However, according to RFC3264: "The connection address and port in the answer indicate the address where the answerer wishes to receive media (in the case of RTP, RTCP will be received on the port which is one higher unless there is an explicit indication otherwise). This address and port MUST be present even for sendonly streams; in the case of RTP, the port one higher is still used to receive RTCP." Therefore, one can understand that it *implicitly* indicates that the port and address may not be present in case the media line is rejected completely. As the answerer does not wish to receive any RTP/RTCP media stream, there is no sense to include the address/port in the rejected media line.
Thanks, Erez -----Original Message----- From: Paul Kyzivat [mailto:[EMAIL PROTECTED] Sent: Tuesday, March 28, 2006 3:52 PM To: Erez Morabia Cc: [email protected] Subject: Re: [Sip-implementors] FW: Port zero in media line Erez Morabia wrote: > Hi, > RFC2543: If the callee wants to neither send nor receive a stream > offered by the caller, the callee sets the port number of that stream to > zero in its media description. > RFC2327: The connection (`c=') and attribute (`a=') information in the > session-level section applies to all the media of that session unless > overridden by connection information or an attribute of the same name in > the media description. > RFC2327: RTP profiles that specify the use of dynamic payload types must > define the set of valid encoding names and/or a means to register > encoding names if that profile is to be used with SDP. Have you looked at draft-ietf-mmusic-sdp-new-26? > Suppose I want to decline the audio stream I received in the offer, and > I'm not using the connection attribute in the session-level. > Please take a look on the following answer: > v=0 > > o=Me 1234567 1234567 IN IP4 1.2.3.4 > > s=My Session > > b=CT:384 > > t=0 0 > > m=audio 0 RTP/AVP 8 101 > > m=video 10004 RTP/AVP 34 > > c=IN IP4 1.2.3.4 > > a=rtpmap:34 H263/90000 > > > > > I have 2 questions here: > 1. Is it valid not to put the connection information in the declined > audio media section? It seems that you are *required* to have a c= either at session level, or else for each media description. So I think your usage above is not valid. If you are trying to minimize the size of your sdp you could simply move your existing c-line to session level. If you are looking to maximize clarity, you might want to put a "c=IN IP4 0.0.0.0" in the audio media description. > 2. Is it valid not to put rtpmap attribute for the dynamic payload (101) > in the declined audio media line? the requirement is only at SHOULD strength, so it is ok to leave it out. Paul > Thanks, > Erez > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
