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

378 HP-UX C SIP Stack Programmer’s Guide
SIP Session Timer
Preference and Negotiation Parameters
The preference and negotiation parameters are temporary parameters used
before the final session timers parameters were determined. The preference
parameters are the parameters that the local party prefers for this session. You
can only set the preference parameters. Each setting of preference parameters is
valid for a single session timer refresh within a dialog (either an initial or
subsequent refresh). The negotiation parameters are the parameters that are
negotiated with the remote party. You can only get the negotiation parameters.
Before a UA sends a refresh request or response to a refresh request, the UA can
set the preference parameters using the
RvSipCallLegSessionTimerSetPreferenceParams() function. Upon receiving a
refresh request or a 2xx response to a refresh request, the UA can learn about the
remote party requested parameters using the
RvSipCallLegSessionTimerGetNegotiationParams() function.
Session Expires, Min-SE, Refresher Type
The final session timer parameters that were determined in the last negotiation
process.
Alert Time
The time in which the refresh request will be sent. For more information, see
Timers.
API FUNCTIONS The SIP Stack provides the API functions listed below to support the Session
Timer mechanism.
GET AND SET FUNCTIONS
The following Get and Set functions are provided for session timer support:
RvSipCallLegSessionTimerSetPreferenceParams()
Sets the preferred Session Timer parameters associated with this call. These
parameters may not be equal to the Session Timer parameters of the call in the
end of the negotiation. The preference parameters setting is valid for a single
session refresh request or response. If an UNDEFINED value is set as the
minSE, it is configured as the default (90 seconds) according to the Session
Timer RFC and the Min-SE header will not appear in the upcoming sent
messages.