[SIPForum-discussion] SIP UAS Behavior

[AMIT ANAND]

Hi Yip,

Yes if UAS supports timer and wants soem timer to run for this dialog. It
should tell UAC that it requires timer and also provide the session expire
value.
This is because UAS has to tell to UAC that it also supports timer, lets say
UAC has given request with refresher = uac and what if UAS does not support
timer?

So in response UAS has to include require=timer to say that it has also set
a timer for this call.

Cheers
Amit Anand


On Fri, Nov 5, 2010 at 9:48 AM, Yip, Sam SH <syip at pccwglobal.com> wrote:

>  Hello,
>
>
>
> I have an argument for session timer.
>
>
>
> The scenario is UAC requests session timer in the Invite message and
> indicate the refresher is UAC. Must UAS includes the Require header with
> value “timer” in the 2xx response?
>
>
>
> I read the RFC 4028. UAS must provide Require header. However, someone told
> me the part in section 9 is additional explanation for case 4 in table 2. So
> if the case is 5, Require header is optional.
>
>
>
>         UAC supports?  refresher parameter  refresher parameter
>
>                            in request           in response
>
>        -------------------------------------------------------
>
>              N                none                 uas
>
>              N                uac                  NA
>
>              N                uas                  NA
>
>              Y                none             uas or uac
>
>              Y                uac                  uac
>
>              Y                uas                  uas
>
>
>
>                         Table 2:  UAS Behavior
>
>
>
>    The fourth row of Table 2 describes a case where both the UAC and UAS
>
>    support the session timer extension, and where the UAC did not select
>
>    who will perform refreshes.  This allows the UAS to decide whether it
>
>    or the UAC will perform the refreshes.  However, as the table
>
>    indicates, the UAS cannot override the UAC's choice of refresher, if
>
>    it made one.
>
> *   If the refresher parameter in the Session-Expires header field in the*
>
> *   2xx response has a value of 'uac', the UAS MUST place a Require*
>
> *   header field into the response with the value 'timer'*.
>
>
>
> Many thanks.
>
> Sam
>
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-- 
Thanks
Amit Anand
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