Content for  TS 23.015  Word version:  18.0.0

If barring of roaming is applied to a subscription (or modified or removed) by administrative action in the HLR/HSS/UDM, the HLR/HSS/UDM shall update the subscription information accordingly. If the HLR/HSS/UDM determines from the identity of the VLR and/or the SGSN and/or MME and/or the AMF that the mobile subscriber is currently registered in a barred PLMN, the HLR/HSS/UDM shall put the barring into effect by using a Cancel Location operation to the VLR and/or the SGSN and /or to the MME when applied in HLR/HSS or a UECM Deregistration to AMF when applied in UDM, as shown in Figure 2.3.1-1. In the 5G Core case, barring of roaming may be stored in UDR. Upon change of barring of roaming in UDR, UDM clears also user registration in UDR using Nudr_DM_Update operation and unsubscribes to changes on barring of roaming data using Nudr_DM_Unsubscribe operation. If the mobile subscriber is not currently registered in a barred PLMN, the HLR/HSS/UDM shall take no further action.

Barring of roaming is invoked in the HLR/HSS/UDM. If the HLR receives a request from a VLR for location updating for a mobile which is attempting to roam to an area prohibited by Operator Determined Barring, the HLR shall reject the location updating request with an appropriate error indication and this error indication shall be relayed by the MSC and the BSS/RNS to the mobile station over the radio path. If the HLR receives a request from a SGSN for location updating for a mobile which is attempting to roam to an area prohibited by Operator Determined Barring, the HLR shall reject the location updating request with an appropriate error indication and this error indication shall be relayed by the SGSN and the BSS/RNS to the mobile station over the radio path. If the HSS receives a request from a MME for location updating for a mobile which is attempting to roam to an area prohibited by Operator Determined Barring, the HSS shall reject the location updating request with an appropriate error indication and this error indication shall be relayed by the MME to the mobile station over the radio path. If the UDM receives a request from an AMF for 5G registration for a user equipment who is attempting to roam to an area prohibited by Operator Determined Barring, the UDM shall reject the registration request with an appropriate error indication and this error indication shall be relayed by the AMF to the user equipment over the radio path. In the 5G Core case, barring of roaming can be optionally stored in UDR. Upon change of barring of roaming in UDR, UDM clears also user registration in UDR using Nudr_DM_Update operation and unsubscribes to changes on barring of roaming data using Nudr_DM_Unsubscribe operation. Indicative message flow diagrams for the handling of Operator Determined Barring of roaming are given in Figure 2.3.2-1, Figure 2.3.2-2, Figure 2.3.2-3 and Figure 2.3.2-4.