The reinvite for session refresh is no different than any other reinvite. There is really no way for the recipient to determine whether this reinvite was prompted by the need to refresh the session or for some other reason.
From the recipients point of view this is just a reinvite that must be responded to. One of the things that any reinvite does is start/end/refresh a session timer.
From the refresher's point of view, every time it sends a reinvite, that reinvite must be considered a refresh, and so revise the timer value. That is true regardless of why the reinvite is being sent. The only thing special is that the refresher needs to run a timer, and if it goes off, send a reinvite even though one was not otherwise needed. Since in that case one was not otherwise needed, it is reasonable to assume that the offer it contains will be unchanged. But that need not be the case - the opportunity could be taken to change something, or the reinvite could be sent without an offer, making the reinvitee respond with an offer.
Paul
Pang Xiaogang-r63373 wrote:
Hi Ramesh
1. Should the re-invite for Session timer have a sdp body?
[David] The re-invite always contains the same offer sdp body as it uses currently. And also the 200 response to the re-invite should contains the same answer sdp.
2. how can we say that the invite that we received is for session timer or a modification of the SDP? I just want to avoid processing the SDP body if the reinvite is only for Session Timer.
[David] The only difference of a refresh request or modification request is the SDP. If the SDP messages is different from the previous one, it is not only refreshes the session, but also means it is a modification request.
3. Can a ReInvite act both as a session timer and modification to RTP?
[David] Yes.
Regards,
David
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ramesh Ramamurthy Sent: Tuesday, January 25, 2005 7:13 AM To: [email protected] Subject: [Sip-implementors] Session Timer questions.
Hi all,
1. Should the re-invite for Session timer have a sdp body?
2. how can we say that the invite that we received is for session timer or a modification of the SDP? I just want to avoid processing the SDP body if the reinvite is only for Session Timer.
3. Can a ReInvite act both as a session timer and modification to RTP?
Thanks Ramesh _______________________________________________ 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
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