From what port does an EP send RTP and RTCP packets? (Q32)

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It does not matter because H.323 does not specify this. Therefore, it would not be prudent for a receiving EP to give a packet's send port any significance. As evidence, H.225.0 and RFC1889 (RTP/RTCP) only talk about receive ports. Indeed, a "port" in these specs is inherently a receive port: A.3.4/H.225.0v3 and 3/RFC1889: "port: The 'abstraction that transport protocols use to distinguish among multiple destinations within a given host computer.'" A.3.6/H.225.0v3 and 3/RFC1889: "For each [RTP session] participant, the session is defined by a particular pair of destination transport addresses (one network address plus a port pair for RTP and RTCP)."