Subject: [Sip] Draft shepherd writeup for draft-ietf-sip-sips

From: Dean Willis <[email-masked]>
Date: Wed, 23 Apr 2008 23:33:59 -0500

I seem to have lucked into the job of shepherding the SIPS draft  
through the IESG. This process is more or less documented at:

http://www3.tools.ietf.org/group/proto/home/

The first step is prepping the document for IESG submission. This  
entails giving it a read-through, running the idnots checker, looking  
for a few common errors, and so on. There's a checklist for the writeup.

The following is my first draft at the writeup. Please look through  
and see if there's anything you disagree with or you think I just got  
wrong.

I'll plan to send this into the IESG relatively soon.

Thanks!

---------------

Document Shepherd Write-Up for draft-ietf-sip-sips

This based on is template for the Document Shepherd Write-Up dated
February 1, 2007.

    (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 Dean Willis, current
co-chair of the SIP working group. He has reviewed this version of the
document and several previous versions in depth and believes this
version (outside of minor reference issues noted herein) 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?

The document has been extensively reviewed within the working group
and received extensive additional refinement from our security area
adviser Eric Rescorla. It entered working group last call as version
-05 on July 9, 2007 and was subsequently reviewed through three
iterations.

    (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?
No.

    (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.

This shepherd has no issues of this sort.

    (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?

This draft enjoys a relatively high level of working group
consensus. We've repeatedly revisited every issue until all known
significant issues (other than the fundamentals of underlying
complexity) have been resolved.

    (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.)

This shepherd is unaware of any evidence of extreme 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?

This shepherd has verified that the document satisfies all I-D
nits. Note that the idnits tool falsely reports a non-compliant IP
address -- the text it cites is actually a chapter-and-paragraph
reference to another document. Also noted is that this document
references both the obsolete RFC 2543 and current RFC 3261. This dual
reference is intentional, as it is the intent of this document to
clarify an issue with RFC 2543 that RFC 3261 also tried to clarify.

Note also that this document references draft-ietf-sip-outbound-11,
which is currently -13. The material referenced has not been affected
by these revisions, and publication of this document by the RF editor
will be blocked pending publication of draft-ietf-sip-outbound anyhow.

    (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 references are properly divided. There is a normative reference to
draft-ietf-sip-outbound that will probably delay this document.

    (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 [RFC2434].  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?

The IANA Considerations section is present and appears to be reasonable.

    (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?

The document appears to contain no sections specified in a formal  
language.

    (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.

Technical Summary:

This document updates RFC 3261 to provide clarifications and
guidelines concerning the use of the SIPS URI scheme in the Session
Initiation Protocol (SIP).  This document also provides a discussion
of possible future steps in specification.

The SIPS URI scheme was originally documented in RFC 3261, but
experience has shown that the specification therein is incomplete, and
that at least one use case that increased the complexity of the
specification (the "last hop exception") can be eliminated.

Several possible error conditions relating to mismatch of sips vs. sip
on sending and receiving ends exist. This documents adds new SIP error
codes to provide for the detection and correction of these error
conditions.

           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?

Working Group Summary:

There were several topics of significance that are worth noting.

The foremost is the deprecation of the "last hop exception" from RFC
3261. This exception allowed a proxy/registrar supporting SIPS to
relay requests received using SIPS on to user agent servers that did
not indicate support for SIPS. This increases the complexity of
implementations and weakens the end-to-end assurance of signaling
security provided by SIPS. After extensive debate, the working group
resolved to eliminate this exception and make SIPS fully
end-to-end. Doing so required extensive discussion and annotation on
what "end to end" means in the context of gateways to non-SIP
protocols.

Detection and correction of error conditions resulting where a UAC has
specified a SIPS request and the terminating UAS has not registered a
SIP contact, or where the UAC has specified a SIP request and the
terminating UAS has registered only a SIP contact was another problem
requiring extensive discussion. The "obvious" approach of using 400
class responses created problems when interacting with forking
proxies. The WG concluded on using two new 300-class SIP response
codes to enable request resolution in these scenarios.

During the process of developing this specification, the working group
began to converge on a new process for incrementally updating RFC
3261. As a precursor to this process, this specification contains an
appendix that provides explicit in-context changes to RFC 3261 as
required by this specification. The intent here is to reduce the
complexity of discussions at interoperability events.

           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?

There are several notable implementations of the specification at
varying levels of maturity. The SIPIt interop events have included
SIPS for some time, and the changes in this specification were in-part
driven by experiences at those interop events.

The document' Acknowledgements section cites numerous active
participants for providing detailed review.

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