Publication requested for draft-ietf-sip-record-route-fix-06

We have requested publication of this WG effort as a BCP. I'd like to  
thank Nils for volunteering to serve as the draft shepherd, and for  
preparing most of the writeup below.

--
Dean Willis, SIP WG co-chair.


Writeup follows:


The SIP working group would like to request publication of draft-ietf-
sip-record-route-fix-06. This is a product of the SIP working group and
is intended for Best Current Practice status.

Nils Ohlmeier <[email protected]> will serve as the draft shepherd,
supported by SIP working group chair Dean Willis.

A write-up, prepared by Nils, is attached.

[This template version is dated September 17, 2008.]

(for draft-ietf-sip-record-route-fix-06)

     (1.a) Who is the Document Shepherd for this document? Has the
           Document Shepherd personally reviewed this version of the
           document and, in particular, does he or she believe this
           version is ready for forwarding to the IESG for publication?

The Document Shepherd for this document is Nils Ohlmeier. I have  read
this version of the draft and believe it is ready for forwarding to
the IESG for publication.

     (1.b) Has the document had adequate review both from key WG members
           and from key non-WG members? Does the Document Shepherd have
           any concerns about the depth or breadth of the reviews that
           have been performed?

This document has had in-depth reviews from working group members with
no concerns.

     (1.c) Does the Document Shepherd have concerns that the document
           needs more review from a particular or broader perspective,
           e.g., security, operational complexity, someone familiar with
           AAA, internationalization or XML?

As the document describes a best current practice which is widely
deployed and the document got several reviews there are no concerns.

     (1.d) Does the Document Shepherd have any specific concerns or
           issues 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. Has an IPR disclosure related to this document
           been filed? If so, please include a reference to the
           disclosure and summarize the WG discussion and conclusion on
           this issue.

I believe the described technique should be documented and I have no
concerns with the document.
There have been no IPR disclosures for this document.

     (1.e) 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 WG consensus appears to be strong.

     (1.f) 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
           entered into the ID Tracker.)

No one has expressed any discontent with this document.

     (1.g) Has the Document Shepherd personally verified that the
           document satisfies all ID nits? (See
           http://www.ietf.org/ID-Checklist.html and
           http://tools.ietf.org/tools/idnits/). Boilerplate checks are
           not enough; this check needs to be thorough. Has the document
           met all formal review criteria it needs to, such as the MIB
           Doctor, media type and URI type reviews?

The document shepherd has personally verified that this version of the
document satisfies all of the ID nits, bar a warning about legal
boilerplate about pre-RFC5378 work.

     (1.h) Has the document split its references into normative and
           informative? 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
           strategy for their completion? Are there normative references
           that are downward references, as described in [RFC3967]? If
           so, list these downward references to support the Area
           Director in the Last Call procedure for them [RFC3967].

The document has been split into normative and informative references.
All normative references are stable.

     (1.i) Has the Document Shepherd verified that the document IANA
           consideration section exists and is consistent with the body
           of the document? If the document specifies protocol
           extensions, are reservations requested in appropriate IANA
           registries? Are the IANA registries clearly identified? If
           the document creates a new registry, does it define the
           proposed initial contents of the registry and an allocation
           procedure for future registrations? Does it suggest a
           reasonable name for the new registry? See [RFC5226]. If the
           document describes an Expert Review process has Shepherd
           conferred with the Responsible Area Director so that the IESG
           can appoint the needed Expert during the IESG Evaluation?

This document has an IANA considerations section with no actions
for the IANA, which matches the body of the document.

     (1.j) Has the Document Shepherd verified that sections of the
           document that are written in a formal language, such as XML
           code, BNF rules, MIB definitions, etc., validate correctly in
           an automated checker?

SIP messages in examples have been manually checked and appear to be
valid.

     (1.k) 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
              Relevant content can frequently be found in the abstract
              and/or introduction of the document. If not, this may be
              an indication that there are deficiencies in the abstract
              or introduction.


Multi-homed SIP proxies (having two or more interfaces) raise special
requirements when handling SIP requests that have different ingress
and egress interfaces.  One technique that has been widely deployed is
to insert a single Record-Route header describing the egress interface.
When another request in the  same dialog then traverses the proxy in a
reverse direction, the proxy must edit the headers to reflect the new
egress interface. This document formalizes another technique that has
also been widely deployed and found to be simpler and more effective.
Using this technique, the proxy inserts two record-route headers, one
for the ingress interface and one for the egress interface. This keeps  
the
route symmetric, such that it can be traversed in the reverse direction
without requiring examination and editing by the proxy, thereby
reducing system complexity and processing load in the proxy.


           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?

The biggest discussion around this document was which status this  
document
should get. The working group decided to target for Best Current  
Practice
and against a normative update of RFC3261. Work on this document began  
in
March 2007 and the WGLC was held in July 2008.

           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?

This document specifically addresses an area of SIP that has been an
interoperability problem in the past. The SIPit interoperability
events have seen many problems in the area of Record-Route handling
in multi homed scenarios (including traversal between different sub
networks and changes of transport or IP protocol). The described
technique is widely deployed in several SIP proxies already.

This document has been reviewed by many participants over the lifetime
of the document, by the following members of the WG:

   - Francois Audet
   - Jonathan Rosenberg
   - Cullen Jennings
   - Paul Kyzivat
   - Robert Sparks
   - Nils Ohlmeier
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