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Re: [AVT] I-D ACTION:draft-ietf-avt-rtp-and-rtcp-mux-06.txt
Internet-Drafts at ietf.org writes:
>Title : Multiplexing RTP Data and Control Packets on a Single Port
>Filename : draft-ietf-avt-rtp-and-rtcp-mux-06.txt
> Note: since all RTCP packets MUST be sent as compound packets
> beginning with an SR or an RR packet ([1] Section 6.1), one might
> wonder why RTP payload types other than 72 and 73 are prohibited
> when multiplexing RTP and RTCP. This is done to ensure robustness
> against broken nodes which send non-compliant RTCP packets, which
> might otherwise be confused with multiplexed RTP packets.
This should mention that relaxing that restriction is under consideration,
(I forget the exact draft name) and that by including the PT restrictions
in this draft we avoid a potential conflict with the other draft (i.e. it
may not be only "broken nodes"). I also would remove the word "broken",
it's misleading. They are non-compliant with 3261 (until that draft is
approved).
> When the Session Description Protocol (SDP) [8] is used to negotiate
> RTP sessions following the offer/answer model [9], the "a=rtcp-mux"
> attribute (see Section 8) indicates the desire to multiplex RTP and
> RTCP onto a single port.
We should also discuss interaction with offering both "a=rtcp-mux" and
"a=rtcp <port>". I can see an endpoint wanting (or needing) to include
both. The answer selects between rtcp-mux and "normal" rtcp handling
(including a=rtcp, though there's no direct way to know if the answerer
supports it).
--
Randell Jesup, Worldgate (developers of the Ojo videophone), ex-Amiga OS team
rjesup at wgate.com
"The fetters imposed on liberty at home have ever been forged out of the weapons
provided for defence against real, pretended, or imaginary dangers from abroad."
- James Madison, 4th US president (1751-1836)
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