Hi Alan,
Thanks for the clarifications and the pointer to the
service-examples draft. Regarding the case 3, I had
a couple of more questions...
>3. Different offer, but same answer
> --------------------------------
>SID>> In case the caller wants to put our client on hold,
>SID>> and we do not put the caller on hold in turn, then the
>SID>> answer involves no change to the session data. In such a
>SID>> case is it necessary for the server to increment version?
The section 2.1 of the draft-ietf-sipping-service-examples-02.txt
is exactly the case mentioned above. The user B sends
a re-INVITE to A who responds with the same SDP that
had been sent in step F1 (in both the steps: F12 and F18).
So A need not increment version of the o= line if the
answer has not changed... Is this understanding correct?
If so, would it be right to say that the UAC cannot
determine whether the SDP that was recd from a peer
is an answer to the latest or a previous offer looking
at the answer SDP alone? Isn't this feature desirable
from the negotiation procedure?
Cheers,
Siddharth.
---------------------
Siddharth Toshniwal @ Hughes Software Systems,
http://www.hssworld.com
Alan Johnston <[EMAIL PROTECTED]> on 09/05/2002 01:44:32 AM
To: Siddharth J Toshniwal/HSSBLR, Senthil K Kumar <[EMAIL PROTECTED]>
cc: [EMAIL PROTECTED]
Subject: RE: [Sip-implementors] Clarifications regarding SDP "o=" line
Sidharth,
You have found an error in the basic call flows document that I will
fix. In Message F10 of flow 3.7, A does change the port, so the version
number in the SDP should be incremented. I will make this change to the
document. Any time the SDP has changed, the version number should be
changed as well.
Also, for questions about SDP and call hold, take a look at the Service
Examples draft
(
http://www.ietf.org/internet-drafts/draft-ietf-sipping-service-examples-02.
txt)
since it shows (hopefully) the correct behavior in a few flows.
Thanks,
Alan Johnston
sip:[EMAIL PROTECTED]
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