Re: [AVT] Additional requirement in Congestion control for the "draft-kristensen-avt-rtp-h264-rcdo-00"

On 24/07/07, steve.norreys@bt.com <steve.norreys@bt.com> wrote:
> Hi
>
> I just skimmed the draft-kristensen-avt-rtp-h264-rcdo-00
> draft and section 6 that deals with congestion control puzzled me somewhat.
> The reference to the main congestion control in RFC3550 in the first
> sentence is fine but I don't understand the relationship to the rest of the
> paragraph. As the media in a sip sense has been 'offered and answered'
> therefore congestion techniques will not apply to this 'session' as
> congestion control traditionally only applies to the setup of new
> 'sessions'.

The text in section 6 is stolen from the draft "How to Write an RTP
Payload Format" (draft-ietf-avt-rtp-howto-01) - where the text is
proposed as an initial text for this section in the template provided.
However, an RTP payload format specification is not written solely for
SIP applications - so other scenarios apply as well.

> The packet loss could be as a result of congestion and could be used as a
> indicator to apply congestion control at this entity that is suffering the
> packet loss but this is not the only indication of congestion. Presumably
> one of the entities monitoring the packet loss is the UE which I hope is not
> under congestion but could still be suffering from packet loss does it then
> report this loss to the entity sending the higher resolution video. I think
> that some clarification of what the additional requirement to monitor packet
> loss is needed.

Thanks for the input, it's possible to expand and elaborate the text
in the H264-RCDO RTP payload format draft.

-- Tom

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