RE: [Sip-implementors] Offer-answer queries

[nataraju.alilaghatta]

Title: Message

Regards, Nataraju A.B. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Prabha Sent: Friday, December 12, 2003 6:41 PM To: Ranjit Avasarala (WT01 - TELECOM & INTER-NETWORKING SOLUTIONS); [EMAIL PROTECTED] Subject: Re: [Sip-implementors] Offer-answer queries   Hi Ranjit,  Thanks for the response. But i am still not clear. Here  200 Ok has been sent with codecs 3 and 5. It means to say that he is supporting both 3 and 5. Now how does an offeror identify the final negotiated codec without seeing the payload type in RTP header.   If 200 OK would have come with one coder, then it is clear fto the offeror regarding the accepted codec details.   [ABN] the result of the offer/answer negotiation is not the content of the data carried in the message but the agreed upon set of encodings supported by both the parties…   If both the parties support codec 3 & 5 obviously the RTP payload could be one of the two offers carried in the initial offer…     Please can you give some more inputs on this.   Thanks,  Prabha N ----- Original Message ----- From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] ; [EMAIL PROTECTED] Sent: Friday, December 12, 2003 5:15 PM Subject: RE: [Sip-implementors] Offer-answer queries   Hi      The accepted codec gets reflectd in 200 OK. so there is no need to send negotiated codecs in ACK. If no offer is sent in INVITE by caller, then the callee send his offer in 200 OK and the negotiated codec should be sent by caller in ACK     Thanks & Regards Ranjit Wipro Technologies E-City, Bangalore Ph: 8520408/16 extn: 2173   -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Prabha Sent: Friday, December 12, 2003 4:42 PM To: [EMAIL PROTECTED] Cc: Jonathan Rosenberg Subject: [Sip-implementors] Offer-answer queries Hello,   I have a question regarding the SDP part of the Invite request.    suppose user agent  "A" wants to talk to user agent "B", he sends a INVITE  request to B.  the SDP part of the invite request is as follows,      v= 0  o= A 1464112736 1464112736 IN IP4 151.209.33.190  s=Calling  c=IN IP4 pgs-477  t=0 0  m=audio 2074 RTP/AVP 0 3 5  a=rtpmap:0 PCMU/8000  a=rtpmap:3 GSM/4000  a=rtpmap:5 ADPCM/4000    If user agent accepts the request and agrees to talk to user agent A, he  sends a OK response with SDP as followed.    v= 0  o= B1464112736 1464112736 IN IP4 151.209.33.194  s=Answering the call  c=IN IP4 pgs-451  t=0 0  m=audio 2074 RTP/AVP  3 5  a=rtpmap:3 GSM/4000  a=rtpmap:5 ADPCM/4000    now why can’t the user agent A send an ACK by selecting one of the coders specified in answer AS mentioned below ?   v= 0  o= A 1464112736 1464112736 IN IP4 151.209.33.190  s=Calling  c=IN IP4 pgs-477  t=0 0  m=audio 2074 RTP/AVP  3 a=rtpmap:3 GSM/4000   than analyzing the payload type (PT) header field in the RTP Packet.   Thanks in advance Prabha N Confidentiality Notice     The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain confidential or privileged information. If you are not the intended recipient, please notify the sender at Wipro or [EMAIL PROTECTED] immediately and destroy all copies of this message and any attachments. _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors Confidentiality Notice The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain confidential or privileged information. If you are not the intended recipient, please notify the sender at Wipro or [EMAIL PROTECTED] immediately and destroy all copies of this message and any attachments.

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