Transmission Time Offsets in RTP Streams
draft-ietf-avt-rtp-toffset-07

[Ballot comment]
I would note that the recommended RTCP packet type 195 is not from the first choice range established by the approval of draft-ietf-rtp-and-rtcp-mux some time ago. The value is from the second range and not a problematic one.

[Ballot comment]
(1) I was amused when I read the security considerations.  It *is* hard to see how informative
offsets have any security implications, but I appreciate the effort!

I would recommend adding a sentence pointing to RFC 3550 for the core security
considerations.

(2) FYI, [hdrext] is now RFC 5285.  Perhaps that should be added to the RFC Editor Note.

IANA Last Call comments:

Action 1:

Upon approval of this document, the IANA will make the following
assignments in the "RTCP Control Packet types (PT)" registry at
http://www.iana.org/assignments/rtp-parameters

abbrev. name value Reference
------------ ----- ----------
IJ Extended inter-arrival jitter report TBD [RFC-avt-rtp-toffset-07]


Action 2:

[ IESG Note: Expert Review Required ]

Upon approval of this document, the IANA will make the following
assignments in the "RTP Compact Header Extensions" registry at
http://www.iana.org/assignments/rtp-parameters

Extension URI Description Contact  Reference
------------ ------------ ----------- ----------
toffset Transmission Time offsets ???
[RFC-avt-rtp-toffset-07]

We need to finalize the IANA registry in the hdrext document then update the text in section 5 and 7 of this document to match. Otherwise looks fine.

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?

Tom Taylor  is the Document Shepherd.
I have personally reviewed this version of the document and consider it ready for forwarding.

(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?

The draft began as a one-paragraph instance of an RTP header extension
contained in the early versions of draft-ietf-avt-rtp-hdrext. In July of
2006 a number of useful comments were received, in a dialogue that
concluded with the issuance of draft-ietf-avt-rtp-toffset-00.txt in
August. That drew a few more comments that were further addressed in a new
draft a couple of weeks later. The only further update before WGLC was to
match the change in the extension identifier mechanism specified in draft-
ietf-avt-rtp-hdrext. A few more comments were received by solicited review
during WGLC (thanks, Qiaobing and Ron) and the Document Shepherd
identified a couple of nits.

Given this history, the Document Shepherd feels that
the document has had adequate review.


(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?

No.

The topic dealt with by the draft, separation of contributions to delay
variation by the source and the intervening network, is very specifically
within the scope of the AVT Working Group. IPPM might have an interest
given its recent work on delay variation
(draft-morton-ippm-delay-var-as-02.txt), but was not consulted. The
Document Shepherd does not see this as a concern but has forwarded a note
to IPPM to have a look at the draft.

(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. Has an IPR disclosure related to this document been filed? If so, please include a reference to the disclosure and summarize the WG discussion and conclusion on this issue.

All OK.

(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?

Many of the WG's active members have addressed it. On that basis,
consensus appears to be strong.

(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.)

No.

(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 passes idnits. The following nits exist:
- extra 's' in esssentially' in the second paragraph of page 6
- the reference to hdrext needs to be up-versioned to -12
- in accordance with the IANA Considerations section of
draft-ietf-avt-rtp-hdrext-12.txt, the document must indicate that it
updates draft-ietf-avt-rtp-hdrext-12.txt

(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].

All OK.

(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 suggest a reasonable name for the new registry? See [RFC2434]. 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?

All OK except the third nit identified under (1.g).

(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?

Not applicable.

(1.k) 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 describes a method to inform RTP clients when RTP
packets are transmitted at a time other than their 'nominal'
transmission time. It also provides a mechanism to provide improved
inter-arrival jitter reports from the clients, that take into account
the reported transmission times.

Working Group Summary

This RTP header extension was first defined within draft-ietf-avt-rtp-hdrext
as an initial application of the RTP header extension mechanism that draft
defines. As a result of WG discussion in July, 2006, it was moved to a
separate draft. Additional discussion resulted in further changes up through
Working Group Last Call. There is a strong Working Group consensus in favour
of the present document.

Document Quality

Solicited review comments from Qiaobing Xie and Ron Frederick provided a
final polish to the document.

Personnel

Tom Taylor is the Document Shepherd for this document?

Cullen Jennings is the Responsible Area Director?
No IANA expert is needed.