Re: [Sipping] Liaison Statement on offer/answer procedures

[Paul Kyzivat <pkyzivat at cisco.com>]

Anders Kristensen wrote:
> 
> Christer Holmberg wrote:
>>> - If an UPDATE (inside or outside of a reINVITE) fails, any o/a in 
>>> the UPDATE has no effect on the media session state.
>>> [Ian Elz ] OK, but how will we determine if an UPDATE is inside or 
>>> outside a re-INVITE? 
>>  
>> [Christer] I assume that any stateful entity must know whether it has 
>> a pending re-INVITE transaction for a specific call or not.
> 
> That's not actually enough. A UAS (or dialog stateful proxy) cannot know 
> whether an UPDATE received shortly after a 2xx is sent upstream was sent 
> before or after the 2xx was received by the UAC. We could add an 
> explicit indication to that effect, I suppose...

Yes. Taking this approach to the current problem requires that we find a 
solution to knowing whether the update was sent inside the reinvite or not.

	Paul
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