> -----Original Message-----
> From: Stefaan Willaert [mailto:[EMAIL PROTECTED]]
> Sent: Monday, May 14, 2001 4:03 AM
> To: [EMAIL PROTECTED]
> Subject: [Sip-implementors] use of session_id in SDP in 200
> OK response
>
>
>
> I've a question regarding the o-field in the SDP in
> the SIP 200 ok reponse message.
>
> In the SIP-draft ietf-sip-rfc2543bis-02 section B.1 the o-field in the
> response
> differs from the o-field in the SDP which was originally
> requested by the caller in the INVITE.
> What is the meaning behind this.
> It looks like we have finally one session with 2 different
> session-ids?
No. With unicast, there are effectively two sessions here, one from caller
to callee, and the other from callee to caller. Thus, there are two SDP and
two origin fields.
>
> According SDP a session is a set of multimedia senders and receivers
> and the data streams flowing from the senders to receivers.
> The o-field gives the originator of the session + a session id and
> session version number.
> If the callee responds to an invitation to a session shouldn't he
> reply with the same session-id in the SDP as the one which was
> passed in the request?
Nope. This is now explicit in bis-03:
>From B.3:
The answer to an offered SDP is based on the offered SDP. If the answer is
different in any way (different
IP addresses, ports, etc.), the origin line MUST be different in the answer,
since the answer is generated by
a different entity. In that case, the version number in the o line of the
answer is unrelated to the version
number in the o line of the offer.
-Jonathan R.
---
Jonathan D. Rosenberg, Ph.D. 72 Eagle Rock Ave.
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.jdrosen.net PHONE: (973) 952-5000
http://www.dynamicsoft.com
_______________________________________________
Sip-implementors mailing list
[EMAIL PROTECTED]
http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
