Dialogic 05-2239-009 User Manual

Page of 604
Dialogic
®
 Global Call IP Technology Guide — November 2007
157
Dialogic Corporation
IP-Specific Operations
   else
   {  
      //only get tx or rx, not both
      l_pParmData = gc_util_find_parm(gcParmBlk, IPSET_MEDIA_STATE, IPPARM_RX_CONNECTED);
      if(l_pParmData != NULL)
      {
         memcpy(&l_IPCap, l_pParmData->value_buf, l_pParmData->value_size);
      }
   }
}
4.6.3
Getting Notification of Underlying Protocol State Changes
The application can receive notification of intermediate protocol signaling state changes for both 
H.323 and SIP. The events for this notification must be enabled; see 
Once these events are enabled, when a protocol state change occurs, the application receives a 
GCEV_EXTENSION event. The EXTENSIONEVTBLK structure pointed to by the extevtdatap 
pointer within the GCEV_EXTENSION event will contain the following information:
extID 
IPEXTID_IPPROTOCOL_STATE
parmblk 
A GC_PARM_BLK containing the protocol connection status with the 
IPSET_IPPROTOCOL_STATE parameter set ID and one of the following parameter IDs:
IPPARM_SIGNALING_CONNECTED – The signaling for the call has been established 
with the remote endpoint. For example, in H.323, a CONNECT message was received by 
the caller or a CONNECTACK message was received by the callee. 
IPPARM_SIGNALING_DISCONNECTED – The signaling for the call has been 
terminated with the remote endpoint. For example, in H.323, a RELEASE message was 
received by the terminator or a RELEASECOMPLETE message was received by peer. 
IPPARM_CONTROL_CONNECTED – Media control signaling for the call has been 
established with the remote endpoint. For example, in H.323, an OpenLogicalChannel 
message (for the receive direction) or an OpenLogicalCahnnelAck message (for the 
transmit direction) was received. 
IPPARM_CONTROL_DISCONNECTED – Media control signaling for the call has been 
terminated. For example, in H.323, an EndSession message was received. 
Note: The parameter value field in this GC_PARM_BLK in each case is unused (NULL).
4.7
Modifying an Existing SIP Call via re-INVITE 
This section discusses the Dialogic
®
 Global Call API implementation of the SIP re-INVITE 
method as it applies to first party call control (1PCC). The use of re-INVITE in the context of third 
party call control (3PCC) is discussed in 
This section includes the following topics: