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

272 HP-UX C SIP Stack Programmer’s Guide
REFER-Subscription API
 A REFER sent outside the context of a dialog—UA1 can create
an independent refer-subscription, and send the REFER to UA2
to establish a session with UA3, without connecting a call with
UA2 first.
REFER-
S
UBSCRIPTION API
The REFER-Subscription API includes a set of functions and function callbacks
that are dedicated to REFER implementation. These functions are called the
REFER-Subscription API. To implement REFER scenarios, you should use the
REFER-Subscription API together with the generic API functions of the
Subscription layer.
The REFER-Subscription API functions enable you to examine REFER
parameters, send, receive and accept REFER requests, and handle the NOTIFY
messages associated with the REFER request.
REFER-
SUBSCRIPTION
PARAMETERS
You can examine refer-subscription parameters via Subscription Get API
functions. The following parameters are available:
Refer To Header
The Refer-To header contains the address of the referenced party in a REFER
process. This address is updated from REFER requests that are sent or received
by the SIP Stack. You can set the Refer-To header to an outgoing REFER
request using the RvSipSubsReferInit() function. You can access the Refer-To
header of an incoming REFER request with a Get function. The header is not
modifiable.
Referred By Header
The Referred-By header contains the address of the party initiating the REFER
process (the referrer). This address is updated from REFER requests that are
sent or received by the SIP Stack. You can set the Referred-By header to an
outgoing REFER request using the RvSipSubsReferInit() function. You can
access the Referred-By header of an incoming REFER request with a Get
function. The header is not modifiable.
REFER-
S
UBSCRIPTION
C
ONTROL
The following API functions were added to the Subscription layer for REFER
control.