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Shepherd writeup

: Document Writeup for Working Group Documents
: As required by RFC 4858, this is the current template for the Document
: Shepherd Write-Up.
: Changes are expected over time. This version is dated 24 February 2012.
: (1) What type of RFC is being requested (BCP, Proposed Standard,
: Internet Standard, Informational, Experimental, or Historic)? Why is
: this the proper type of RFC? Is this type of RFC indicated in the title
: page header?

This draft is being targeted for Informational status.  While the draft
recommends a number of timer values, they are suggested for
interoperability while not mandating that any particular value be

There was discussion on the mailing list that while the draft was listed
as Informational that some customers were likely to take the RFC as a
base set of standard values - thus a de facto standard.  Consensus of
the list seemed to judge that this was okay and provided values that
implementors may want to look at targeting as part of their

: (2) The IESG approval announcement includes a Document Announcement
: Write-Up. Please provide such a Document Announcement Write-Up. Recent
: examples can be found in the "Action" announcements for approved
: documents. The approval announcement contains the following sections:
: Technical Summary:

[From the abstract]

   Some BFD implementations may be restricted to only support several
   interval values.  When such BFD implementations speak to each other,
   there is a possibility of two sides not being able to find a common
   interval value to run BFD sessions.

   This document defines a small set of interval values for BFD that we
   call "Common intervals", and recommends implementations to support
   the defined intervals.  This solves the problem of finding an
   interval value that both BFD speakers can support while allowing a
   simplified implementation as seen for hardware-based BFD.  It does
   not restrict an implementation from supporting more intervals in
   addition to the Common intervals.

: Working Group Summary:
: Was there anything in WG process that is worth noting? For example, was
: there controversy about particular points or were there decisions where
: the consensus was particularly rough?

Discussion in the working group among known implementors of BFD was
relatively quiet but supportive of this document.  The only discussion
that generated any significant amount of "noise" was the discussion of
whether these well known common intervals should have an IANA registry
to permit the maintenance of this document without requiring a RFC
revision.  The consensus of that discussion was that an IANA registry
was not desired.

: Document Quality:
: Are there existing implementations of the protocol? Have a significant
: number of vendors indicated their plan to implement the specification?
: Are there any reviewers that merit special mention as having done a
: thorough review, e.g., one that resulted in important changes or a
: conclusion that the document had no substantive issues? If there was a
: MIB Doctor, Media Type or other expert review, what was its course
: (briefly)? In the case of a Media Type review, on what date was the
: request posted?

Multiple implementations support the full range of documented values in
either hardware or software, depending on the implementation.  The only
value that doesn't have very wide support is the 3.3ms value, but
support for this value seems to be becoming more common.

: Personnel:
: Who is the Document Shepherd? Who is the Responsible Area Director?

Document Shepherd: Jeffrey Haas
Responsible Area Director: Adrian Farrel

: (3) Briefly describe the review of this document that was performed by
: the Document Shepherd. If this version of the document is not ready for
: publication, please explain why the document is being forwarded to the

A thorough review of this document was done by the shepherd and the
document is judged to be of good quality and ready for publication.
Prior versions of this document were previously polled against known
implementations ot find out if the intervals present in this document
were supported.

: (4) Does the document Shepherd have any concerns about the depth or
: breadth of the reviews that have been performed?


: (5) Do portions of the document need review from a particular or from
: broader perspective, e.g., security, operational complexity, AAA, DNS,
: DHCP, XML, or internationalization? If so, describe the review that took
: place.


: (6) Describe any specific concerns or issues that the Document Shepherd
: has with this document that the Responsible Area Director and/or the
: IESG should be aware of? For example, perhaps he or she is uncomfortable
: with certain parts of the document, or has concerns whether there really
: is a need for it. In any event, if the WG has discussed those issues and
: has indicated that it still wishes to advance the document, detail those
: concerns here.

There are no such concerns.

: (7) Has each author confirmed that any and all appropriate IPR
: disclosures required for full conformance with the provisions of BCP 78
: and BCP 79 have already been filed. If not, explain why?

This document simply notes common intervals that may be used with BFD
(RFC 5880) sessions.  No new IPR would be relevant.

: (8) Has an IPR disclosure been filed that references this document? If
: so, summarize any WG discussion and conclusion regarding the IPR
: disclosures.

Not applicable.

: (9) How solid is the WG consensus behind this document? Does it
: represent the strong concurrence of a few individuals, with others being
: silent, or does the WG as a whole understand and agree with it?

Generally good support among known implementors of the protocol.  As is
typically the case for the BFD working group, a small core group is
responsible for the majority of the review and also the text.

: (10) Has anyone threatened an appeal or otherwise indicated extreme
: discontent? If so, please summarise 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.)


: (11) Identify any ID nits the Document Shepherd has found in this
: document. (See and the Internet-Drafts
: Checklist). Boilerplate checks are not enough; this check needs to be
: thorough.

The draft checks clean.

: (12) Describe how the document meets any required formal review
: criteria, such as the MIB Doctor, media type, and URI type reviews.

Not applicable.

: (13) Have all references within this document been identified as either
: normative or informative?


: (14) Are there normative references to documents that are not ready for
: advancement or are otherwise in an unclear state? If such normative
: references exist, what is the plan for their completion?


: (15) Are there downward normative references references (see RFC 3967)?
: If so, list these downward references to support the Area Director in
: the Last Call procedure.


: (16) Will publication of this document change the status of any existing
: RFCs? Are those RFCs listed on the title page header, listed in the
: abstract, and discussed in the introduction? If the RFCs are not listed
: in the Abstract and Introduction, explain why, and point to the part of
: the document where the relationship of this document to the other RFCs
: is discussed. If this information is not in the document, explain why
: the WG considers it unnecessary.

No such changes.

: (17) 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 protocol extensions that the document makes
: are associated with the appropriate reservations in IANA registries.
: Confirm that any referenced IANA registries have been clearly
: identified. Confirm that newly created IANA registries include a
: detailed specification of the initial contents for the registry, that
: allocations procedures for future registrations are defined, and a
: reasonable name for the new registry has been suggested (see RFC 5226).

As described above, no new requests are made to IANA.

: (18) List any new IANA registries that require Expert Review for future
: allocations. Provide any public guidance that the IESG would find useful
: in selecting the IANA Experts for these new registries.


: (19) Describe reviews and automated checks performed by the Document
: Shepherd to validate sections of the document written in a formal
: language, such as XML code, BNF rules, MIB definitions, etc.

Not applicable.

-- Jeff