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Shepherd writeup
draft-holmberg-dispatch-received-realm

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?

  Standards Track. This document defines a protocol extension to SIP.

(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 specification defines a new Session Initiation Protocol (SIP) Via
  header field parameter, "received-realm", which allows a SIP entity acting
  as an entry point to a transit network to indicate from which adjacent
  upstream network a SIP request is received, using a network realm value
  associated with the adjacent network. This is needed in some network
  architectures to determine what processing should be applied to the request.

 Working Group Summary

  This document was brought to the DISPATCH working group in June of 2015.
  Several WG participants expressed interest in seeing the work progress to
  publication, and a follow-up conversation was held at IETF 93 to determine
  how the work should proceed.  The outcome of those conversations was that
  the mechanism being described was not in the charter of any existing working
  group, nor was it of broad enough applicability to warrant creating a new
  working group. The DISPATCH working group chose to dispatch this as
  sponsored by the area director.

 Document Quality

  This mechanism was introduced to address use cases identified by 3GPP for
  transit networks providing telecom-style services to SIP calls in an IMS
  context. The mechanism has been cited by 3GPP's TS 24.229 and incorporated as
  part of its procedures since March 2015. This presumably will lead to broad
  implementation of the mechanism by IMS equipment vendors.

  The original mechanism did not contain any authentication for information that
  was subsequently used for service processing. In response to security
  concerns, raised by Adam Roach and Richard Barnes, the mechanism was expanded
  to incorporate a JWS-based authentication of the realm being asserted.

 Personnel

    Adam Roach is the document shepherd. Ben Campbell is the area director
    sponsoring publication.

(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.

  As part of the final document write-up, the shepherd performed a
  front-to-back read of version -04 of the document, which uncovered numerous
  editorial and one major technical issue. The shepherd subsequently reviewed
  the diffs for the -05 version, which cured the technical issue, and the diffs
  for the -06 version, which addressed the editorial issues. The shepherd
  believes that the document is now implementable, serves its intended goal, and
  has reasonable security properties.

  This belief is somewhat tempered by the fact that the flaws uncovered during
  the -04 review were numerous and obvious, such that some large portion of them
  would have been noticed by other reviewers. It is not unreasonable to assume
  that this document has been read almost exclusively by the authors and the
  shepherd at this point. As a consequence, the shepherd encourages the IESG
  to perform an exceptionally deep review of the document and its described
  mechanism.

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

  While the document did have substantial support in DISPATCH, and the
  mechanism appears to be of great importance to the 3GPP, the number of
  reviews that have been performed have been underwhelming. While the document
  has undergone several revisions based on the document shepherd's input,
  there are technology areas -- specifically, the use of JWTs -- that lie
  outside his expertise. The document calls for registration of new JWT
  values, which require expert review. This review will presumably uncover any
  showstopper flaws in this area.

(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.

  As hinted at above, dedicated review by a party familiar with JWS and JWT is
  likely warranted.

(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 interested community has
discussed those issues and has indicated that it still wishes to advance
the document, detail those concerns here.

  The version of the document cited by 3GPP, which is the main driver for this
  work, is a much earlier version that was brought to the SIPCORE working group.
  It is possible that publication of the newer mechanism, with its security
  features, will not necessarily result in an update of the 3GPP specifications;
  and, if it does, that such an update may not necessarily result in
  implementations being upgraded to the secure mechanism.

(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.

  They have.

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

  There are no filed IPR disclosures.

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

  As mentioned above, feedback on the specific mechanism has been very sparse,
  and generally consisted of nonspecific support for the mechanism without any
  technical discussion.

(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.)

  There has been no displeasure, strong or otherwise, expressed regarding this
  mechanism.

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

  There are no legitimate nits; however, in checking through the checklist at
  <https://www.ietf.org/id-info/checklist.html>, the shepherd discovered
  several outdated requirements involving IPR-related boilerplate (cf. section
  2.2 of that document, bullets 10 through 12).  As noted in
  draft-bradner-rfc3979bis-08 section 13, such boilerplate has not been a
  requirement since the relevant provisions were moved into the Trust Legal
  Provisions in 2009.

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

  Registration of JWT fields with IANA requires expert review. This will take
  place during the IANA registration phase of publication.

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

  Yes.

(14) Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state?

  No such references exist.

(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.

  There are no downrefs: all normative references -- aside from RFC 2119 --
  are standards track.

(16) Will publication of this document change the status of any existing
RFCs?

  No.

(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).

  The IANA registrations in the document are consistent with the text,
  and clearly identify the appropriate registry. The JWT registration table
  currently lists both RFCs and sections within the RFC, which is unusual.
  This document does not include section numbers in its registration.

(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.

  This document does not establish any new IANA registries.

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

  The ABNF has been validated to be syntactically correct using Chris Newman's
  ABNF checker at <http://www.apps.ietf.org/node/12>
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