[Ballot comment]
There is one use of normative language but no rfc2119 boilerplate:

"RtpStreamId and RepairedStreamId MUST contain only alphanumeric characters."

I would actually recommend to add more normative language (and the boilerplate), e.g.:

" To be clear: the value carried in a RepairedRtpStreamId MUST
  match the RtpStreamId value from another RTP stream in the same
  session.  For example, if a source RTP stream is identified by
  RtpStreamId "A", then any redundancy RTP stream that repairs that
  source RTP stream will contain a RepairedRtpStreamId of "A" (if this
  mechanism is being used to perform such correlation).  These
  redundant RTP streams MAY also contain their own unique RtpStreamId."

[Ballot comment]
In this text from the Introduction,

  RTP sessions frequently consist of multiple streams,
 
would it be possible to add a word or two explaining why this happens? If it's true that this happens because multiple media types, or codecs, or ... are in use in the same RTP session, that's the level of detail I'm thinking about.

In this text:

  At the same time, when redundancy RTP streams are in use,
 
could you provide a reference for redundancy RTP streams? I'm guessing this is using RFC 7198, but that's just a guess.

I was impressed that you included this,

  These
  redundant RTP streams may also contain their own unique RtpStreamId.
 
but (of course) started wondering why you'd do that - can the RtpStreamId for a redundancy RTP stream appear as a RepairedRtpStreamId for a third RTP stream? Or is there some other reason to assign an RtpStreamId?

(Via drafts-lastcall-comment@iana.org): IESG/Authors/WG Chairs:

IANA has completed its review of draft-ietf-avtext-rid-06.txt. If any part of this review is inaccurate, please let us know.

IANA has a question about one of the actions requested in the IANA Considerations section of this document.

IANA understands that, upon approval of this document, there are four actions which IANA must complete.

First, the authors request the registration of "the RtpStreamId SDES item to the IANA "RTCP SDES item types" registry" in section 4.1 of the current document.

IANA Question --> Do the authors intend that the registration for section 4.1 take place in the RTP SDES Item Types registry located at: [ https://www.iana.org/assignments/rtp-parameters/ ]? IANA is unable to locate the "RTCP SDES item types" registry. If not, could the authors provide the location (URI) for the registration.

Second, in section 4.2 of the current draft, the authors once again refer to the "RTCP SDES item types" registry.

IANA Question --> Do the authors intend that the registration for section 4.2 take place in the RTP SDES Item Types registry located at: [ https://www.iana.org/assignments/rtp-parameters/ ]? IANA is unable to locate the "RTCP SDES item types" registry. If not, could the authors provide the location (URI) for the registration.

Third, in the RTP SDES Compact Header Extensions subregistry of the Real-Time Transport Protocol (RTP) Parameters registry located at:

https://www.iana.org/assignments/rtp-parameters/

a single new header extension is to be registered as follows:

Extension URI: urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
Description: RTP Stream Identifier
Contact: adam@nostrum.com
Reference: [ RFC-to-be ]

Fourth, also in the RTP SDES Compact Header Extensions subregistry of the Real-Time Transport Protocol (RTP) Parameters registry located at:

https://www.iana.org/assignments/rtp-parameters/

another new header extension is to be registered as follows:

Extension URI: urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-sream-id
Description: RTP Repaired Stream Identifier
Contact: adam@nostrum.com
Reference: [ RFC-to-be ]

IANA understands that the four actions above are the only ones required to be completed upon approval of this document.

Note:  The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is only to confirm what actions will be performed. 

Thank you,

Sabrina Tanamal
IANA Specialist
ICANN

The following Last Call announcement was sent out:

From: The IESG <iesg-secretary@ietf.org>
To: "IETF-Announce" <ietf-announce@ietf.org>
CC: ben@nostrum.com, avtext@ietf.org, jonathan@vidyo.com, avtext-chairs@ietf.org, draft-ietf-avtext-rid@ietf.org, "Jonathan Lennox" <jonathan@vidyo.com>
Reply-To: ietf@ietf.org
Sender: <iesg-secretary@ietf.org>
Subject: Last Call: <draft-ietf-avtext-rid-06.txt> (RTP Stream Identifier Source Description (SDES)) to Proposed Standard

The IESG has received a request from the Audio/Video Transport Extensions
WG (avtext) to consider the following document:
- 'RTP Stream Identifier Source Description (SDES)'
  <draft-ietf-avtext-rid-06.txt> as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2016-08-12. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

This document contains a normative reference to RFC 7656,
which is an informational RFC.

Abstract

  This document defines and registers two new RTCP SDES items.  One,
  named RtpStreamId, is used for unique identification of RTP streams.
  The other, RepairedRtpStreamId, can be used to identify which stream
  a redundancy RTP stream is to be used to repair.

The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-avtext-rid/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-avtext-rid/ballot/

No IPR declarations have been submitted directly on this I-D.

The document contains these normative downward references.
See RFC 3967 for additional information:
    rfc7656: A Taxonomy of Semantics and Mechanisms for Real-Time Transport Protocol (RTP) Sources (Informational - IETF stream)
Note that some of these references may already be listed in the acceptable Downref Registry.

My AD Evaluation:

Minor Comments:

- 4.3, last paragraph (and similar text in other registrations)

The first sentence is only guaranteed true if the implementation follows the guidance in 3.3. That says “strongly encouraged”. Maybe it should say something stronger?  (Or mention the condition here?)

- 6: Did you actually mean to acknowledge a co-author? (Peter)

Editorial Comments and Nits:

- Please expand first mention of "SDES" in both the abstract and body.

- 5, 2nd paragraph:
s/ impelementors / implementors ; unless you meant "impalementors". :-)

Also, does _this_ document strongly encourage encryption, or is that general encouragement from elsewhere that can be cited?

-5, 3rd paragraph:
s/exchange/change

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?

Proposed Standard; two new RTP Source Description and header extension
items are defined, for which interoperability will be necessary.

(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 document defines and registers two new RTCP Source Description
  items.  One, named RtpStreamId, is used for unique identification
  of RTP streams.  The other, RepairedRtpStreamId, can be used to
  identify which stream a redundancy RTP stream is to be used to
  repair.  It also defines and registers corresponding RTP Header
  Extension Elements.

Working Group Summary

  The document went through an initial last call, during which there
  were some objections to the design.  The authors and the objectors
  met together at the Buenos Aires IETF meeting, and worked out a
  slightly altered design which satisfied everyone.  A second last
  call produced only minor requests for changes, which were
  addressed, and several people confirmed that they had no issues
  with the draft.

Document Quality

  The document was reviewed by several AVText members, which resulted
  in the current design.  The mechanism defined by the document is
  expected to be mandated by WebRTC.  It is already implemented in
  Firefox and is planned to be implemented in Chrome.

Personnel

  The document Shepherd is Jonathan Lennox.  The Responsible Area
  Director is Ben Campbell.

(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 read the submitted version of the document
fully, as well as reviewing and commenting on several earlier versions
of the document.

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

This document got good review by multiple people from AVText and all
comments were addressed.

(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.

No broader reviews are needed.

(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.

No concerns.

(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.

All the authors have indicated they no of know relevant IPR on this
document.

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

No IPR Disclosures have been filed.

(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? 

Most of the group's most active (and expert) participants have
indicated agreement with the document's final design.  No disagreement was
indicated.

(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.)

No.

(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.

https://www.ietf.org/tools/idnits?url=https://www.ietf.org/archive/id/draft-ietf-avtext-rid-05.txt

There is one downref; see (15) below.

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

No formal review needed.

(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? If such normative
references exist, what is the plan for their completion?

No.

(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 is a normative reference to RFC 7656, "A Taxonomy of Semantics
and Mechanisms for Real-Time Transport Protocol (RTP) Sources", which
is an Informational RFC.  RFC 7656 defines terminology which this
document cites, rather than repeat.  RFC 7656 seems likely to be a
useful addition to the downref registry, as it was written to
standardize RTP terminology across IETF documents.

(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.

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 document defines two new entries for the "RTCP SDES item types"
registry.  This registry is Specification Required or Expert Review.
The required information is included.  It also defines two
corresponding entries in the "RTP SDES Compact Header Extensions"
sub-registry, which is Expert Review. All the required information is
included.

(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.

No new registries are defined.

(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.

No formal language is used in the document.