21.9 Immediate Service Termination (IST)
29.0023GPPMobile Application Part (MAP) specificationRelease 17TS
21.9.1 IST Alert
The Immediate Service Termination Alert procedure is used to keep track of the call activities performed by subscribers who are marked as being subject to IST monitoring and, possibly, to terminate the call activities for which the alert was sent, or all the call activities related to the subscriber for whom the alert was sent.
The message flow for alerting is shown in figure 21.9/1; the MSC may be a Visited MSC or a Gateway MSC.
1) MAP_IST_ALERT_req/ind
2) MAP_IST_ALERT_rsp/cnf
Figure 21.9/1: Message flow for IST Alert
21.9.1.1 Procedure in the MSC
The MAP process in the MSC (Visited MSC or Gateway MSC) is shown in figure 21.9/3. The MAP process invokes macros not defined in this clause; the definitions of these macros can be found as follows:
Receive_Open_Cnf see clause 25.1.2;
Check_Confirmation see clause 25.2.2.
21.9.1.2 Procedure in the HLR
The MAP process in the HLR is shown in figure 21.9/4. The MAP process invokes a macro not defined in this clause; the definition of this macro can be found as follows:
Receive_Open_Ind see clause 25.1.1;
21.9.2 IST Command
The Immediate Service Termination Command procedure is used to terminate the call activities related to a subscriber.
The message flow for the IST Command procedure is shown in figure 21.9/2; the MSC may be a Visited MSC or a Gateway MSC.
1) MAP_IST_COMMAND_req/ind
2) MAP_IST_COMMAND_rsp/cnf
Figure 21.9/2: Message flow for IST Command
21.9.2.1 Procedure in the HLR
The MAP process in the HLR is shown in figure 21.9/5. The MAP process invokes macros not defined in this clause; the definitions of these macros can be found as follows:
Receive_Open_Cnf see clause 25.1.2;
Check_Confirmation see clause 25.2.2.
21.9.2.2 Procedure in the MSC
The MAP process in the MSC is shown in figure 21.9.6. The MAP process invokes a macro not defined in this clause; the definition of this macro can be found as follows:
Receive_Open_Ind see clause 25.1.1.
Figure 21.9/3: Process IST_Alert_MSC
Figure 21.9/4: Process IST_Alert_HLR
Figure 21.9/5: Process IST_Command_HLR
Figure 21.9/6: Process IST_Command_MSC