Yes if UAC is assuming itself as the refresher then it should also tune the 
timer value for session refresh in order to glare conditions. It can be 
starting the timer to half of the value as present in session expires header.

rgds
Anuradha

________________________________________
From: [EMAIL PROTECTED] [EMAIL PROTECTED] On Behalf Of Paul Kyzivat [EMAIL 
PROTECTED]
Sent: Thursday, October 09, 2008 7:32 PM
To: Rockson Li (zhengyli)
Cc: Govardhana Sankanna Nagendraprasad; [email protected]
Subject: Re: [Sip-implementors] UAC's behavior upon receiving   200OK   
forINVITEwithout Refresher

IMO you can do as you wish. But to maximize interop you probably don't
want to reject the call.

The assumption was that the UAC supported but didn't require session
timer. So just accepting the call and *not* acting as refresher will
suit its needs. But if there is a proxy in the middle that is expecting
a refresh, and the UAS *isn't* going to do it, then that may cause some
difficulty.

If the UAC decides to act as a refresher, things will still work out
even if the UAS also decides to act as refresher. If they both decide to
refresh at exactly the same time then you might get glare, but there are
recovery procedures for that. To minimize the chance of that, the UAC
could adjust the time it plans to do the refresh a little bit, to skew
it from what the UAS is likely to try.

        Thanks,
        Paul

Rockson Li (zhengyli) wrote:
> Shane,
>
> I think not to end the call might be fine.
> But to act as if "refresher=uac" is received might be troublesome,
> Since UAC does not know if UAS decides to refresh itself,
> in that case, you would end up with glare re-INVITE when both sides
> intend to refresh later.
>
> I think it would be better to assume "refresher=uas" being received.
>
> Regards,
> -Rockson
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of
> Shane Lee
> Sent: Thursday, October 09, 2008 7:38 PM
> To: Suganya D
> Cc: Govardhana Sankanna Nagendraprasad;
> [email protected]
> Subject: Re: [Sip-implementors] UAC's behavior upon receiving 200 OK
> forINVITEwithout Refresher
>
> Hi,
>
> For better interoperability, I don't think it is a good idea to reject
> the call. I agree with Anuradha, the caller had better continue the call
> and act as if "refresher=uac" is received.
>
> Best Regards
> Shane
> _______________________________________________
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