Re: [rtcweb] Signalling, SDP, and the way we think about interconnecting RTCWEB applications

Wolfgang <wolfgang.beck01@googlemail.com> Sat, 15 October 2011 09:59 UTC

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Date: Sat, 15 Oct 2011 11:59:46 +0200
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From: Wolfgang <wolfgang.beck01@googlemail.com>
To: "<rtcweb@ietf.org>" <rtcweb@ietf.org>
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Subject: Re: [rtcweb] Signalling, SDP, and the way we think about interconnecting RTCWEB applications
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First, the draft is not about SIP vs XMPP vs xy. All those protocols
try to be general and necessarily suffer from feature creep and
complexity. SIP once started as a much simpler alternative to H.323
and look where we are now. XMPP has defined more than 300 extensions.
But I think there is not much disagreement about the call signaling
part.

The question is if we can get rid of SDP as well. If both sides
*implicitly* know what codec parameters they are going to use there is
no longer the need to negotiate them. If caller and callee use the
same RTCWEB client this should be doable. The RTCWEB server may need
some hints about the browsers capabilities -- eg does it support a
camera, is the bandwidth limited -- to provide it with an applicable
RTCWEB client. But we don't need a way to convey and negotiate dozens
of codec parameters.

If we insist on interoperability between RTCWEB client A and RTCWEB
client B we will end up re-inventing SDP and/or SIP.  And of course we
will have to keep RTCWEB and SDP standardization in sync.


Wolfgang