As required by RFC 4858, this is the current template for the Document
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?
The intended status is Proposed Standard. This is correct, since the
document defines new SDP attributes and RTP payload types, and media
types. The intended status is indicated in 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:
This document provides extensions to the Session Description Protocol
(SDP) and the Real-time Transport Protocol (RTP) for enabling looping
of sent media. Media loopback is especially popular in ensuring the
quality of transport to the edge of a given VoIP, Real-time Text or
Video over IP service. The extension defined herein adds new SDP media
types and attributes, which enable establishment of media sessions
where the media is looped back to the transmitter. Such media sessions
will serve as monitoring and troubleshooting tools by providing the
means for measurement of more advanced VoIP, Real-time Text and Video
over IP performance metrics.
Working Group Summary
The first version of the document was available at the end of 2004.
Since that time, the working group has been discussing a number of
issues toward getting the consensus that is believed to be achieved in
The description of a latching mechanism to traverse NATs and firewalls
was discussed and decided to be removed from the actual document in
favor of standard NAT traversal techniques such as ICE/STUN/TURN.
At least four implementations of this functionality are known. Four
other vendors have indicated they plan to implement it.
The document was WGLCed on version 16. Additionally, the PAYLOAD WG
also conducted a thorough review of the same 16 version. As a result of
these reviews, 34 changes were requested by, among others, Tolga
Asveren, Dan Wing, Emil Ivov, Flemming Andreasen, and Miguel A. Garcia.
These comments were subsequently introduced into versions 17 and 18. A
new WGLC was issued on version 18, bringing a new set of comments by
Flemming Andreasen, Magnus Westerlund, and Gunnar Hellstrom. These were
addressed in version 19.
At least Magnus Westerlund and Flemming Andreasen did a thorough review
of the document as part of the WGLC on version 18.
Version 18 was sent to the ietf-types mailing list for review on April
4, 2012. Bjorern Hoehrmann and Magnus Westerlund posted comments that
were addressed in version 19.
Who is the Document Shepherd? Who is the Responsible Area
Miguel A. Garcia is the Document Shepherd. Gonzalo Camarillo is the
Responsible Area Director
(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 Document Shepherd reviewed at least versions 16 and 18, as part of
the WGLC process. Changes introduces upto version 22 have been tracked by
the Document Shepherd. It is believed that this version of the document
is ready for publication.
(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?
No concerns. The document has got substantial and deep reviews throughout
its extended lifetime.
(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
The document creates two new RTP payload formats for achieving the
loopback functionality. Due to this, the document has been reviewed in
the PAYLOAD WG. In particular, version 16 suffered a thorough review in
the PAYLOAD mailing list.
The registration of new media types have been reviewed by the ietf-types
(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
There are no such 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.
There are no IPR disclosures associated to this document. Authors have
confirmed that no such IPR has
(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
No IPR disclosure has been filed so far.
(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 seems to be strong consensus on the current document by the WG,
which seems to understand and agree with it.
(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 such threat has been disclosed.
(11) Identify any ID nits the Document Shepherd has found in this
document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
ID nits is reporting no warnings or errors on version 22.
(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.
The document has been reviewed in the ietf-types mailing list, due to the
inclusion of a new media types.
(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 completion?
All the normative references are made towards published 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.
There are no downward normative references.
(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.
The publication of this document will not change the status of any
(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 Shepherd has reviewed the IANA considerations section and it
is believed to be correct and in line with the body fo the document.
The document requests three new SDP attributes to be registered. The
registration follows the template in RFC 4566 for registration of new
Additionally, the document request the registration of 8 new media types.
These registration follow the template in RFC 4288 and have been reviewed
by the ietf-types mailing list.
(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 IANA registries are defined by this document.
(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.
BNF rules have been checked against the Bap ABNF parser.