Re: [MMUSIC] Not fixing a=rtcp and rtcp-mux exclusive

[Christer Holmberg <[e-mail]>]

Hi,

Commenting on my own comment.

>> We can for sure define a new attribute, if people prefer that.
>>
>> But, it still wouldn't solve Paul's issue, that a non-ICE endpoint that doesn't support the attribute may start sending RTCP on RTP+1. But, at least the offerer would see from the answer that the answerer does not support mux-exclusive, and can take proper actions.
>>
>> We can define new attribute that specifies address and port for both RTP and RTCP similar to ICE candidate or a=rtcp attribute and set address in c= line to IN IP4 0.0.0.0. This way any end point that does not understand this attribute will send no media.
>
> Another option would be to set the m- line port to zero, like we do for bundle-only. Then, if the answerer doesn't support the attribute, it won't use the m- line.
>
> Example:
>
> c=IN IP4 11.22.33.44
> m=0 RTP/AVP 0 99
> a=mux-exclusive: 12345  <------- 12345 is the port to be used for RTP and RTCP

One problem with this solution is that an intermediary that doesn't support the attribute won't know where to forward the media, it the m- line port value is 0. It very likely will assume there will be no media to begin with.

Regards,

Christer