RTP Control Protocol (RTCP) Extended Report (XR) for RLE of Discarded Packets
draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-09

[Ballot comment]
Thanks for solving my DISCUSS.
There are no guidelines yet on the performance metrics naming convention. This will be discussed in the IPPM WG, meeting right now.  No sure yet what the exact guidelines will be, but maybe it's not a good idea to have parentheses in the performance metric name.
      *  Metric Name: Run-length encoding (RLE) of Discarded RTP Packets Metric.

A RFC-editor note would solve this.

Regards, Benoit

[Ballot discuss]
DISCUSS:
The performance metrics review done by Alan Clark highlighted many points. Some are editorial, but one is a DISCUSS level type of feedback:the lack of the RFC 6390 template.
The ongoing discussion is going in the right direction (Thanks Varun), and I've even seen a temp draft version.
However, it doesn't contain the RFC 6390 template yet.

[Ballot comment]
- draft-ietf-xrblock-rtcp-xr-jb was changed so that all occurrences of "jitter buffer" was changed to "de-jitter buffer". A reference to RFC5481 was also given. For consistency reasons, you should do the same.
- expand "RR statistics. "

[Ballot comment]

I don't agree with the assertion in section 7 -
sometimes more precision is in fact enough to cause a
security issue, so the statement is just wrong. Was
security really considered?

The secdir review [1] also raises an interesting
question, about which we've planned to chat in
Berlin.

[1] http://www.ietf.org/mail-archive/web/secdir/current/msg04048.html

[Ballot comment]
C1. In Section 3: You say that this is the same format as in RFC 3611, when in reality it's different -- it adds the E flag.  Suggest:
OLD: "blocks in [RFC361]."
NEW: "blocks in [RFC361], with the addition of the "E" flag to indicate the reason for discard."

C2. In Section 3: In RFC 3611, the reserved bits MUST be set to zero.  Wy is it only a SHOULD here?

C3. In Section 3: The following phrase seems backwards: "These reserved bits SHOULD be set to zero by receivers and MUST be ignored by senders"  I realize that you're talking about *media* senders and receivers, but in context, this seems wrong.  Suggest reversing, so that you talk about the sender/receiver of the XR block.  That is also how RFC 3611 is written.

C4. The Interval Metric flag has defined meanings for the values 10, 01, and 11.  Please note what the meaning is when it has the value 00, or to forbid this value (MUST be one of 10, 01, or 11).

[Ballot comment]
Section 2: "...and indicate requirement levels for compliant implementations." What does that mean? 2119 defines the terms specifically to be used only when necessary for interoperability. To use them to indicate compliance requirements is to do something different than 2119 defines. Why was this added to the boilerplate?

Section 3: I agree with Spencer that the two "SHALL"s in the first paragraph need to be removed.

  rsvd (3 bits): These reserved bits SHOULD be set to zero by receivers
  and MUST be ignored by senders.

Shouldn't both statements be MUST? Is there a reason that a receiver would ever set it to other than 0?

  The 'E' bit MUST be set to '1' if the chunks represent packets discarded
  due to too early arrival and MUST be set to '0' otherwise.

These are definitions, not requirements. Nobody would choose to do differently. Instead: "When the 'E' bit is set to '1', it indicates that the chunks represent packets discarded due to early arrive. Otherwise, the 'E' bit is set to '0'."

The same sorts of things appear in section 4, and should be corrected there too.

Section 6: "The parameter 'discard-rle' MUST be used". Instead say, "The parameter 'discard-rle' is used".

[Ballot discuss]
This discuss point will be amazingly easy to resolve. It's either a one-word cut and paste error, or I don't understand RTCP-XR.

In 5.1.  Reporting Node (Receiver)

  Transmission of RTCP XR Discard RLE Reports is up to the discretion
  of the receiver, as is the reporting granularity.  However, it is
  RECOMMENDED that the receiver signals all discarded packets using the
  method defined in this document.  If all packets over a reporting
  period were lost, the receiver MAY use the Discard Report Block
  [I-D.ietf-xrblock-rtcp-xr-discard] instead.

Is this "all packets were lost", or "all packets were discarded"? Doesn't RFC 3611 treats packet loss and packet discard as two different things? That's the way I understood the third paragraph in the Introduction.

[Ballot comment]
In 3.  XR Discard RLE Report Block

  The XR Discard RLE report block uses the same format as specified for
  the loss and duplicate report blocks in [RFC3611].  Figure 1
  describes the packet format.  The fields "BT", "T", "block length",
  "SSRC of source", "begin_seq", and "end_seq" SHALL have the same
  semantics and representation as defined in [RFC3611].  The "chunks"
  encoding the run length SHALL have the same representation as in
  RFC3611, but encode discarded packets.

I don't think either SHALL is an RFC 2119 SHALL, but this text works just fine if you omit both SHALLs ...

[Ballot comment]
I have no objection to this document, and just one non-blocking comment:
I find the reference to "receiver" and "sender" (in the descriptions of the reserved bits in Sections 3 and 4, and in Section 5, especially 5.2) to be confusing.  The problem is that the media receiver is sending the report, and the media sender is receiving it, and the sense can easily get tangled.

I suggest always using "media sender" and "media receiver", rather than just "sender" and "receiver", and explicitly saying that the media receiver generates these reports and that the media sender consumes them.  Then stick with "generate" and "consume" to avoid confusion with "send" and "sender", and so on.

Does that make sense?

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-05. 
Authors should review the comments and/or questions below.  Please report any inaccuracies and respond to any questions as soon as possible.

We understand that, upon approval of this document, there are two actions which we must complete.

First, in the RTCP XR Block Type subregistry of the RTP Control Protocol Extended Reports (RTCP XR) Block Type Registry located at:

http://www.iana.org/assignments/rtcp-xr-block-types/rtcp-xr-block-types.xml

two new block types will be added as follows:

BT: [ TBD-at-registration ]
Name: Discard RLE Report Block
Reference: [ RFC-to-be ]

BT: [ TBD-at-registration ]
Name: Bytes Discarded Report Block
Reference: [ RFC-to-be ]

Second, in the RTP Control Protocol Extended Reports (RTCP XR) Session Description Protocol (SDP) Parameters Registry located at:

http://www.iana.org/assignments/rtcp-xr-sdp-parameters/rtcp-xr-sdp-parameters.xml

two new SDP parameters will be registered as follows:

Parameter: discard-rle
Reference: [ RFC-to-be ]

Parameter: discard-bytes
Reference: [ RFC-to-be ]

We understand that these are the only actions required 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.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (RTP Control Protocol (RTCP) Extended Reports (XR) for Run Length Encoding (RLE) of Discarded Packets) to Proposed Standard


The IESG has received a request from the Metric Blocks for use with
RTCP's Extended Report Framework WG (xrblock) to consider the following
document:
- 'RTP Control Protocol (RTCP) Extended Reports (XR) for Run Length
  Encoding (RLE) of Discarded Packets'
  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 2013-07-01. 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.

Abstract


  The RTP Control Protocol (RTCP) is used in conjunction with the Real-
  time Transport Protocol (RTP) in to provide a variety of short-term
  and long-term reception statistics.  The available reporting may
  include aggregate information across longer periods of time as well
  as individual packet reporting.  This document specifies a per-packet
  report metric capturing individual packets discarded from the jitter
  buffer after successful reception.




The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-xrblock-rtcp-xr-discard-rle-metrics/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-xrblock-rtcp-xr-discard-rle-metrics/ballot/


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

(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 document is being requested as a Standards Track RFC.

The document defines one new Extended Report (XR)
Report Block [RFC 3611] and standards track is appropriate for this document.

Standards Track is indicated in the title page.

(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 draft defines a new block type to augment those defined in
[RFC3611] for use in a range of RTP applications. The new block type
supports the reporting of the per-packet report metric capturing individual
packets discarded from the jitter buffer after successful reception.


Working Group Summary

There were several points of debate within the working group; however,
none were particularly rough and authors and commentators came up
with the text that resolves any issues thus consensus was achieved in
all cases.


Document Quality

This document has been reviewed by numerous people within
XRBLOCK and through two rounds of WGLCs the document
resolved any outstanding issues.

The document has been reviewed by SDP directorate post WGLC
for SDP extensions defined, any issues raised were resolved.

The document has been submitted to performance metric
directorate for a review prior to this draft being submitted for
IESG review.

Personnel

Shida Schubert 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 IESG.

I have reviewed the last two iterations of this document, including providing
technical and editorial review comments during the WGLC reviews.
All of my comments and that of others provided during WGLC are addressed.

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

No.

(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.

(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.

There are 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.

Yes

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

No.

(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?

Yes, there is strong consensus.

(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 http://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

No concern..

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

No formal reviews are required for this document.

(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 (see RFC 3967)?
If so, list these downward references to support the Area Director in
the Last Call procedure.

No.

(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).

Appropriate reservations have been included for IANA registries.

(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.

(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.

None required.