4.15.10 AF specific UE ID retrieval

23.5023GPPProcedures for the 5G System (5GS)Release 18TS

This clause contains the detailed description and the procedures for the AF specific UE ID retrieval. The AF specific UE Identifier is represented by the External Identifier as defined in TS 23.003 [33].

NOTE 1: After retrieving AF specific UE ID, the AF can invoke NEF provided services (e.g. location monitoring).

Figure 4.15.10-1: AF specific UE ID retrieval

1. AF requests to retrieve UE ID via the Nnef_UEId_Get service operation. The request message shall include UE address (IP address or MAC address) and AF Identifier, it may include, MTC Provider Information, Application Port ID, IP domain. The MTC Provider Information identifies the MTC Service Provider and/or MTC Application. If available the AF may also provide the corresponding DNN and/or S-NSSAI.

NOTE 2: The MTC Provider Information can be used by any type of Service Providers (MTC or non-MTC) or Corporate or External Parties for, e.g. to distinguish their different customers.

NOTE 3: The case where UE IP address provided by the AF to the NEF corresponds to an IP address that has been NATed (Network and Port Address Translation) is not supported in this release.

NOTE 4: The Application Port ID is as defined in Nnef_Trigger_Delivery.

NOTE 5: The NEF can validate the provided MTC Provider Information and override it to a NEF selected MTC Provider Information based on configuration. How the NEF determines the MTC Provider Information, if not present, is left to implementation (e.g. based on the requesting AF).

2. The NEF authorizes the AF request. If the authorisation is not granted, the NEF replies to the AF with a Result value indicating authorisation failure; otherwise the NEF proceeds with the following steps. The NEF determines corresponding DNN and/or S-NSSAI information: this may have been provided by the AF or is determined by the NEF based on the requesting AF Identifier, MTC Provider Information.

3-4. The NEF uses the Nbsf_Management_Discovery service operation with UE address and IP domain and /or DNN and/or S-NSSAI to retrieve the session binding information of the UE. If no SUPI is received in the session binding information from the BSF, the NEF replies to the AF with a Result value indicating that the UE ID is not available.

5. The NEF interacts with UDM to retrieve the AF specific UE Identifier via the Nudm_SDM_Get service operation. The request message includes SUPI and at least one of Application Port ID, MTC Provider Information or AF Identifier.

6. The UDM responds to the NEF with an AF specific UE Identifier represented as an External Identifier for the UE which is uniquely associated with the Application Port ID, MTC provider Information and/or AF Identifier.

7. The NEF further responds to the AF with the information (including the AF specific UE Identifier represented as an External Identifier) received from the UDM.