Hello, All! We are using Kamailio as Webrtc to SIP proxy. Clinet's Chrome browser needs to have rtcp-mux option to work correct, so we are adding it in RTPENGINE->WS direction as: rtpengine_manage("trust-address replace-origin replace-session-connection *rtcp-mux-offer rtcp-mux-accept* ICE=force RTP/SAVPF"); Also we need to remove it in RTPENGINE->PSTN direction, we are trying to do it like this: rtpengine_manage("trust-address replace-origin replace-session-connection * rtcp-mux-demux* ICE=remove RTP/AVP"); But it does not work for us and a=rtcp-mux option in SDP goes to the SIP provider. Please help us to solve this! BR, Denys PS. Versions: Kamailio 4.4.5, rtpengine 5.2.1.0