9.4.2 Procedure OR_Handle_RCH

23.0793GPPRelease 17Support of Optimal Routeing (SOR)Technical realizationTS

Sheet 1: if the GMSC receives O-CSI or D-CSI in Resume Call Handling, then the GMSC shall verify whether it supports the CAMEL Phases indicated in O-CSI and D-CSI. If either or both of O-CSI and D-CSI indicates CAMEL Phase 4, then the GMSC shall also verify whether the Offered CAMEL4 CSIs of the GMSC includes support for O-CSI and D-CSI. If the required CAMEL Phases or the required CAMEL4 CSIs are not supported in the GMSC, then the GMSC disallows the Optimal Routeing request. Refer to 3GPP TS 23.078 [7] for a description of the Offered CAMEL4 CSIs.

Sheet 1: if the GMSC interrogates the HLR for a Forwarded-to number, the Routeing address is the Forwarded-to number received in the Send Routeing Info ack; otherwise the Routeing address is the Forwarded-to number received in the Resume Call Handling.

Sheet 1: the task "Destination address := FTN" is executed only if the GMSC supports optimal routeing of basic mobile-to-mobile calls.

Sheet 1: the procedure Route_permitted is called to verify the number received in Resume Call Handling or the number received from HLR. If the result is "False", then the GMSC disallows the Optimal Routeing. The call forwarding will now be done by the VMSC.

Note When the procedure Route_permitted returns result "False", then the gsmSCF is not informed about the forwarding and can therefore not provide an alternative destination address. Reason is that once the gsmSCF is informed about forwarding, the call forwarding can not be returned to the VMSC.

Sheet 2: the procedure CAMEL_MT_GMSC_Notify_CF is specific to CAMEL phase 2 or higher; it is specified in 3GPP TS 23.078 [7]. If the GMSC does not support CAMEL phase 2 or higher, processing continues from the "Continue" exit of the test "Result".

If the result of the procedure CAMEL_MT_GMSC_Notify_CF is "Fail" or "Release", then the call will be released.

If the result of the procedure CAMEL_MT_GMSC_Notify_CF is "Reconnect", then the GMSC allows the Optimal Routeing. The GMSC will then start a call forwarding process.

Sheet 2: when the procedure Route_permitted on sheet 1 returns result "False", then the GMSC returns "OR not allowed" to the VMSC. The call forwarding will now be done by the VMSC.

Sheet 3: the procedure Activate_CF_Process is specified in 3GPP TS 23.018 [6]. When procedure Activate_CF_Process returns result "Release" or "Fail", the call is released.

If the result is "Pass", then the GMSC allows the Optimal Routeing.

Sheet 3: the procedure UUS_GMSC_Check_Forwarding is specific to UUS; it is specified in 3GPP TS 23.087 [9].

Sheet 3: the procedure CAMEL_Store_Destination_Address is specific to CAMEL phase 3 or higher; it is specified in 3GPP TS 23.078 [7].

Sheet 3: the called party address sent in the IAM to the process MT_CF_MSC is the Forwarded-to number received in the Perform Call Forwarding ack.

Sheet 3: the process MT_CF_MSC is specified in 3GPP TS 23.018 [6].