Content for  TS 23.278  Word version:  18.0.0

When the HSS updates the CSI for a subscriber in the IP Multimedia CN subsystem, the HSS shall send a Notify Subscriber Data Change to the IM-SSF if all of the following conditions are true:

• The IM CSI data is marked with the Notification Flag
• The IM-SSF address is included in the gsmSCF address list

The IM-SSF address shall be added in the gsmSCF address list at the HSS for notification of IM-CSI updates if one of the following conditions occurs:

1. The HSS is notified of the subscriber's registration at the S-CSCF (via Cx interface), and the subscriber is provisioned with IM CSI data.
2. Operator provisions HSS subscriber data with IMS CAMEL service while the subscriber is currently registered in the IMS network i.e. one or more IM CSI data is added to the subscriber's profile in the HSS.
3. The HSS is notified of mobile termination for an unregistered subscriber (via Cx interface), and the subscriber is provisioned with IM CSI data

The IM-SSF address shall be deleted from the gsmSCF address list when the HSS initiates, or is notified of, the UE's deregistration. The IM-SSF address in the gsmSCF address list may be changed when the HSS receives a notification of a registration for a UE with a S-CSCF name different from the previously assigned S-CSCF name (i.e. re-registration from HSS point of view). The HSS shall overwrite the existing IM-SSF address with the IM-SSF address associated with the new S-CSCF name. The HSS procedure for sending the Notify Subscriber Data Change to the IM-SSF is the same procedure used for notifying the gsmSCFs in the Circuit Switched CN. This procedure is described in Procedure CAMEL_NSDC_HLR specified in TS 23.078 Rel-99[4]. The process specific to IM-SSF's handling of the Notify Subscriber Data Change is specified in this clause:

• Process Update_CSI