PBB-EVPN ISID-based C-MAC-Flush
draft-ietf-bess-pbb-evpn-isid-cmacflush-09

Received changes through RFC Editor sync (changed state to RFC, created became rfc relationship between draft-ietf-bess-pbb-evpn-isid-cmacflush and RFC 9541, changed IESG state to RFC Published)

[Ballot comment]
The term "B-Component" is in the glossary, but isn't used in this document.  Same with "CE" and "vES".

I find the use of SHOULD around an administrative option to be peculiar.  This is normally associated with interoperability requirements, but even setting that aside, let's say I decide to implement this in a way that the solution overall or the capability defined in Section 4 simply can't be enabled or disabled.  Is the implementation still viable?  I also concur with John's point that the SHOULD-MAY combination is similarly strange.

[Ballot comment]
The term "B-Component" is in the glossary, but isn't used in this document.  Same with "CE" and "vES".

I find the use of SHOULD around an administrative option to be peculiar.  This is normally associated with interoperability requirements, but even setting that aside, let's say I decide to implement this in a way that the solution overall or the capability defined in Section 4 simply can't be enabled or disabled.  Is the implementation still viable?

[Ballot comment]
I fully agree with Eric's "This is a very specific area of work and the text is not easy to read for a non expert. I read it, but was somewhat baffled by the quantity of acronyms and terminology, and to I too relied on Pascal Thubert's IntDir review (https://datatracker.ietf.org/doc/review-ietf-bess-pbb-evpn-isid-cmacflush-08-intdir-telechat-thubert-2023-08-07/) to help choose my position.

[Ballot comment]

# Éric Vyncke, INT AD, comments for draft-ietf-bess-pbb-evpn-isid-cmacflush-08

Thank you for the work put into this document. This is a very specific area of work and the text is not easy to read for a non expert. So, I was happy to rely on the Internet directorate review below by Pascal.

Please find below some non-blocking COMMENT points (but replies would be appreciated even if only for my own education).

Special thanks to Matthew Bocci for the shepherd's detailed write-up including the WG consensus and the justification of the intended status.

Other thanks to Pascal Thubert, the Internet directorate reviewer (at my request), please consider this int-dir review as if it was mine:
https://datatracker.ietf.org/doc/draft-ietf-bess-pbb-evpn-isid-cmacflush/reviewrequest/17846/

I hope that this review helps to improve the document,

Regards,

-éric

# COMMENTS

## Abstract

No need for action, but I have rarely seen such an acronym-dense abstract, it is therefore hard to read.

## G.8032

G.8032 should be an informative reference (this would be DISCUSS level issue if the reference was normative).

## Scalability

Should there be some text about the scalability issues ? I.e., MAC addresses move (Wi-Fi roaming) and are changing (cfr MADINAS WG).

[Ballot comment]
- General: I'm taking it on faith that the flush procedures are properly specified in one of the underlying specs. This one doesn't, it just is an overlay that says "do the flush procedure but with this different trigger".

- General: G.8032 should be at least an Informative reference.

- Section 1.1: Terms defined but never used, or used only once (so could be inline)
  - B-Component (used only once)
  - vES (never used)
  - I-Component (only used once)
  - RD and RT are used only once, too

- Section 2(d), It's not obvious to me what "double flushing" means (and I do know something about route reflectors).

- Section 3, "The MAC Mobility extended community is used as in [RFC7623], where a delta in the sequence number between two updates for the same B-MAC/I-SID will be interpreted as a C-MAC-flush notification for the corresponding B-MAC and I-SID", it seems to me that "a delta in the sequence number" is a more casual description than is warranted? Looking at RFC 7423, it appears the sequence number has to be incremented (modulo sequence wrap), not just different (which is what "delta" implies). I guess a simple fix would be s/a delta/an increment/. (Occurs again in Section 4.2, and again in Section 4.3. Just grep for "delta".)

- Section 4, where you write "Enabling or disabling I-SID-based C-MAC-flush SHOULD be an administrative choice on the system that MAY be configured per I-SID (I-Component). When enabled on a PE:", do you really mean the MAY to be interpreted in the sense of RFC 2119, i.e. it's completely optional? Or do you mean "may"?

- Section 5(e), "The solution can coexist in a network with systems supporting or not supporting this specification." I guess the coexistence with non-supporting systems is that they just ignore the new style of route, and have to age out the MACs the old-fashioned way (with concomitant loss of traffic)?

[Ballot comment]
# GEN AD review of draft-ietf-bess-pbb-evpn-isid-cmacflush-08

CC @larseggert

Thanks to Joel Halpern for the General Area Review Team (Gen-ART) review
(https://mailarchive.ietf.org/arch/msg/gen-art/CBzsxEwRDvcvkn70BvytwrKRLEg).

## Notes

This review is in the ["IETF Comments" Markdown format][ICMF], You can use the
[`ietf-comments` tool][ICT] to automatically convert this review into
individual GitHub issues. Review generated by the [`ietf-reviewtool`][IRT].

[ICMF]: https://github.com/mnot/ietf-comments/blob/main/format.md
[ICT]: https://github.com/mnot/ietf-comments
[IRT]: https://github.com/larseggert/ietf-reviewtool

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Functions Operator has reviewed draft-ietf-bess-pbb-evpn-isid-cmacflush-08, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any registry actions.

While it's often helpful for a document's IANA Considerations section to remain in place upon publication even if there are no actions, if the authors strongly prefer to remove it, we do not object.

If this assessment is not accurate, please respond as soon as possible.

For definitions of IANA review states, please see:

https://datatracker.ietf.org/help/state/draft/iana-review

Thank you,

David Dong
IANA Services Specialist

The following Last Call announcement was sent out (ends 2023-07-11):

From: The IESG
To: IETF-Announce
CC: andrew-ietf@liquid.tech, bess-chairs@ietf.org, bess@ietf.org, draft-ietf-bess-pbb-evpn-isid-cmacflush@ietf.org, matthew.bocci@nokia.com
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (PBB-EVPN ISID-based CMAC-Flush) to Proposed Standard


The IESG has received a request from the BGP Enabled ServiceS WG (bess) to
consider the following document: - 'PBB-EVPN ISID-based CMAC-Flush'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
last-call@ietf.org mailing lists by 2023-07-11. Exceptionally, comments may
be sent to iesg@ietf.org instead. In either case, please retain the beginning
of the Subject line to allow automated sorting.

Abstract


  Provider Backbone Bridging (PBB) can be combined with Ethernet
  Virtual Private Networks (EVPN) to deploy Ethernet Local Area Network
  (ELAN) services in large Multi-Protocol Label Switching (MPLS)
  networks (PBB-EVPN).  Single-Active Multi-homing and per-I-SID (per
  Service Instance Identifier) Load-Balancing can be provided to access
  devices and aggregation networks.  In order to speed up the network
  convergence in case of failures on Single-Active Multi-Homed Ethernet
  Segments, PBB-EVPN defines a flush mechanism for Customer MACs (CMAC-
  flush) that works for different Ethernet Segment Backbone MAC (BMAC)
  address allocation models.  This document complements those CMAC-
  flush procedures for cases in which no PBB-EVPN Ethernet Segments are
  defined (the attachment circuit is associated to a zero Ethernet
  Segment Identifier) and a Service Instance Identifier based (I-SID-
  based) CMAC-flush granularity is required.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-bess-pbb-evpn-isid-cmacflush/



No IPR declarations have been submitted directly on this I-D.

# 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?

This is a document that has been developed within the working group over a number of years. I believe it has broad consensus.


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

None indicated.

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.)

None indicated.

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)?

At least one implementation in shipping code has been declared as a part of the BESS implementation poll for the draft.


## 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.

The draft was reviewed by the Routing Area directorate and comments addressed.
The draft relates to extensions to RFC7623 (PBB combined with EVPN) which I believe lies within the domain of BESS and does not require further external reviews.

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.

Not app;licable.

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]?

Not applicable

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.

The document does not contain formal language that need further review.

## 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?

I have reviewed v05 of the draft in detail and provided a review to the authors. I believe it is clearly written and ready to be handed to the AD.

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?

No issues identified.


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?

Standards Track i.e. proposed standard. This is appropriate as the draft specifies protocol extensions and behaviors that must be followed for interoperability..

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.

An IPR poll was carried out on the BESS list at the time of the WG last call.

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.

Yes. There are 5 co-authors.


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.)

The document appears to comply to ID Nits and relevant content guidelines.


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

The references appear to be correctly classified.

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

All normative references are to published RFCs.

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.

None

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?

None

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.

No impact on existing RFCs.

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]).

There are no IANA actions.

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://trac.ietf.org/trac/ops/wiki/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://trac.ietf.org/trac/iesg/wiki/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?

This is a document that has been developed within the working group over a number of years. I believe it has broad consensus.


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

None indicated.

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.)

None indicated.

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)?

At least one implementation in shipping code has been declared as a part of the BESS implementation poll for the draft.


## 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.

The draft was reviewed by the Routing Area directorate and comments addressed.
The draft relates to extensions to RFC7623 (PBB combined with EVPN) which I believe lies within the domain of BESS and does not require further external reviews.

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.

Not app;licable.

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]?

Not applicable

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.

The document does not contain formal language that need further review.

## 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?

I have reviewed v05 of the draft in detail and provided a review to the authors. I believe it is clearly written and ready to be handed to the AD.

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?

No issues identified.


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?

Standards Track i.e. proposed standard. This is appropriate as the draft specifies protocol extensions and behaviors that must be followed for interoperability..

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.

An IPR poll was carried out on the BESS list at the time of the WG last call.

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.

Yes. There are 5 co-authors.


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.)

The document appears to comply to ID Nits and relevant content guidelines.


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

The references appear to be correctly classified.

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

All normative references are to published RFCs.

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.

None

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?

None

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.

No impact on existing RFCs.

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]).

There are no IANA actions.

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://trac.ietf.org/trac/ops/wiki/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://trac.ietf.org/trac/iesg/wiki/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/