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

244 HP-UX C SIP Stack Programmer’s Guide

Subscription State Machine

This event notifies both subscriber and notifier applications about the

termination of the notification.

RvSipSubsFinalDestResolvedEv()

Notifies the application that the subscription is about to send a message after the

destination address was resolved.

SUBSCRIPTION

TATE MACHINE

The Subscription state machine represents the state of the subscription

establishment between two SIP User Agents. The RvSipSubsStateChangedEv()

callback reports subscription state changes and state change reasons. The state

change reason indicates how the subscription reached the new state.

The subscription associates with the following states:

RVSIP_SUBS_STATE_IDLE

The IDLE state is the initial state of the Subscription state machine. Upon

subscription creation, the subscription assumes the IDLE state. It remains in this

state until RvSipSubsSubscribe() is called, whereupon it should move to the

SUBS_SENT state.

RVSIP_SUBS_STATE_SUBS_SENT

After calling RvSipSubsSubscribe() and sending a SUBSCRIBE request, the

subscription enters the SUBS_SENT state. The subscription remains in this

state until it receives a final response from the notifier. If a 2xx class response is

received, the subscription assumes the SUBS_2XX_RCVD state. If a 3xx class

response is received, the subscription moves to the REDIRECTED state. If the

subscription is rejected with a 401 or 407 response, the subscription moves to

the UNAUTHENTICATED state. For all other response codes, subscription

assumes the TERMINATED state.

If a NOTIFY request is received before a 2xx response is received, the

subscription assumes the NOTIFY_BEFORE_2XX_RCVD state.

RVSIP_SUBS_STATE_REDIRECTED

A subscription in the SUBS_SENT state may receive a 3xx class response. In

this case, the subscription assumes the REDIRECTED state. At this point, you

may confirm the redirection by calling the RvSipSubsSubscribe() function

again. You can also terminate the subscription using the RvSipSubsTerminate()

function.