Welltech Dialogic SS7 Protocols ISUP - Manual (Page 19)

Dialogic ® SS7 Protocols ISUP Programmer's Manual Issue 15
19
4 Interface to System Services
4.1 System Functions
In addition to the primitive interfaces and the management interface to the
ISUP module (which are described in later sections) the module requires a
few basic system services to be supplied by the underlying operating system.
In most cases, this is achieved by the use of the appropriate Development
package.
The following functions are used for inter-task communication:
GCT_send Send a message to another task.
GCT_receive Receive the next message from the module’s input queue, blocking the task if
no message is ready.
GCT_grab As GCT_receive, but no blocking if no message is ready.
The following functions are required for message allocations for inter-task
communication:
getm Allocate a message from the system.
relm Release a message back to the system.
4.2 Timer Operation
In order to provide internal implementation of the ISUP protocol timers the
module needs to receive a periodic timer tick message. This is generated
either by the on-board timer module or the tick and tim binaries supplied as
part of the development package.
The following action request message is issued by the ISUP module:
KEEP_TIME Issued by ISUP to initialize timer services.
The ISUP module expects the following notification on a periodic basis from
the timer module:
TM_EXP Issued by the timer module to notify of periodic timer tick.
The format of these messages is described in Appendix F: Timer Services on
page 199 .