RTCP port mayn't be next higher port in cases where your endpoint is behind NAT (router) and you need to do STUN query to find the mapped ip:port for the RTP media and RTCP channel. Your router mayn't always open two consecutive ports for RTP and RTCP.
In those cases, sending RTCP port attribute becomes mandatory to tell other end that RTCP port is not the next subsequent port but the one defined in the rtcp attribute. Thanks, Gaurav From: Manu Gowdru [mailto:manug...@gmail.com] Sent: Thursday, November 07, 2013 2:58 PM To: Gaurav Kumar Cc: Sip-implementors@lists.cs.columbia.edu Subject: Re: [Sip-implementors] RTCP port in remote SDP Hi Gaurav, When RTCP port is the next higher odd port number why is it mentioned in SDP?any reasons? Thanks, Manu On Thu, Nov 7, 2013 at 2:09 PM, Gaurav Kumar <gaurav.ku...@ittiam.com<mailto:gaurav.ku...@ittiam.com>> wrote: Hi Manu, Remote SDP can contain rtcp attribute in the SDP which can specified for each media (m = ) line. This rtcp attribute will tell us the rtcp port opened by the remote end. Thanks, Gaurav -----Original Message----- From: Manu Gowdru [mailto:manug...@gmail.com<mailto:manug...@gmail.com>] Sent: Thursday, November 07, 2013 11:51 AM To: Sip-implementors@lists.cs.columbia.edu<mailto:Sip-implementors@lists.cs.columbia.edu> Subject: [Sip-implementors] RTCP port in remote SDP Hi Guys, does remote sdp contains rtcp port. -- Manu _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu<mailto:Sip-implementors@lists.cs.columbia.edu> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors This is confidential Ittiam property. -- Keep Smiling :) Manu This is confidential Ittiam property. _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
