.
(Fang Gao):  To enable SBFD for each specific path in the SR Policy,  for the design of SBFD for SRv6 feature, we planned to augment the Yang Model and configure the SBFD parameter through Netconf (as for this kind of peripheral function of SRv6, the Yang standardizes and updates fast than the BGP extension). In this case, then, an identifier of each path will help a lot.  At the same time, if a network analyzer server is targeted to collect and display the lost packets counters and the delay measurements for each path, it is hard on implementation due to the lack of the identifier. And in the first step, we only got and show statistics of the whole SR Policy. An identifier of the path also will accelerate the development.
Qiuyuanxiang: After assigning an ID to the segment list, it will be more convenient for the controller to collect and process reported data or distribute configurations.
Nat Kao:  It provides a concise way of uniquely identifying an SID list.
MaChenhao: This identifier can be used to identify different seglists under a policy, differentiate various configurations, report statistics to the controller, and facilitate debugging and management.
Xinxin Yi:  This identifier can be used to identify different seglists under a policy, differentiate various configurations, report statistics to the controller, and facilitate debugging and management.


No value:

c) Any technical problems
none: (Hao Li)
Issue 1:
Gyan Mishra:
Today a SID list has a name that is referred to to by the SR policy candidate path that the BSID binds  to the forwarding plane for the path to be instantiated.  Could the Active candidate path [be] defined by the SID list using manual or autogenerated BSID to bind candidate path to a forwarding plane - Could the BSID be used [as] the identifier or even the name of the SID  list be used as
the SID ID in the SR policy TEA that is distributed to the controller?

Response (Changwang Lin)
Currently, BSID is at the candidate path level and is only used for traffic steering. However, BSID is not appropriate as the identifier for the SID list when there are multiple SID lists under a candidate path. Similarly, if a segment list references the candidate path name, it would face similar issues as mentioned above.

Gyan response: Understood that BSID cannot be used as there could be multiple SID lists under the candidate path.
I was not thinking [of] the candidate path name but the segment list name that could be used as the ID.  Also using Rest or Netconf / Yang you should be able to pull all the details of the SR policy and active candidate path and corresponding sid list details and the statistics or via API on the SIDs from the SR source node.  Everything that’s on the router cli and more should be able capture via methods mentioned.  As well from the stateful PCE/SDN controller router has the SR policy database as well you should be able to via API gather all the detailed sid statistics for monitoring from any vendor implementation specific front end GUI.

Changwan Lin:
Agree with you that segment list name is also an option. Before version-04 of this draft, both segment list ID sub-tlv and segment list name sub-tlv were defined. However, after discussions, SR policies would now have policy names, and candidate paths would have path names, so in each path, segment lists only need an ID for identification. Therefore, in the latest version, only segment list ID has been retained. Besides, PCEP [I-D.ietf-pce-multipath] also uses a 4-octet ID (called Path ID) to identify segment list.


2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?

3. Has anyone threatened an appeal or otherwise indicated extreme discontent? If
  so, please summarize the areas of conflict in separate email messages to the
  responsible Area Director. (It should be in a separate email because this
  questionnaire is publicly available.)

4. For protocol documents, are there existing implementations of the contents of
  the document? Have a significant number of potential implementers indicated
  plans to implement? Are any existing implementations reported somewhere,
  either in the document itself (as [RFC 7942][3] recommends) or elsewhere
  (where)?

## Additional Reviews

5. Do the contents of this document closely interact with technologies in other
  IETF working groups or external organizations, and would it therefore benefit
  from their review? Have those reviews occurred? If yes, describe which
  reviews took place.

6. Describe how the document meets any required formal expert review criteria,
  such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

7. If the document contains a YANG module, has the final version of the module
  been checked with any of the [recommended validation tools][4] for syntax and
  formatting validation? If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time? Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?

8. Describe reviews and automated checks performed to validate sections of the
  final version of the document written in a formal language, such as XML code,
  BNF rules, MIB definitions, CBOR's CDDL, etc.

## Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
  document is needed, clearly written, complete, correctly designed, and ready
  to be handed off to the responsible Area Director?

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. For which areas have such issues been identified
    and addressed? For which does this still need to happen in subsequent
    reviews?

11. What type of RFC publication is being requested on the IETF stream ([Best
    Current Practice][12], [Proposed Standard, Internet Standard][13],
    [Informational, Experimental or Historic][14])? Why is this the proper type
    of RFC? Do all Datatracker state attributes correctly reflect this intent?

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]? To
    the best of your knowledge, have all required disclosures been filed? If
    not, explain why. If yes, summarize any relevant discussion, including links
    to publicly-available messages when applicable.

Mengxiao.Chen
https://mailarchive.ietf.org/arch/msg/idr/GdU2CbQYBotUTZ5YhHhy0XGCWoU/

Yao Liu (liu.yao71@zte.com.cn)
https://mailarchive.ietf.org/arch/msg/idr/LSE3e8DzHRFd5LXGFeYYfoXYSr0/

Ketan Talaulikar
https://mailarchive.ietf.org/arch/msg/idr/gCWJlTLI6tzGlIzQYzwMTXlP8gQ/

linchangwang
https://mailarchive.ietf.org/arch/msg/idr/0UwsHeD804DC6PBMhjuJ9rTRdqU/

Weiqiang Cheng
https://mailarchive.ietf.org/arch/msg/idr/EPX3JJ-jvb9peNXc6WKEUOhl6u8/

13. Has each author, editor, and contributor shown their willingness to be
    listed as such? If the total number of authors and editors on the front page
    is greater than five, please provide a justification.


14. Document any remaining I-D nits in this document. Simply running the [idnits
    tool][8] is not enough; please review the ["Content Guidelines" on
    authors.ietf.org][15]. (Also note that the current idnits tool generates
    some incorrect warnings; a rewrite is underway.)

15. Should any informative references be normative or vice-versa? See the [IESG
    Statement on Normative and Informative References][16].

16. List any normative references that are not freely available to anyone. Did
    the community have sufficient access to review any such normative
    references?

17. Are there any normative downward references (see [RFC 3967][9] and [BCP
    97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
    list them.

18. Are there normative references to documents that are not ready to be
    submitted to the IESG for publication or are otherwise in an unclear state?
    If so, what is the plan for their completion?

19. Will publication of this document change the status of any existing RFCs? If
    so, does the Datatracker metadata correctly reflect this and are those RFCs
    listed on the title page, in the abstract, and discussed in the
    introduction? If not, explain why and point to the part of the document
    where the relationship of this document to these other RFCs is discussed.

20. Describe the document shepherd's review of the IANA considerations section,
    especially with regard to its consistency with the body of the document.
    Confirm that all aspects of the document requiring IANA assignments are
    associated with the appropriate reservations in IANA registries. Confirm
    that any referenced IANA registries have been clearly identified. Confirm
    that each newly created IANA registry specifies its initial contents,
    allocations procedures, and a reasonable name (see [RFC 8126][11]).

21. List any new IANA registries that require Designated Expert Review for
    future allocations. Are the instructions to the Designated Expert clear?
    Please include suggestions of designated experts, if appropriate.

[1]: https://www.ietf.org/about/groups/iesg/
[2]: https://www.rfc-editor.org/rfc/rfc4858.html
[3]: https://www.rfc-editor.org/rfc/rfc7942.html
[4]: https://wiki.ietf.org/group/ops/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://wiki.ietf.org/group/iesg/ExpertTopics
[7]: https://www.rfc-editor.org/info/bcp79
[8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html
[10]: https://www.rfc-editor.org/info/bcp97
[11]: https://www.rfc-editor.org/rfc/rfc8126.html
[12]: https://www.rfc-editor.org/rfc/rfc2026.html#section-5
[13]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1
[14]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2
[15]: https://authors.ietf.org/en/content-guidelines-overview
[16]: https://www.ietf.org/about/groups/iesg/statements/normative-informative-references/
[17]: https://datatracker.ietf.org/doc/downref/

# Document Shepherd Write-Up for Group Documents

*This version is dated 4 July 2022.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this write-up to give helpful context to Last Call
and Internet Engineering Steering Group ([IESG][1]) reviewers, and your
diligence in completing it is appreciated. The full role of the shepherd is
further described in [RFC 4858][2]. You will need the cooperation of the authors
and editors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
  few individuals, with others being silent, or did it reach broad agreement?

Adoption: 10/20/2023 to 11/6/2023
Pro outside of authors: Hao Li, Fang Goa, Liyan Gong
Hao Li:
https://mailarchive.ietf.org/arch/msg/idr/T0_B8NAFtQHdEhSktkJQvzffIAU/
Fang Goa (gaofang@mail.zgclab.edu.cn), 
https://mailarchive.ietf.org/arch/msg/idr/Nz0Rp5PdY8ZHB3mMmSv52npWP0o/
Liyan Gong
https://mailarchive.ietf.org/arch/msg/idr/ZQ96DiZgxa_ApuRb2VOt6dbedVc/

Questions:
a) merge of draft-zhang-idr-sr-policy-metric-05 and draft-lin-idr-sr-policy-seglist-id,
  No merge: Hao Li (lihao@h3c.com) separate keeps modularity, Liyang Gaong,
  merge:

b) Is there value in adding a segment list identifier?
Value: (Hao Li, Liyang Gaong)

(Hao Li): segment list identifer uniquely identify a segment list and enable various applications such as configuration provisioning and statistical reporting. It enhances the flexibility and scalability of BGP SR deployments.
(Fang Gao):  To enable SBFD for each specific path in the SR Policy,  for the design of SBFD for SRv6 feature, we planned to augment the Yang Model and configure the SBFD parameter through Netconf (as for this kind of peripheral function of SRv6, the Yang standardizes and updates fast than the BGP extension). In this case, then, an identifier of each path will help a lot.  At the same time, if a network analyzer server is targeted to collect and display the lost packets counters and the delay measurements for each path, it is hard on implementation due to the lack of the identifier. And in the first step, we only got and show statistics of the whole SR Policy. An identifier of the path also will accelerate the development.
yes:

No value:

c) Any technical problems
none: (Hao Li)

2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?

3. Has anyone threatened an appeal or otherwise indicated extreme discontent? If
  so, please summarize the areas of conflict in separate email messages to the
  responsible Area Director. (It should be in a separate email because this
  questionnaire is publicly available.)

4. For protocol documents, are there existing implementations of the contents of
  the document? Have a significant number of potential implementers indicated
  plans to implement? Are any existing implementations reported somewhere,
  either in the document itself (as [RFC 7942][3] recommends) or elsewhere
  (where)?

## Additional Reviews

5. Do the contents of this document closely interact with technologies in other
  IETF working groups or external organizations, and would it therefore benefit
  from their review? Have those reviews occurred? If yes, describe which
  reviews took place.

6. Describe how the document meets any required formal expert review criteria,
  such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

7. If the document contains a YANG module, has the final version of the module
  been checked with any of the [recommended validation tools][4] for syntax and
  formatting validation? If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time? Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?

8. Describe reviews and automated checks performed to validate sections of the
  final version of the document written in a formal language, such as XML code,
  BNF rules, MIB definitions, CBOR's CDDL, etc.

## Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
  document is needed, clearly written, complete, correctly designed, and ready
  to be handed off to the responsible Area Director?

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. For which areas have such issues been identified
    and addressed? For which does this still need to happen in subsequent
    reviews?

11. What type of RFC publication is being requested on the IETF stream ([Best
    Current Practice][12], [Proposed Standard, Internet Standard][13],
    [Informational, Experimental or Historic][14])? Why is this the proper type
    of RFC? Do all Datatracker state attributes correctly reflect this intent?

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]? To
    the best of your knowledge, have all required disclosures been filed? If
    not, explain why. If yes, summarize any relevant discussion, including links
    to publicly-available messages when applicable.

Mengxiao.Chen
https://mailarchive.ietf.org/arch/msg/idr/GdU2CbQYBotUTZ5YhHhy0XGCWoU/



13. Has each author, editor, and contributor shown their willingness to be
    listed as such? If the total number of authors and editors on the front page
    is greater than five, please provide a justification.


14. Document any remaining I-D nits in this document. Simply running the [idnits
    tool][8] is not enough; please review the ["Content Guidelines" on
    authors.ietf.org][15]. (Also note that the current idnits tool generates
    some incorrect warnings; a rewrite is underway.)

15. Should any informative references be normative or vice-versa? See the [IESG
    Statement on Normative and Informative References][16].

16. List any normative references that are not freely available to anyone. Did
    the community have sufficient access to review any such normative
    references?

17. Are there any normative downward references (see [RFC 3967][9] and [BCP
    97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
    list them.

18. Are there normative references to documents that are not ready to be
    submitted to the IESG for publication or are otherwise in an unclear state?
    If so, what is the plan for their completion?

19. Will publication of this document change the status of any existing RFCs? If
    so, does the Datatracker metadata correctly reflect this and are those RFCs
    listed on the title page, in the abstract, and discussed in the
    introduction? If not, explain why and point to the part of the document
    where the relationship of this document to these other RFCs is discussed.

20. Describe the document shepherd's review of the IANA considerations section,
    especially with regard to its consistency with the body of the document.
    Confirm that all aspects of the document requiring IANA assignments are
    associated with the appropriate reservations in IANA registries. Confirm
    that any referenced IANA registries have been clearly identified. Confirm
    that each newly created IANA registry specifies its initial contents,
    allocations procedures, and a reasonable name (see [RFC 8126][11]).

21. List any new IANA registries that require Designated Expert Review for
    future allocations. Are the instructions to the Designated Expert clear?
    Please include suggestions of designated experts, if appropriate.

[1]: https://www.ietf.org/about/groups/iesg/
[2]: https://www.rfc-editor.org/rfc/rfc4858.html
[3]: https://www.rfc-editor.org/rfc/rfc7942.html
[4]: https://wiki.ietf.org/group/ops/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://wiki.ietf.org/group/iesg/ExpertTopics
[7]: https://www.rfc-editor.org/info/bcp79
[8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html
[10]: https://www.rfc-editor.org/info/bcp97
[11]: https://www.rfc-editor.org/rfc/rfc8126.html
[12]: https://www.rfc-editor.org/rfc/rfc2026.html#section-5
[13]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1
[14]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2
[15]: https://authors.ietf.org/en/content-guidelines-overview
[16]: https://www.ietf.org/about/groups/iesg/statements/normative-informative-references/
[17]: https://datatracker.ietf.org/doc/downref/