11.2.1 Procedures in GMSC

03.933GPPStage 2Technical realization of Completion of Calls to Busy Subscriber (CCBS)TS

Figure 11.2.1.1: Procedure CCBS_MT_GMSC_Check_CCBS_Call

This procedure checks from the IAM message whether the call is CCBS call. If that is the case the CCBS Call parameter is set to the Send Routeing Info message. This functionality shall be applied only to the initial call leg. The procedure initialises also the CCBS Possible variable as True, the variable is accessible to all CCBS specific procedures in the GMSC.

Figure 11.2.1.2: Procedure CCBS_MT_GMSC_Check_CCBS_Indicators

This procedure sets the CCBS_Call indicator to the outgoing IAM message when needed. This functionality shall be applied only to the initial call leg.

Figure 11.2.1.3: Procedure CCBS_MT_GMSC_Remove_Indicators_Store_FWT

This procedure removes CCBS_Call indicator from the forwarded IAM message and also stores the forwarding type. It also checks whether subscriber B can be target of CCBS Requests and stores that information for later use.

Figure 11.2.1.4: Procedure CCBS_MT_GMSC_Remove_Indicators

This procedure removes CCBS_Call indicator from the outgoing IAM message. CCBS activation is not possible for this call because T-CSI modified destination address.

Figure 11.2.1.5: Procedure CCBS_MT_GMSC_Check_CCBS_Possible

This procedure contains the core logic to handle various interactions with CAMEL, OR and received Release message content. The procedure alters CCBS specific global variable CCBS Target which controls setting of the diagnostic field in the Release message towards the originating network.

Global variables Reconnect and Resume Call are specific to CAMEL and OR interaction respectively. They are initialised and updated in the process MT_GMSC or MT_CF_MSC, refer to GSM 03.18.

Figure 11.2.1.1: Procedure CCBS_MT_GMSC_Check_CCBS_Call

Figure 11.2.1.2: Procedure CCBS_MT_GMSC_Check_CCBS_Indicators

Figure 11.2.1.3: Procedure CCBS_MT_GMSC_Remove_Indicators_Store_FWT

Figure 11.2.1.4: Procedure CCBS_MT_GMSC_Remove_Indicators

Figure 11.2.1.5: Procedure CCBS_MT_GMSC_Check_CCBS_Possible