Dialogic IP Phone 05-2239-009 User Manual

259

Dialogic Corporation

An application has no ability to specify which H.225 message types it wishes to receive UU-IE in, 
and should therefore be capable of handling UU-IE contained in any of the specified H.225 
message types. 

The maximum data length for the Global Call parameter used for the UU-IE content is configured 
at system start-up. The maximum data length for this parameter is configured by setting the 
max_parm_data_size field in the IPCCLIB_START_DATA structure. The default size is 255 bytes 
(for backwards compatibility), but applications may configure it to be as large as 4096 bytes. 
Applications must use the extended gc_util_..._ex( ) functions to extract any GC_PARM_BLK 
parameter elements whose data length has been configured to be greater than 255 bytes. 

The ability to retrieve UU-IE from inbound H.225 messages is an optional feature that is enabled or 
disabled on a virtual board basis at the time the gc_Start( ) function is called. 

The mandatory 

 function populates the 

with default values. The default value of the h323_msginfo_mask field in the IP_VIRTBOARD 
structure does not enable access to any of the supported additional information types (Q.931 
message information elements, tunneled signaling messages, or User-to-User information 
elements). To enable any of these features for an ipt device, the default value of the 
h323_msginfo_mask field must be overridden with a value that represents the appropriate logical 
combination of the defined mask values. To enable access to User-to-User IEs, the value 
IP_H323_RETRIEVE_UUIE_ENABLE must be set in the mask. The following code snippet 
enables Q.931 message IE access on two virtual boards and enables UU-IE access on the second 
board only: 

INIT_IPCCLIB_START_DATA(&ipcclibstart, 2, ip_virtboard); 
INIT_IP_VIRTBOARD(&ip_virtboard[0]); 
INIT_IP_VIRTBOARD(&ip_virtboard[1]); 
ip_virtboard[0].h323_msginfo_mask = IP_H323_MSGINFO_ENABLE; 
                                    /* override Q.931 message default */
ip_virtboard[1].h323_msginfo_mask = IP_H323_MSGINFO_ENABLE | 

 

IP_H323_RETRIEVE_UUIE_ENABLE; 

                                    /* override Q.931 message and UU-IE defaults */

Features that are enabled or configured via the IP_VIRTBOARD structure cannot be disabled or 
reconfigured once the library has been started. All items set in this data structure take effect when 
the gc_Start( ) function is called and remain in effect until gc_Stop( ) is called when the 
application exits. 

Table 17 relates the supported H.225 messages that can contain UU-IE fields to the Global Call 
event types that are used to notify the application of the message’s arrival. 

Setup

GCEV_OFFERED

Proceeding

GCEV_PROCEEDING †

Alerting

GCEV_ALERTING

† The GCEV_PROCEEDING event is maskable.