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Shepherd writeup

Request for Publication
Document: RTP-mixer formatting of multi-party Real-time text
Intended Status: Proposed Standard Document Shepard: Bernard Aboba

(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:

   Emergency call use of RFC 4103 "RTP Payload for Text Conversation"
   requires multi-party mixing.  Real-time text mixers for multi-party
   sessions need to identify the source of each transmitted group of
   text so that the text can be presented by endpoints in suitable
   grouping with other text from the same source, while new text from
   other sources is also presented in readable grouping as received
   interleaved in real-time.

   Enhancements for RFC 4103 real-time text mixing are provided in this
   document, suitable for a centralized conference model that enables
   source identification and rapidly interleaved transmission of text
   from different sources.  The intended use is for real-time text
   mixers and participant endpoints capable of providing an efficient
   presentation or other treatment of a multi-party real-time text
   session.  The specified mechanism builds on the standard use of the
   CSRC list in the RTP packet for source identification.  The method
   makes use of the same "text/t140" and "text/red" formats as for two-
   party sessions.

Working Group Summary:

WG Last Call of "RTP-mixer formatting of multi-party Real-time text" was
announced on November 25, 2020:

WGLC concluded on December 9, 2020.

Of the 6 participants responding to the WGLC, 3 supported Advancement to
Proposed Standard, and 3 respondents provided comments, which were addressed
by the author.

Document Quality:

Are there existing implementations of the protocol? Have a significant number
of vendors indicated their plan to implement the specification? Are there any
reviewers that merit special mention as having done a thorough review, e.g.,
one that resulted in important changes or a conclusion that the document had no
substantive issues? If there was a MIB Doctor, YANG Doctor, Media Type or other
expert review, what was its course (briefly)? In the case of a Media Type
review, on what date was the request posted?

There are no existing implementations of the specification.


Who is the Document Shepherd? Who is the Responsible Area Director?

Document Shepherd is Bernard Aboba. Responsible AD is Barry Leiba.

(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 document and provided comments here:

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

The specification has not been implemented yet, so it is possible that issues
could arise in implementation. This is more of a concern than for typical
AVTCORE documents, since this specification is likely to become a regulatory
requirement prior to advancing beyond Proposed Standard.

(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 does not raise any unique security, AAA, DNS, DHCP, XML or
internationalization issues. Since there are no implementations yet, it is
possible that operational complexity concerns will arise that have not been

(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.

During review, the question was raised as to whether the specification will
require development of an RTT mixer, or whether it could be made compatible
with existing conferencing servers implementing Selective Forwarding.

(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?


(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:

(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?

The document has been reviewed by people knowledgeable about emergency services
and the role of Realtime Text within those services. It has also had some
review from implementers of general communication services.

(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 appeal threats or extreme discontent expressed.

(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 thorough.

IDnits run on -13 shows no errors:

idnits 2.16.05

tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1351): Unexpected reference
format: '...         ...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1353): Unexpected reference
format: '...         ...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1355): Unexpected reference
format: '...         ...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1358): Unexpected reference
format: '...         ...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1361): Unexpected reference
format: '...         ...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1363): Unexpected reference
format: '...         ...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1365): Unexpected reference
format: '...         ...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1368): Unexpected reference
format: '...         ...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1689): Unexpected reference
format: '...    |[Bob...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1691): Unexpected reference
format: '...    |[Eve...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1694): Unexpected reference
format: '...    |[Bob...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1697): Unexpected reference
format: '...    |[Eve...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1698): Unexpected reference
format: '...    |[Bob...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1707): Unexpected reference
format: '...    |[Ali...'
tmp/draft-ietf-avtcore-multi-party-rtt-mix-13.txt(1714): Unexpected reference
format: '...    |[Ali...'

  Checking boilerplate required by RFC 5378 and the IETF Trust (see

     No issues found here.

  Checking nits according to

     No issues found here.

  Checking nits according to :

     No issues found here.

  Miscellaneous warnings:

     (Using the creation date from RFC4103, updated by this document, for
     RFC5378 checks: 2004-06-15)

  -- The document seems to lack a disclaimer for pre-RFC5378 work, but may
     have content which was first submitted before 10 November 2008.  If you
     have contacted all the original authors and they are all willing to grant
     the BCP78 rights to the IETF Trust, then this is fine, and you can ignore
     this comment.  If not, you may need to add the pre-RFC5378 disclaimer.
     (See the Legal Provisions document at for more information.)

     IETF Trust Legal Provisions of 28-dec-2009, Section 6.c(iii):
        This document may contain material from IETF Documents or IETF
        Contributions published or made publicly available before
        November 10, 2008.  The person(s) controlling the copyright in
        some of this material may not have granted the IETF Trust the
        right to allow modifications of such material outside the IETF
        Standards Process. Without obtaining an adequate license from the
        person(s) controlling the copyright in such materials, this
        document may not be modified outside the IETF Standards Process,
        and derivative works of it may not be created outside the IETF
        Standards Process, except to format it for publication as an RFC
        or to translate it into languages other than English.

  Checking references for intended status: Proposed Standard

     (See RFCs 3967 and 4897 for information about using normative references
     to lower-maturity documents in RFCs)

  -- Possible downref: Non-RFC (?) normative reference: ref. 'T140'

  -- Possible downref: Non-RFC (?) normative reference: ref. 'T140ad1'

     Summary: 0 errors (**), 0 flaws (~~), 0 warnings (==), 3 comments (--).

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

The document contains no MIBs or YANG modules and does not define media or URI
types. Section 3.20 does contain Offer/Answer examples which may benefit from
review by the SDP Directorate.

(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?

There is a normative reference to draft-ietf-mmusic-t140-usage-data-channel
which should be updated to RFC 8865.

(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

There are references to non-IETF specifications (T.140), but no down references
to IETF specifications.

(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 existing

(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 8126).

Section 10.1 of the document requests registration of the "rtt-mixer" sdp media
attribute.  There are no other IANA actions requested.

(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 requested.

(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, YANG modules, etc.

No formal languages used.

(20) If the document contains a YANG module, has the module been checked with
any of the recommended validation tools
( for syntax and
formatting validation? If there are any resulting errors or warnings, what is
the justification for not fixing them at this time? Does the YANG module comply
with the Network Management Datastore Architecture (NMDA) as specified in

No YANG modules.