Re: [rtcweb] RTP Usage: Is RTP Retransmission REQUIRED or RECOMMENDED

"Olle E. Johansson" <oej@edvina.net> Thu, 05 July 2012 16:07 UTC

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From: "Olle E. Johansson" <oej@edvina.net>
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To: Martin Thomson <martin.thomson@gmail.com>
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Subject: Re: [rtcweb] RTP Usage: Is RTP Retransmission REQUIRED or RECOMMENDED
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5 jul 2012 kl. 17:48 skrev Martin Thomson:

> On 4 July 2012 12:39, Roman Shpount <roman@telurix.com> wrote:
>> Unless we have a SIP end point that supports DTLS-SRTP  and ICE, understands
>> AVPF profile, and knows how to negotiate RTP retransmissions and other RTP
>> extensions, [...]
> 
> I think that this is a little pessimistic.  SRTP with SDES is still a
> viable option, for this reason.  The SIP endpoint can implement
> ICE-lite and still interoperate.  AVPF senders can interoperate with
> AVP receivers unless you have some strange business going on at the
> AVP end.  And RTP retransmission is easy to claim support for without
> actually supporting (either the NACKs or the retransmissions got lost,
> I don't know which, sorry).


The discussion started with REQUIREments on developers. 

"The development
   of the WebRTC framework provides an opportunity for us to review the
   available RTP features and extensions, and to define a common
   baseline feature set for all WebRTC implementations of RTP.  This
   builds on the past 15 years development of RTP to mandate the use of
   extensions that have shown widespread utility, while still remaining
   compatible with the wide installed base of RTP implementations where
   possible."

http://www.ietf.org/id/draft-ietf-rtcweb-rtp-usage-03.txt

I really think we should be very careful to REQUIRE implementations to implement
functions that break this goal.

/O