[SIPForum-discussion] How to make Re-Invite without SDP

[mtrank at apexvoice.com]

An "INVITE without an SDP" is not the same as a "Re-INVITE".

Calls can be establshed when a user agent sends an empty INVITE message. The "offer" is then sent in the 200 OK response by the UAS and the UAC then sends the "answer" in the ACK message.

An empty INVITE is some times referred to as an "offer request", and this is described in the offer/answer RFC. I forget the number but the one right after 3261.

As for Re-INVITE's which do not change the media streams, these are useful as keep-alives and there is an RFC that describes this. Do google on "sip session timers" and "Supported:  timer".



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-----Original Message-----
From: Anthony Orlando <avorlando at yahoo.com>

Date: Sat, 3 Jan 2009 04:49:08 
To: <raghul82 at yahoo.co.uk>; nitin kapoor<nitinkapoorr at gmail.com>
Cc: <discussion at sipforum.org>
Subject: Re: [SIPForum-discussion] How to make Re-Invite without SDP


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