HP-UX C SIP Stack Programmer's Guide (Novembery 2007)

382 HP-UX C SIP Stack Programmer’s Guide

SIP Session Timer

When the callback is called with the

RVSIP_CALLLEG_SESSION_TIMER_DEST_NOT_SUPPORTED reason, it

notifies the local party that a 2xx final response was received, but the server

does not support the Session Timer. The application should return

synchronously whether or not it wants to execute Session Timer.

The Session Timer mechanism can be operated as long as one of the two UAs in

the call leg supports the extension. If the application decides to operate the

Session Timer, that side will send the refresh. The other side will see the

refreshes as repetitive re-INVITEs. The default behavior is to execute the

Session Timer mechanism for the call.

When the callback is called with the

RVSIP_CALLLEG_SESSION_TIMER_APP_REFRESH_REQUEST_REJEC

T reason, it notifies the application that the refresher preference did not match

the call refresher. The application should return synchronously whether or not it

wants to execute the Session Timer. If the application decides to operate the

Session Timer mechanism, the refresher will be different from the application

request. The default behavior is to execute the Session Timer mechanism for the

call.

AMPLE CODE The sample code below demonstrates an implantation of the

CallLegSessionTimerRefreshAlertEv() callback. This callback notifies that the

alert time (the time in which the application needs to send re-INVITE or

UPDATE to refresh the call) is expired.