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On 11/01/2011 02:12 PM, Justin Uberti wrote:
<blockquote
cite="mid:CAOJ7v-2Ne+p_6R7rMUhe8vNYgTK5__FepG5UNsqJA_-iAiCk6Q@mail.gmail.com"
type="cite">Good point. Keep in mind that even within a single
source/SSRC, packets may be sent with different DiffServ markings
(consider speech vs silent audio, or different temporal layers for
video)<br>
</blockquote>
I get a headache just thinking about how to signal congestion
control for that .... especially since it's not improbable that the
Diffserv bits will be cleared by the time the packets get to the
recipient, so it might be impossible for the recipient to tell which
packets experienced what queues.<br>
<br>
Can we add a warning to our documents saying "don't do this if you
use this type of congestion control", or do you think the practice
is widespread enough that we have to deal with it?<br>
<br>
(if nobody's doing it, a warning might be enough to prevent anyone
from starting it.)<br>
<blockquote
cite="mid:CAOJ7v-2Ne+p_6R7rMUhe8vNYgTK5__FepG5UNsqJA_-iAiCk6Q@mail.gmail.com"
type="cite"><br>
<div class="gmail_quote">
On Tue, Nov 1, 2011 at 4:39 PM, Harald Alvestrand <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:harald@alvestrand.no">harald@alvestrand.no</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
I just remembered one reason why we put an SSRC list in the
REMB message, and I don't think we've mentioned this on the
list....<br>
<br>
If SSRCs get sent with different DiffServ codepoints, they are
going to experience very different congestion states at
intermediate routers. It doesn't make sense to give feedback
on them jointly or on average.<br>
<br>
We don't know yet how we should divide those SSRCs into
different groups, but it's good to have the ability to do so
without changing the signalling.<br>
<br>
The congestion state on a set of SSRCs should only be applied
as a basis for controlling traffic over the set of data that
is sent with the same DiffServ markings.<br>
(Grammar bad. I beg forgiveness, and hope the meaning
carries.)<br>
<br>
Harald<br>
<br>
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</blockquote>
</div>
<br>
</blockquote>
<br>
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