Re: [MMUSIC] RFC 5576 is da answah

[Christer Holmberg <[e-mail]>]

Hi,

>From Section 8:
>
>   When used with the SDP Offer/Answer Model [RFC3264], SDP source-
>   specific attributes describe only the sources that each party is
>   willing to send (whether it is sending RTP data or RTCP report
>   blocks).  No mechanism is provided by which an answer can accept or
>   reject individual sources within a media stream; if the set of
>   sources in a media stream is unacceptable, the answerer's only option
>   is to reject the media stream or the entire multimedia session.
>
> [BA] The advice above appears to only apply to an answerer that supports RFC 5576.  If it doesn't support RFC 5576, then it
> will presumably ignore the a=ssrc lines, but may not reject the media stream (by setting the port to zero) or the entire session.
> In this case, it may not be clear to the Offerer whether in fact it can send all the declared ssrc's or not.  Contrast this with the
> CLUE approach in which receiver gets to indicate what media captures it would like to receive.

In CLUE we have a requirement to be able to communicate with "non-CLUE" and "single stream" devices, so also there we may have to deal with the case where an endpoint doesn't support CLUE and/or RFC 5576.

Also keep in mind that, eventhough max-ssrc allows you to specify the number of streams, it is currently not a mechanism to indicate WHICH streams are accepted/rejected.

Regards,

Christer