RtpEngine offers different ports with rtcp-mux

[Rahul]

Hi Richard,

I see an issue where the RtpEngine does not follow client's rtcp-mux preference by default. i.e to keep same ports for rtp and rtcp using rtcp-mux. Rtpengine responds with a different ports for an 'offer'. 

Rtpengine version is 13.5.1.16+0~mr13.5.1.16.

I am attaching the rtpengine logs here. I was thinking this might be an issue in RtpEngine ? Your thoughts are appreciated.

Regards,

Rahul

[Richard Fuchs]

That's expected and is compliant with the RFC. The separate RTCP port is provided as a fallback, in case the remote rejects (i.e. doesn't support) RTCP multiplexing.

In environments where you know that RTCP multiplexing is supported for sure or even mandatory (e.g. WebRTC), you can use `rtcp-mux=require` to omit the fallback RTCP port.

Cheers