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Shepherd writeup

Document:  URNs for the Alert-Info Header Field of the Session
Initiation Protocol (SIP)

	(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?

Proposed Standard.

The relevant parts of the definition of "Proposed Standard", given in
RFC 2026 and reiterated in RFC 6410, are:

   A Proposed Standard specification is generally stable, has resolved
   known design choices, is believed to be well-understood, has received
   significant community review, and appears to enjoy enough community
   interest to be considered valuable.

   Usually, neither implementation nor operational experience is
   required for the designation of a specification as a Proposed
   Standard.  However, such experience is highly desirable, and will
   usually represent a strong argument in favor of a Proposed Standard

   A Proposed Standard should have no known technical omissions with
   respect to the requirements placed upon it.

The working group believes that all known design issues have been
resolved, and that the design satisfies all of the stated requirements
(listed in section 5), as well as the standards for SIP and for URN

This document also updates RFC 3261 by permitting the Alert-Info
header to appear in all non-100 provisional SIP responses.

Deutsche Telekom has indicated that they intend to implement this document.

One particular URN <urn:alert:service:normal> that is defined in this
document is referenced in draft-ietf-bliss-shared-appearances-15,
which is in the RFC Editor queue (and is itself Standards Track).

The "Standards Track" status is indicated on 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:

	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

The Session Initiation Protocol (SIP) supports the capability to
provide a reference to a specific rendering to be used by the UA when
the user is alerted.  This is done using the Alert-Info header field.
However, providing a reference (typically a URL) addresses only a
specific network resource with specific rendering properties.  This
document defines a new namespace of URNs for use in Alert-Info header
fields.  The URNs are defined to describe characteristics of the
incoming call, characteristics of how the call is being handled at the
callee, and rendering characteristics of the desired signal.  The URNs
can be combined to provide complex descriptions of the intended
signal.  Provisions are made for private extensions that can describe
additional signal characteristics and additional subcategorization of
standardized characteristics.  Detailed resolution rules are provided
to ensure that a renderer provides the best representation that it can
of the signaler's intention.

	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?

There is solid consensus in the SALUD WG of the value of this work and
the usefulness of this document.  A large set of requirements has been
identified to ensure that the proposed URNs can be used successfully
in converting existing telephone switches to operate using SIP.

	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?

Deutsche Telekom has indicated that they intend to implement this document.

An important review of the proposed URN namespace was done by Alfred
Hoenes, which identified a number of deficiencies in the original
proposal (which have been eliminated).  After revision, the URN
namespace definition was presented on the urn-nid mailing list, and no
objections were raised.

Many reviews have been done by the authors, and a final review by the
Document Shepherd, which convince the WG that there are no substantive
issues remaining.


	Who is the Document Shepherd? Who is the Responsible Area

The Document Shepherd is Christer Holmberg.

The Responsible Area Director is Richard Barnes.

	(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.

The Document Shepherd has reviewed the document. The document is well 
structured, and the defined extensions are clearly explained. The document 
also contains a requirements section, which helps readers to understand 
the background and justification to the chosen technical solution.

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

The Document Shepherd is satisfied with the review.

	(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 this document defines a new URN namespace, that namespace
definition must be reviewed.  Early in the process, Alfred Hoenes
provided invaluable feedback that allowed a number of important issues
to be corrected.  The current version of the namespace definition was
presented to the urn-nid mailing list, and no objections were made.

Internationalization considerations are listed in section 15.  Since
these URNs are not directly visible to users, internationalization
requirements are relatively modest.

The most important consideration is that a part of the
private-extension syntax includes representation of the domain name of
the private party defining the extension, so the private-extension
syntax must allow internationalized domain names.  This is provided
straightforwardly by allowing A-labels (per RFC 5890) (that is, the
"xn--..." form output by Punycode) to appear as a "domain name" part
of a URN.  Since this mechanism refers to the standardized handling of
internationalized domain names, no special review was given to it.

In addition, the URN system provides a way for a user agent to specify
that a ring tone or ringback tone be used that is customary in a
specific country.

	(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.

The Document Shepherd has no concerns regarding the technical content of 
the document. The Shepherd assumes that potential minor language nits 
will be taken care of by the RFC Editor.

	(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

Yes, all five authors have confirmed compliance with BCPs 78 and 79.
The confirmations are archived on the Salud WG mailing list.

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

As of 23 Feb 2014, none have been filed referencing this document.

	(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?

There is solid consensus in the SALUD WG of the value of this work and
this specific document.

	(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.)

The chairs and the Document Shepherd are not aware of such cases.

	(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.

The significant warnings found by the ID-Nits tool 2.13.00  are:

  Checking nits according to :

  -- The draft header indicates that this document updates RFC3261, but the
     abstract doesn't seem to directly say this.  It does mention RFC3261
     though, so this could be OK.

(This warning is incorrect, as the Abstract says "This document
normatively updates RFC 3261 ...".)

  Miscellaneous warnings:

     (Using the creation date from RFC3261, updated by this document, for
     RFC5378 checks: 2002-02-21)

  -- The document seems to contain a disclaimer for pre-RFC5378 work, and may
     have content which was first submitted before 10 November 2008.  The
     disclaimer is necessary when there are original authors that you have
     been unable to contact, or if some do not wish to grant the BCP78 rights
     to the IETF Trust.  If you are able to get all authors (current and
     original) to grant those rights, you can and should remove the
     disclaimer; otherwise, the disclaimer is needed and you can ignore this
     comment. (See the Legal Provisions document at for more information.)

(Section 4.2 of this document largely repeats three sentences of
section 20.4 of RFC 3261.

(We should check with the AD or perhaps the IESG to determine if the
rights for RFC 3261 have been granted.  Give the number of updates to
3261, it is likely that that has been done already, but I know of no
place to verify this.  If these writes have been granted by all
authors, the boilerplate version for the document can be changed from
"pre5378Trust200902" to "trust200902".)

  Checking references for intended status: Proposed Standard

     (See RFCs 3967 and 4897 for information about using normative references
     to lower-maturity documents in RFCs)

  == Missing Reference: 'RFCXXXX' is mentioned on line 1071, but not

(All instances of 'RFCXXXX' are to be replaced with the RFC number of
this document.)

(There is an informative reference to
draft-ietf-bliss-shared-appearances.  We expect the RFC Editor to
replace the draft name with its RFC number.
draft-ietf-bliss-shared-appearances is being held in the RFC Editor
queue solely because it references this document;
draft-ietf-bliss-shared-appearances and this document form a cluster.)

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

An important review of the proposed URN namespace was done by Alfred
Hoenes, which identified a number of deficiencies in the original
proposal (which have since been eliminated).  After revision, the URN
namespace definition was presented on the urn-nid mailing list, and no
objections were raised.

	(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

All normative references are RFCs.

	(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.


	(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.

This document normatively updates RFC 3261.  RFC 3261 is listed on the
title page header, and the update is outlined in the Abstract.  The
specifics of the update are provided in section 4.

	(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 Document Shepard has not identified any issues with the IANA 
considerations. The document creates a new IANA registry (Alert URN 
Identifiers). The rules and guidelines associated with registering 
new URN values (<alert-category> or <alert-indication>) are clearly 
described. The initial registry values, described in the document, 
follow the rules and guidelines.

	(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.

None of the new IANA registries specified by this document use Expert
Review for future allocations.

	(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.

The only section of the document that could be checked by automation
is the ABNF in section 7.  The ABNF was processed with the IETF ABNF
(, which
found no problems.