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Shepherd writeup

## 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:

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:
One of the reasons for the controversial discussion was related to IPR2625
because it did not contain any IPR text:

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:

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][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?

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.