Connected Identity in the Session Initiation Protocol (SIP)
draft-ietf-sip-connected-identity-05

[Ballot comment]
The last paragraph of Section 2 provides an editorial note suggesting that there are some cases in which it would be plausible to provide identity in SIP responses. This sort of thing makes me a bit nervous.

IANA Last Call Comments:

Action #1:

Upon approval of this document, the IANA will make the
following assignments in the "Session Initiation
Protocol (SIP) Parameters" registry located at

http://www.iana.org/assignments/sip-parameters
sub-registry "Option Tags"



Name | Description | Reference |
------------+------------------------------------------+-----------+
from-change This option tag is used to indicate that
[RFC-sip-connected-identity-04]
a UA supports changes to URIs in From
and To header fields during a dialog.



We understand the above to be the only IANA Action for
this document.

PROTO Write-up

(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?

Keith Drage

The document has been reviewed and is ready for forwarding to 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?

Document history:
* draft-elwell-sip-connected-identity-00 was submitted October 2005 and
expired April 2005.
* draft-elwell-sip-connected-identity-01 was submitted 19th February
2006 and expired 23rd August 2006.
* draft-ietf-sip-connected-identity-00 was submitted 26th April 2006 and
expired 26th October 2006.
* draft-ietf-sip-connected-identity-01 was submitted 8th August 2006 and
expires 8th February 2007.
* draft-ietf-sip-connected-identity-02 was submitted 6th October 2006
and expires 6th April 2007.
* draft-ietf-sip-connected-identity-03 was submitted 9th January 2007
and expires 9th July 2007.
* draft-ietf-sip-connected-identity-04 was submitted 17th January 2007
and expires 21st July 1007.

WGLC was initiated in the SIP WG on draft-ietf-sip-connected-identity-01 on
4th September 2006 with comments requested by 18th September 2006.

Review was made and comments were received from: Cullen Jennings, Shida
Schubert, Francois Audet, Paul Kyzivat, Sietse van der Gaast (with an
indication that all had performed a full review of the draft. During the
course of the work comments have also been made by: Denis Alexeitsev, Ilan
Avner, Christer Holmberg, Frank Derks, Hans Person, Jonathan Rosenberg,
Rocky Wang, Shida Schubert, Roland Jesske, Georg Mayer, Fredrik Thulin, Bob
Penfield, Mike Hammer, Jeroen van Bemmel, Jon Peterson, Hisham Khartabil,
Martin Dolly, Cullen Jennings, Paul Kyzivat, David Oran, Feng Cao, Henry
Sinnreich, Lavis Zhou, Dan Wing, Eric Rescorla.

There have been two key issues in the discussion that have been resolved to
the satisfaction of the SIP working group, but which are worth mentioning
here:

* There was early discussion about whether the scope of the work should
be a complete solution to response identity, or whether it should just
cover connected identity. During the discussions, it was identified
that the complete solution to response identity was a near impossible
problem to solve. There is no general solution to authenticating a
response except in specific circumstances, i.e. when a TLS connection
exists to the UAS. There is also an issue of whether the response is
coming from a legitimate location, i.e. if the request had been
retargetted. There was a draft-cao-sip-response-identity which was
therefore not proceeded with.
* The document allows the changing of the From header field in a mid-
dialog request from that given in the initial request. There was
discussion on whether changing the value was allowed and whether the
lack of compatibility with the now obsoleted RFC 2543 was an issue. It
was agreed that this compatibility issue had been adequately addressed
when RFC 3261 was published. This has a corresponding impact on the To
header field in the other direction. This does not relate to changing
the To header field in a retargeted request.

(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 a security related document, the document has been reviewed by Eric
Rescorla (the security adviser to the SIP working group), and there are no
remaining unresolved issues.

(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.

The document defines a new SIP protocol extension for a particular purpose
in a form that has been used for many other extensions. The document
shepherd has no concerns with the 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 document has been well discussed by a significant number of members of
the working group (see answer in 1(b)).

(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.)

None indicated.

(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 has been reviewed against the guidelines in RFC 4485 and it is
believed that the document is conformant with those guidelines.

While the document defines a new SIP option tag, these have been performed
as a SIP working group item, and therefore this draft is in conformance with
RFC 3427.

The document passes ID-NITS (idnits 1.123).

(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 split its references into normative and informative
references. All the normative and informative references are published RFCs.
All the normative references are standards track documents.

(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 suggested a
reasonable name for the new registry? See
[I-D.narten-iana-considerations-rfc2434bis]. 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?

Section 6 of the document registers a new option-tag; the new option-tag is
defined elsewhere in the document. This registration is consistent with RFC
3261 which defines the registry and is also consistent with the current
format of the registry.

(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 contains no entries written in formal language. Section 5 of
the document makes use of encoded keys within a SIP message body, and these
have been automatically generated using the same tools as for RFC 4474.

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

Technical Summary

Because of retargeting of a Session Initiation Protocol (SIP) dialog-forming
request (changing the value of the Request-URI), the User Agent Server (UAS)
can have a different identity from that in the To header field. This
document provides a means for that User Agent (UA) to supply its identity to
the peer UA by means of a request in the reverse direction and for that
identity to be signed by an Authentication Service. The same mechanism can
be used to indicate a change of identity during a dialog, e.g., because of
some action in the Public Switched Telephone Network (PSTN) behind a gateway.
This document normatively updates RFC 3261 (SIP).

Working Group Summary

The document complements work already performed in RFC 4474 for
authenticated request identity, and forms an integral part of the chartered
work in this area. There is consensus in the working group to publish this
document.

Document Quality

The document has been well discussed by a significant number of members of
the working group.

Personnel

Keith Drage is the document shepherd for this document. Cullen Jennings is
the responsible Area Director.