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Shepherd writeup

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

(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

   Multimedia applications often suffer from packet losses in IP
   networks. In order to get a reasonable degree of quality in case of
   packet losses, it is necessary to have loss concealment mechanisms at
   the decoder. Video loss concealment is a range of techniques to mask
   the effects of packet loss in video communications.

   In some applications, reporting the information of receivers applying
   video loss concealment could give monitors or senders useful
   information on application QoE. One example is no-reference video
   quality evaluation. Video probes located upstream from the video
   endpoint or terminal may not see loss occurring between the probe and
   the endpoint, and may also not be fully aware of the specific loss
   concealment methods being dynamically applied by the video endpoint.
   Evaluating error concealment is important in the circumstance in
   estimating the subjective impact of impairments.

   This draft defines one new video loss concealment block type to
   augment those defined in [RFC3611] and [RFC7294] for use in a range
   of RTP video applications. The metrics defined in this draft belong
   to the class of transport-related terminal metrics defined in

Working Group Summary

  The XRBLOCK WG has a small but dedicated number of contributors. The I-D was
  attentively reviewed and improved by comments provided by contributors. There
  is strong consensus to advance the document to the IESG

Document Quality

 Representatives from a couple of vendors reported on plans to implement. The
 document was reviewed by the SDP and PMOL directorates, and comments made by
 these were addressed and changes incorporated.


  Dan Romascanu is the Shepherd, Alissa Cooper is the Responsible AD.

(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.

I read and reviewed the document in all its phases. This version is ready for
publication IMO.

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


(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.

The document was reviewed by the SDP and PM directorates.

(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.


(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.

The principal editor Rachel Huang confirmed. The co-editor Alan Clark did not

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


(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?

It represents the strong concurrence of a few individuals who are actively
participating in the WG with editing and reviews.

(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.)


(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

Running idnits results in no errors or warnings

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

(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?


(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.


(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).

A new RTCP XR block type value and a new RTCP XR SDP parameter are defined in
the IANA considerations section. The definitions are clear.

(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.


(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.