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The proposers would like to request a 2-hour slot for a BOF in
Vancouver on the subject of RTP Congestion Control.<br>
<br>
The proposed acronym is RMCAT - RTP Media Congestion Avoidance
Techniques.<br>
<br>
Conflicts to avoid: RTCWEB, AVTCORE, MMUSIC, ICCRG, CODEC and any
video codec BOF, TCPM and relevant transport WGs<br>
<br>
Expected attendance: 60 persons.<br>
<br>
BOF agenda<br>
----------------<br>
Chairs: Randell Jesup and Harald Alvestrand<br>
<br>
Area: TSV<br>
Area directors: Wesley Eddy, Martin Stiemerling<br>
<br>
The following is a draft agenda, subject to modifications. Names are
tentative.<br>
Intro (Chairs - 5 min)<br>
Problem statement (Harald/Randell) - 25 min<br>
Covers existing protocols and their effect on low-delay streams.<br>
Addresses limiting the scope of this effort to a "probably solvable
problem".<br>
Includes a report from the IAB workshop on the same topic on
Saturday<br>
Context setting: BufferBloat & AQM (10 min) (Gettys)<br>
RRTCC draft (10 min) (Stefan)<br>
Describes existing proposal, Covering areas for improvement<br>
Alternative Solution (10 min) (?)<br>
Modified Cx-TCP?? Modified TFRC???<br>
Charter presentation, discussion (50 min)<br>
Next steps/conclusion (10 min)<br>
Total timeslot: 2 hours.<br>
<br>
WG charter (proposed)<br>
-------------------------------<br>
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RTP Media Congestion Avoidance Techniques (rmcat)<br>
<br>
Status: Proposed Working Group<br>
Last Updated: 2012-05-18<br>
<br>
Chair(s):<br>
TBD<br>
<br>
Transport Area Director(s):<br>
Wesley Eddy <a class="moz-txt-link-rfc2396E" href="mailto:wes@mti-systems.com"><wes@mti-systems.com></a><br>
<br>
Transport Area Advisor:<br>
Wesley Eddy <a class="moz-txt-link-rfc2396E" href="mailto:wes@mti-systems.com"><wes@mti-systems.com></a><br>
<br>
Mailing Lists: TBD (until establishment, we use
<a class="moz-txt-link-abbreviated" href="mailto:rtp-congestion@alvestrand.no">rtp-congestion@alvestrand.no</a>)<br>
<br>
Description of Working Group<br>
<br>
In today's current internet, part of the traffic is delivery of
interactive real time media, often in the form of sets of media
flows using RTP over UDP.<br>
There is no generally accepted congestion control mechanism for this
kind of data flow.<br>
With the deployment of applications using the RTCWEB protocol suite,
the number of such flows is likely to increase, especially
non-fixed-rate flows such as video or adaptive audio. There is
therefore some urgency in specifying one or more congestion control
mechanisms that can find general acceptance.<br>
<br>
The set of requirements for such an algorithm includes, but is not
limited to:<br>
* Low delay for the case where there is no competing traffic using
other algorithms<br>
* Fair share of bandwidth when there is competing traffic using
other algorithms<br>
* Effective use of signals like packet loss and ECN markings to
adapt to congestion<br>
<br>
The working group will:<br>
* Develop a clear understanding of the congestion control
requirements for RTP flows, and document deficiencies of existing
mechanisms such as TFRC with regards to these requirements<br>
* Determine if there is an appropriate means to define standard
RTP/RTCP extensions for carrying congestion control feedback,
similar to how DCCP defines CCIDs, and if so, document such
extensions as standards-track RFCs.<br>
* Define evaluation criteria for proposed mechanisms, and publish
these as an Informational RFCs.<br>
* Find or develop candidate congestion control algorithms, verify
that these can be tested on the Internet without significant risk,
and publish one or more of these as Experimental RFCs.<br>
* Publish the result of experimentation with these Experimental
algorithms on the Internet<br>
* Once an algorithm has been found or developed that meets the
evaluation criteria, and has a satisfactory amount of documented
experience on the Internet, publish this algorithm as a Standards
Track RFC. There may be more than one such algorithm.<br>
<br>
The work will be guided by the advice laid out in RFC 5405 (UDP
usage guidelines) and RFC 2914 (congestion control principles).<br>
<br>
The following topics are out of scope:<br>
* Circuit-breaker algorithms for stopping media flows when network
conditions render them useless; this work is done in AVTCORE.<br>
* Media flows for non-interactive purposes like stored video
playback; those are not as delay sensitive as interactive traffic.<br>
* Modifications to TCP of any kind.<br>
<br>
The working group is expected to work closely with the RAI area,
including the underlying technologies being worked on in the AVTCORE
and AVTEXT WGs, and the applications/protocol suites being developed
in the CLUE and RTCWEB working groups.<br>
It will also liaise closely with other Transport area groups working
on congestion control, and with the Internet Congestion Control
Research Group of the IRTF.<br>
<br>
Deliverables<br>
<br>
* Evaluation criteria for congestion control algorithms for
interactive real time media - Informational RFC<br>
* RTCP extensions for use with congestion control algorithms -
Standards-track RFC<br>
* Candidate congestion control algorithm for interactive real time
media - Experimental RFCs (likely more than one)<br>
* Experimentation and evaluation results for candidate congestion
control algorithms - Informational RFC<br>
* A recommended congestion control algorithm for interactive real
time media - Standards-track RFC <br>
<br>
Milestones<br>
<br>
NN NNNA: (chartering + 1 month) Publish first draft of evaluation
crieria<br>
NN NNNB: Adopt first congestion control candidate as WG draft<br>
NN NNNC: (A + 4 months) Submit evaluation criteria to IESG as
Informational<br>
NN NNND: (C + 1 month) Submit first congestion control candidate to
IESG for Experimental publicaiton<br>
NN NNNE: (D + 3 months) First draft of evaluation results<br>
NN NNNF: (=E) First draft of standars-track congestion control<br>
NN NNNG: (F + 6 months) Submit congestion control to IESG for
Proposed Standard<br>
(time from chartering to end of charter is 15 months)<br>
<br>
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