IMG 1010 - Update Method
Overview
The UPDATE method allows a UAC to update parameters of a session, such as the SDP and session timers. The UPDATE has no impact on the state of a dialog. In that sense, it is like a re-INVITE, except that it can be sent before the initial INVITE has been completed. This makes it very useful for updating session parameters within early dialogs. The UPDATE method allows a greater control over a SIP session including, but not limited to, the following parameters:
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