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Shepherd writeup


As required by RFC4858, this is the current template for the Document Shepherd

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?


(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:

This describes a standards-track procedure for SCTP to support of failover when
working with a multi-homed SCTP end-point:

   SCTP supports multi-homing.  However, when the failover operation
   specified in RFC4960 is followed, there can be significant delay and
   performance degradation in the data transfer path failover.  To
   overcome this problem this document specifies a quick failover
   algorithm (SCTP-PF) based on the introduction of a Potentially Failed
   (PF) state in SCTP Path Management.

   The document also specifies a dormant state operation of SCTP.  This
   dormant state operation is required to be followed by an SCTP-PF
   implementation, but it may equally well be applied by a standard
   RFC4960 SCTP implementation.

   Additionally, the document introduces an alternative switchback
   operation mode called Primary Path Switchover that will be beneficial
   in certain situations.  This mode of operation applies to both a
   standard RFC4960 SCTP implementation as well as to a SCTP-PF

   The procedures defined in the document require only minimal
   modifications to the RFC4960 specification.  The procedures are
   sender-side only and do not impact the SCTP receiver.

Working Group Summary:

Document Quality:
The document is thought ready to publish.


Who is the Document Shepherd?
G Fairhurst (TSVWG Co-Chair)

Who is the Responsible Area Director?
Spencer Dawkins (TSV AD)

(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 IESG.

I have reviewed this document a number of times, and the requested improvements
in quality and readability have been incorporated. I am happy the final
document is ready to publish.

The feature specified by this document is implemented by multiple SCTP SW
implementations and furthermore that various variants of the solution have been
deployed in Telco signaling environments for several years with good results.

PF has been coded into FreeBSD, and plans to update to this spec.
Ericsson SW (supported in various forms for 5 years)
This feature is supported in Ericsson in-house SCTP SW implementation, and
available for use in other stacks.

It is partially implemented in Linux SCTP SW (July 2014) with the intent to

(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.


(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?

OK - Yoshifumi Nishida <>
OK - Preethi Natarajan <>
OK - Armando Caro <>
OK - P. Amer <>
OK - K. Nielsen <>

(OK means the authors have confirmed that they comply withe provisions).

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

None known.

(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?

The document received support from TSVWG.

This document has received appropriate review by the TSV WG: The document was
adopted by WG 26/6/2012. It has been reviewed by principal SCTP maintainers. A
WGLC concluded 19th November, 2014 and was followed by significant work to
improve the quality of the document and specification of the protocol. At the
end of this updates  the authors worked with people raising comments to confirm
the set of changes and a final 2 week WGLC in Sept 2015 confirmed acceptance of
the final document by the TSVWG.

(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.


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


(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


(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.


It was considered whether this updates the SCTP base specification RFC, but
after consideration by the WG it was concluded this is an optional extension
that should not update this spec. This seems in line with the update policy for

(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).

This document requires no actions from 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.