Re: [AVTCORE] Draft new: draft-holmberg-avtcore-5761-update-00

[Paul Kyzivat <[e-mail]>]

On 6/22/16 5:22 PM, Roni Even wrote:

> */That is tied to my question about can the answerer use a=RTCP to
> receive multiplex RTP and RTCP without explicitly using rtcp-mux
> attribute?/*

I agree that is fuzzy. IMO, attempts to do that ought to be considered 
an error. But I don't know what sort of recovery action should be taken 
for this error.

Note that for an *answerer* to attempt this leads to nonsense. It means 
the offerer will be sending both RTP and RTCP to a single port while the 
answerer (who set this up) must still send them to separate ports. And 
since it wasn't anticipating that these be multiplexed it will 
presumably be buffering as if they are going to separate ports. I would 
think that would make a mess.

It would be less problematic if first signaled by the offerer, because 
then the answerer knows what is going on if it also uses a single for 
both in the answer. But in this case they ought to be explicitly 
signaling that they are multiplexing.

It would be good to revise the definition of a=rtcp to clarify this, so 
somebody not aware of a=rtcp-mux doesn't do this by accident.

	Thanks,
	Paul