Bidirectional Forwarding Detection (BFD) Directed Return Path for MPLS Label Switched Paths (LSPs)
draft-ietf-mpls-bfd-directed-30

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

IANA has completed its review of draft-ietf-mpls-bfd-directed-27. If any part of this review is inaccurate, please let us know.

IANA has a question about the first action requested in the IANA Considerations section of this document.

IANA understands that, upon approval of this document, there are two actions which we must complete.

First, in the TLV registry in the Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters registry group located at:

https://www.iana.org/assignments/mpls-lsp-ping-parameters/

a single new TLV is to be registered from the 16384-31739 range as follows:

Value: [ TBD-at-Registration ]
TLV Name: BFD Reverse Path TLV
Reference: [ RFC-to-be ]
Sub-TLV Registry:

IANA Question --> will there be a sub-TLV registry for this new TLV?

Second, in the Return Codes registry, also in the Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters registry group located at:

https://www.iana.org/assignments/mpls-lsp-ping-parameters/

two new return codes are to be registered from the 192-247 range as follows:

Value: [ TBD-at-Registration ]
Meaning: Inappropriate Target FEC Stack sub-TLV present.
Reference: [ RFC-to-be ]

Value: [ TBD-at-Registration ]
Meaning: Failed to establish the BFD session. The specified reverse path was not found.
Reference: [ RFC-to-be ]

We understand that these are the only actions required to be completed upon approval of this document.

NOTE: The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is meant only to confirm the list of actions that will be performed.

For definitions of IANA review states, please see:

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

Thank you,

David Dong
IANA Services Sr. Specialist

The following Last Call announcement was sent out (ends 2024-04-15):

From: The IESG
To: IETF-Announce
CC: Nicolai Leymann , draft-ietf-mpls-bfd-directed@ietf.org, james.n.guichard@futurewei.com, mpls-chairs@ietf.org, mpls@ietf.org, n.leymann@telekom.de
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Bidirectional Forwarding Detection (BFD) Directed Return Path for MPLS Label Switched Paths (LSPs)) to Experimental RFC


The IESG has received a request from the Multiprotocol Label Switching WG
(mpls) to consider the following document: - 'Bidirectional Forwarding
Detection (BFD) Directed Return Path for MPLS
  Label Switched Paths (LSPs)'
  as Experimental RFC

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 2024-04-15. 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


  Bidirectional Forwarding Detection (BFD) is expected to be able to
  monitor a wide variety of encapsulations of paths between systems.
  When a BFD session monitors an explicitly routed unidirectional path
  there may be a need to direct egress BFD peer to use a specific path
  for the reverse direction of the BFD session.  This document
  describes an extension to the MPLS Label Switched Path (LSP) echo
  request that allows a BFD system requests that the remote BFD peer
  transmits BFD control packets over the specified LSP.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-mpls-bfd-directed/


The following IPR Declarations may be related to this I-D:

  https://datatracker.ietf.org/ipr/2625/
  https://datatracker.ietf.org/ipr/2769/
  https://datatracker.ietf.org/ipr/2892/

## 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?
During Last Call the draft received support from five people who are not document authors. There were no voices or concerns raised moving the document forward towards publication. This is of particular importance because there was a controversy about earlier versions of the draft which were solved during several iterations of the document (for details see next sections below).

2 - Was there controversy about particular points, or were there decisions where the consensus was particularly rough?
The draft has a long history and went through several major updates. In total there where four WGLC necessary in order to address all issues raised on the document. The first three working group calls failed due to technical concerns mainly related to  the question if the feature addressed in the draft is fragile and wether this means that the problem described is being solved by the document.

For more details see:
https://mailarchive.ietf.org/arch/msg/mpls/iXsENQuPWmmgsueNiUMlyRCcu4U/
https://mailarchive.ietf.org/arch/msg/mpls/pYhEHsGAg13KBJ6PkPWeL3CnQp4/

In summary the conclusion is that the feature is in several environments fragile and does not guarantee to solve the problem (because in case BFD chooses it's own return path that this session might be less stable than the tunnel being tested). But on the other hand in static environments it solves the problem and there are cases where people might want to implement and run the solution described in the document (as an option to use to solve a specific problem). This is overall a fair assumption. The draft was updated to reflect this and also moved from "Proposed Standard" to "Experimental" marking the approach being part of a research or development effort.

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 (see above).

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)?
Yes. There is one implementation  reported by ZTE.

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.
None needed.

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.
N/A.

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]?
N/A.

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.
N/A.

### 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?
Yes.

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?
None.

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?
Experimental.  This state attribute is also reflected in the Datatracker.

12 - Have reasonable efforts been made to remind all authors of the intellectual property rights (IPR) disclosure obligations described in [BCP 79][8]? 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.
Yes.
There are three IPRs listed for the document:
https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-mpls-bfd-directed
One of the reasons for the controversial discussion was related to IPR2625 because it did not contain any IPR text:
https://datatracker.ietf.org/ipr/2625/

Authors of the draft are claiming, that the IPR2625 is not applicable anymore. IPR2625 is still listed in the Datatracker and was updated by IPR2769). For more details see:
https://mailarchive.ietf.org/arch/msg/mpls/imnwjd0the9F-F4gdHxh_J3xzq4/
https://datatracker.ietf.org/ipr/2769/


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 pageis greater than five, please provide a justification.
Yes (number of authors on the front page is four).

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.)
No issues found by I-D nits and review:
Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--).

15 - Should any informative references be normative or vice-versa? See the [IESG Statement on Normative and Informative References][16].
No.

16 - List any normative references that are not freely available to anyone. Did the community have sufficient access to review any such normative references?
None.

17 - Are there any normative downward references (see [RFC3967][9] and [BCP97][10]) that are not already listed in the [DOWNREF registry][17]? If so, list them.
No.

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?
No. Only RFCs are referenced.

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.

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]).
The IANA is requested to assign a new value for BFD Reverse Path TLV from the 16384-31739 range in the "TLVs" registry of "Multiprotocol Label Switching Architecture (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry. In addition assignment of a  new Return Code values from the 192-247 range of the "Multi-Protocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry, "Return Codes" subregistry is necessary.  The ranges 16384-31739 and 192-247 use the “RFC Required” assignment policy and so are appropriate for an Experimental RFC.

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.
None.


[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 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?
During Last Call the draft received support from five people who are not document authors. There were no voices or concerns raised moving the document forward towards publication. This is of particular importance because there was a controversy about earlier versions of the draft which were solved during several iterations of the document (for details see next sections below).

2 - Was there controversy about particular points, or were there decisions where the consensus was particularly rough?
The draft has a long history and went through several major updates. In total there where four WGLC necessary in order to address all issues raised on the document. The first three working group calls failed due to technical concerns mainly related to  the question if the feature addressed in the draft is fragile and wether this means that the problem described is being solved by the document.

For more details see:
https://mailarchive.ietf.org/arch/msg/mpls/iXsENQuPWmmgsueNiUMlyRCcu4U/
https://mailarchive.ietf.org/arch/msg/mpls/pYhEHsGAg13KBJ6PkPWeL3CnQp4/

In summary the conclusion is that the feature is in several environments fragile and does not guarantee to solve the problem (because in case BFD chooses it's own return path that this session might be less stable than the tunnel being tested). But on the other hand in static environments it solves the problem and there are cases where people might want to implement and run the solution described in the document (as an option to use to solve a specific problem). This is overall a fair assumption. The draft was updated to reflect this and also moved from "Proposed Standard" to "Experimental" marking the approach being part of a research or development effort.

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 (see above).

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)?
Yes. There is one implementation  reported by ZTE.

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.
None needed.

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.
N/A.

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]?
N/A.

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.
N/A.

### 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?
Yes.

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?
None.

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?
Experimental.  This state attribute is also reflected in the Datatracker.

12 - Have reasonable efforts been made to remind all authors of the intellectual property rights (IPR) disclosure obligations described in [BCP 79][8]? 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.
Yes.
There are three IPRs listed for the document:
https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-mpls-bfd-directed
One of the reasons for the controversial discussion was related to IPR2625 because it did not contain any IPR text:
https://datatracker.ietf.org/ipr/2625/

Authors of the draft are claiming, that the IPR2625 is not applicable anymore. IPR2625 is still listed in the Datatracker and was updated by IPR2769). For more details see:
https://mailarchive.ietf.org/arch/msg/mpls/imnwjd0the9F-F4gdHxh_J3xzq4/
https://datatracker.ietf.org/ipr/2769/


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 pageis greater than five, please provide a justification.
Yes (number of authors on the front page is four).

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.)
No issues found by I-D nits and review:
Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--).

15 - Should any informative references be normative or vice-versa? See the [IESG Statement on Normative and Informative References][16].
No.

16 - List any normative references that are not freely available to anyone. Did the community have sufficient access to review any such normative references?
None.

17 - Are there any normative downward references (see [RFC3967][9] and [BCP97][10]) that are not already listed in the [DOWNREF registry][17]? If so, list them.
No.

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?
No. Only RFCs are referenced.

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.

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]).
The IANA is requested to assign a new value for BFD Reverse Path TLV from the 16384-31739 range in the "TLVs" registry of "Multiprotocol Label Switching Architecture (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry. In addition assignment of a  new Return Code values from the 192-247 range of the "Multi-Protocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry, "Return Codes" subregistry is necessary.  The ranges 16384-31739 and 192-247 use the “RFC Required” assignment policy and so are appropriate for an Experimental RFC.

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.
None.


[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 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?
During Last Call the draft received support from five people who are not document authors. There were no voices or concerns raised moving the document forward towards publication. This is of particular importance because there was a controversy about earlier versions of the draft which were solved during several iterations of the document (for details see next sections below).

2 - Was there controversy about particular points, or were there decisions where the consensus was particularly rough?
The draft has a long history and went through several major updates. In total there where four WGLC necessary in order to address all issues raised on the document. The first three working group calls failed due to technical concerns mainly related to  the question if the feature addressed in the draft is fragile and wether this means that the problem described is being solved by the document.

For more details see:
https://mailarchive.ietf.org/arch/msg/mpls/iXsENQuPWmmgsueNiUMlyRCcu4U/
https://mailarchive.ietf.org/arch/msg/mpls/pYhEHsGAg13KBJ6PkPWeL3CnQp4/

In summary the conclusion is that the feature is in several environments fragile and does not guarantee to solve the problem (because in case BFD chooses it's own return path that this session might be less table thant the tunnel being tested). But on the other hand in static environments it solves the problem and there are cases where people might want to implement and run the solution descrtibed in the document (as an option to use to solve a specific problem). This is overall a fair assumption. The draft was updated to reflect this and also moved from "Proposed Standard" to "Experimental" marking the approach being part of a research or development effort.

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 (see above).

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)?
Yes. There is one implementation  reported by ZTE.

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.
None needed.

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.
N/A.

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]?
N/A.

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.
N/A.

### 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?
Yes.

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?
None.

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?
Experimental.  This state attribute is also reflected in the Datatracker.

12 - Have reasonable efforts been made to remind all authors of the intellectual property rights (IPR) disclosure obligations described in [BCP 79][8]? 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.
Yes.
There are three IPRs listed for the document:
https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-mpls-bfd-directed
One of the reasons for the controversial discussion was related to IPR2625 because it did not contain any IPR text:
https://datatracker.ietf.org/ipr/2625/

Authors of the draft are claiming, that the IPR2625 is not applicable anymore. IPR2625 is still listed in the Datatracker and was updated by IPR2769). For more details see:
https://mailarchive.ietf.org/arch/msg/mpls/imnwjd0the9F-F4gdHxh_J3xzq4/
https://datatracker.ietf.org/ipr/2769/


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 pageis greater than five, please provide a justification.
Yes (number of authors on the front page is four).

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.)
No issues found by I-D nits and review:
Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--).

15 - Should any informative references be normative or vice-versa? See the [IESG Statement on Normative and Informative References][16].
No.

16 - List any normative references that are not freely available to anyone. Did the community have sufficient access to review any such normative references?
None.

17 - Are there any normative downward references (see [RFC3967][9] and [BCP97][10]) that are not already listed in the [DOWNREF registry][17]? If so, list them.
No.

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?
No. Only RFCs are referenced.

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.

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]).
The IANA is requested to assign a new value for BFD Reverse Path TLV from the 16384-31739 range in the "TLVs" registry of "Multiprotocol Label Switching Architecture (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry. In addition assignment of a  new Return Code values from the 192-247 range of the "Multi-Protocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry, "Return Codes" subregistry is necessary.  The ranges 16384-31739 and 192-247 use the “RFC Required” assignment policy and so are appropriate for an Experimental RFC.

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.
None.


[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/

Notification list changed to "Martin Vigoureux" <martin.vigoureux@nokia.com>, "Nicolai Leymann" <n.leymann@telekom.de> from "Martin Vigoureux" <martin.vigoureux@nokia.com>, loa@pi.nu, "Nicolai Leymann" <n.leymann@telekom.de>

WG Last call was already done:

https://mailarchive.ietf.org/arch/msg/mpls/v4ZxTPCGmvhsNA8VtMVvG8lGIik/

The document was stuck in the datatacker, need to move to WG Last Call in order to be able to request publication.