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

Working with Call-legs (Dialogs) 43

WORKING WITH CALL-LEGS (DIALOGS)

INTRODUCTION A call-leg is a peer-to-peer SIP relationship between two User Agents (UAs)

that persists for some time.

The Call-leg API relates to the following entities:

 Call-leg (call-leg)

 Call-leg Manager (Call-legMgr)

CALL-LEG A call-leg represents a SIP dialog as defined in RFC 3261, and is uniquely

identified by the Call-ID, From and To tags. Your application can initiate calls,

react to incoming calls and disconnect calls using the Call-leg API. The API

functions enable you to send and receive messages with different methods, such

as INFO, and to respond to such messages. A call-leg is a stateful object which

can assume any state from a set defined in the Call-leg API. A Call-leg state

represents the state of the session set up between two SIP UAs.

CALL-LEG

ANAGER

The Call-legMgr manages the collection of all call-legs. The Call-legMgr is

mainly used for creating new call-legs.

WORKING WITH

ANDLES

All call-legs and the Call-legMgr are identified using handles. You must supply

these handles when using the Call-Leg API. RvSipCallLegMgrHandle defines

the Call-legMgr handle. You receive this handle by calling

RvSipStackGetCallLegMgrHandle().

RvSipCallLegHandle defines a call-leg handle. For outgoing calls, you receive

the call-leg handle from RvSipCallLegMgrCreateCallLeg(). For incoming calls,

you receive the call-leg handle from the RvSipCallLegCreatedEv() callback.