To reject an offered stream, the port number in the corresponding stream in the answer MUST be set to zero. Any media formats listed are ignored. At least one MUST be present, as specified by SDP.
Hi Somesh, This is what I understood from RFC. By putting port = 0 will reject the stream. And there must be at least a Codec present per m line. As u are rejecting these codecs, the list won't contain any Codec that UA2 may support. Now UA2 should copy the Codecs from the original offer(from UA1),that will tell which codecs are been rejected. Moreover If the Dialog wish to add more Codecs Later, the rejected m-line slot could be reused. Regards, Jayesh A Sangpal DLink India Ltd. Bangalore > Hi All, > > I have the following doubt in SDP. > > UA1 ========================> UA2 > Invite(SDP) ------------------> > > >From UA1: > SDP has both audio & video capabilities. > > At UA2: > UA2 doesn't have audio capability & so it doesn't > know any codec. But according to RFC 3264, it MUST > reply something for audio. We have two choices - > > 1) Reply with port = 0 > --> But we don't know the codecs? > > 2) Reply with inactive > --> But we don't know the codecs? > > Is it feasible to use either of the approach? > Please correct me if I am wrong? > is it valid to construct m= lines in SDP without > any codec? > > With regards > Somesh S. Shanbhag > _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
