Re: [Sip-implementors] offer-answer and backward compatibility

[Sanjay Sinha]

Christer Holmberg wrote:

[EMAIL PROTECTED]">

Hi,

RFC 3261 sec. 13.2.1 says that a UAC MUST treat the first session
description it receives in a reliable non-failure message as the answer,
and MUST ignore any session descriptions in subsequent responses to the
initial INVITE. Does it mean that if 183 has SDP in response to Invite's
offer, it should be treated as answer and SDP in 200 OK be ignored?

Yes, assuming that the 183 was sent reliably (using PRACK), AND that the 200 is received within the same dialog as the 183 (the INVITE may have been forked to multiple servers).

## Then, how about interoperability with a 2543 UAS that sends different SDPs in 18x & 200 OK? Or is changing SDP between the two responses not allowed even for a 2543 UAS?


Sanjay.

[EMAIL PROTECTED]">

Regards,

Christer Holmberg
Ericsson Finland

If yes, then how will it interoperate with a 2543 UAS that generates
different SDPs in 18x & 200 OK (because of say, CFNA)?

Thanks,
Sanjay.

_______________________________________________
Sip-implementors mailing list
[EMAIL PROTECTED]
http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors

_______________________________________________
Sip-implementors mailing list
[EMAIL PROTECTED]
http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors