Re: [MMUSIC] ICE and RTCP host components

Paul Kyzivat <pkyzivat@alum.mit.edu> Tue, 20 October 2015 16:18 UTC

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From: Paul Kyzivat <pkyzivat@alum.mit.edu>
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Date: Tue, 20 Oct 2015 12:18:28 -0400
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Subject: Re: [MMUSIC] ICE and RTCP host components
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On 10/20/15 8:28 AM, Christer Holmberg wrote:
> Hi,
>
> ICEbis and ice-sip-sdp say that, when a separate port is used for RTCP,
> separate components are allocated for RTP and RTCP.
>
> Assume the offerer uses a=rtcp to specify a port for RTCP, but the
> answerer doesn’t support the attribute (and instead will use RTP port+1
> for RTCP): Does that mean that the offerer needs to allocate RTCP host
> components both for the a=rtcp value and RTP port+1?

This has always been non-sensical to me. The reason to use a=rtcp is 
because you *can't* use the +1 rule. I don't see how this could ever 
work when the answerer doesn't support it. But neither do I have an idea 
how it could have been fixed.

(A better answer would have been to have rtcp-mux be the default, with 
an option to put it on a separate port. But this would have had to be 
defined when RTP was first specified.)

	Thanks,
	Paul

> Section 5.1.3.1. of ICEbis talks about the rtcp-mux, when it is now
> known whether the answerer will support it, but this is about having two
> different ports for RTCP.
>
> Regards,
>
> Christer
>
>
>
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