Agree with Attila. So in the given circumstance the UAS could have responded to the invite with a 488 to indicate that it didn't support the offered media.
Another possibility is for the UAS to return an answer where the port in the m-line is zero, thus rejecting the media stream since it can't handle any of the offered media. It could also include in that m-line the codecs it *does* support as an indication, though they will not be used at that time. Then the UAS could initiate another offer with the codecs it does support, in hopes of getting a working call. Whether that is better than the 488 is arguable. Probably not in most cases. Thanks, Paul Attila Sipos wrote: > 415 is often confused with 488. > > "415 Unsupported Media Type" is what you would use if if didn't understand > the SIP message body content. > > 488 (which is similar to 606) would be a more suitable response: > > 21.4.26 488 Not Acceptable Here > > The response has the same meaning as 606 (Not Acceptable), but only > applies to the specific resource addressed by the Request-URI and the > request may succeed elsewhere. > > and 606 is described as... > > The user's agent was contacted successfully but some aspects of the > session description such as the requested media, bandwidth, or > addressing style were not acceptable. > > A 606 (Not Acceptable) response means that the user wishes to > communicate, but cannot adequately support the session described. > The 606 (Not Acceptable) response MAY contain a list of reasons in a > Warning header field describing why the session described cannot be > supported. Warning reason codes are listed in Section 20.43. > > > Regards, > Attila > > > -----Original Message----- > From: sip-implementors-boun...@lists.cs.columbia.edu > [mailto:sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of Peter > Nijhuis > Sent: 27 April 2009 14:30 > To: Shanbhag, Somesh (NSN - IN/Bangalore); ext friend friend; sip fourm > Subject: Re: [Sip-implementors] Query for SDP Negotiation > > I think Callee should respond with 415 unsupported media type, since it is > not supporting media types 102, 0, 8 or 106. > > Met vriendelijke groet, with kind regards, mit freundlichen Gruß > > Peter Nijhuis > > > >> -----Original Message----- >> From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip- >> implementors-boun...@lists.cs.columbia.edu] On Behalf Of Shanbhag, >> Somesh (NSN - IN/Bangalore) >> Sent: maandag 27 april 2009 15:07 >> To: ext friend friend; sip fourm >> Subject: Re: [Sip-implementors] Query for SDP Negotiation >> >> The basic thing is CALLEE has to take the subset of codecs offered by >> CALLER and reply back. >> But in your case, CALLEE is replying with different set of codecs (97 >> 101) in reply to CALLER codecs ( 102 0 8 106 ) IMHO, since the >> capabilities mis-match, immdiately end the call using BYE / CANCEL >> which ever is relevant. >> >> >> Somesh >> >> -----Original Message----- >> From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip- >> implementors-boun...@lists.cs.columbia.edu] On Behalf Of ext friend >> friend >> Sent: Monday, April 27, 2009 2:59 PM >> To: sip fourm >> Subject: [Sip-implementors] Query for SDP Negotiation >> >> Dear Folks, >> I have doubt in the following scenario. >> >> Caller's sdp : >> >> v=0 >> o=- 1234 1 IN IP4 10.10.20.35 >> s=- >> c=IN IP4 10.10.20.35 >> t=0 0 >> m=audio 12000 RTP/AVP 102 0 8 106 >> a=rtpmap:102 iLBC/8000 >> a=rtpmap:0 PCMU/8000 >> a=rtpmap:8 PCMA/8000 >> a=rtpmap:106 telephone-event/8000 >> >> >> Callee's negotiated sdp : >> >> v=0 >> o=- 3449811996 3449811996 IN IP4 10.10.20.4 s=SJphone c=IN IP4 >> 10.10.20.4 t=0 0 m=audio 49164 RTP/AVP 97 101 c=IN IP4 10.10.20.4 >> a=rtpmap:97 iLBC/8000 >> a=rtpmap:101 telephone-event/8000 >> a=fmtp:101 0-16 >> a=setup:active >> a=sendrecv >> >> In this case,Is callee's negotiation method is wrong? >> >> Callee should send like m=audio 49164 RTP/AVP 102 106 rite? >> >> In this case, after call establishment, >> from caller sending RTP using 102 (UnKnown) >> from callee sending RTP using 97 (iLBC) >> >> So caller hearing callee's audio but callee not able to hear caller's >> audio. >> >> please clarify this issue. >> >> Thanks & Regards, >> vijay >> >> >> Bring your gang together. Do your thing. 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