It is not always the case. In case there are offer-answer exchanges with PRACK and UPDATE before 200 OK is sent, having SDP in 200 OK same as 183 is not a good idea. Though it seems logical to have the last offered/answered SDP in 200 OK, but there are lots of applications which do change SDP in 200 OK. It does violate offer/answer model though.
regards Rayees -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bala Neelakantan Sent: Wednesday, April 25, 2007 10:43 PM To: 'Siva M-Q16748'; 'Sarkar, Uttam'; [email protected] Subject: Re: [Sip-implementors] Early-media This violates the Offer/Answer model. See RFC 3264. The SDP in INVITE is the offer, and the SDP in 183 if present, it is early answer. So, if an answer is generated in 183, the same MUST be used in 200 OK too. Suppose the 200 OK choose to send different SDP, then it may be achieved by using different To Tag, and the caller will handle as faked forked call and accept the modified SDP in 200 OK. Thanks, Neel > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:sip-implementors- [EMAIL PROTECTED] On Behalf Of Siva > M-Q16748 > Sent: Friday, April 20, 2007 9:18 AM > To: Sarkar, Uttam; [email protected] > Subject: Re: [Sip-implementors] Early-media > > What would be the issue if they are not the same ?? > > > Siva M > -----Original Message----- > From: Sarkar, Uttam [mailto:[EMAIL PROTECTED] > Sent: Friday, April 20, 2007 7:49 PM > To: Siva M-Q16748; [email protected] > Subject: RE: [Sip-implementors] Early-media > > SDP in 183 and 200 must be same. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Siva > M-Q16748 > Sent: Friday, April 20, 2007 10:13 AM > To: [email protected] > Subject: [Sip-implementors] Early-media > > > Can the SDP of 183 and 200 OK be different > > I read somewhere that they should be the same > > If so , Is there any Logical reason why these two should be different ?? > > Siva M > > > Siva M > > _______________________________________________ > 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 _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ ---------------------------------------------------------------------------------- IMPORTANT The information contained in this e-mail any attachments is intended only for the named recipient and may be privileged or confidential. If you are not the intended recipient, please notify us immediately on +44 (0)1908 425000 and do not disclose, copy, distribute or take any action based on the contents of this e-mail. You should understand and accept that, when communicating with us by e-mail, it is not a totally secure communication medium. We accept no liability for any direct, indirect or consequential loss arising from any action taken in reliance on the information contained in this e-mail and give no warranty or representation as to its accuracy or reliability. DIGITALK has the facility to monitor and read both incoming and outgoing communications by e-mail. In line with industry efforts to reduce the proliferation of Un-Solicited SPAM messages, DIGITALK uses various methods including Reverse-DNS lookups and ban-lists to prevent malicious content reaching our users. This message and any attachments has been scanned for known viruses. However, we would advise you to ensure the content is indeed virus free. We do not, to the extent permitted by law, accept any liability (whether in contract, negligence or otherwise) for any virus infection and/or external compromise of security and/or breach of confidentiality in relation to transmissions sent by e-mail. VAT No: GB 876 3287 81. Reg No: 3080801 Place of Registration: England Registered Office Address: 2 Radian Court, Knowlhill, Milton Keynes ----------------------------------------------------------------------------------" _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
