In order to make sure the AF can query for DNAIs, the 5GS may help determine proper DNAI(s) and notify the information to AF based on AF request providing EAS address information (i.e. IP address(es), EAS IP range(s) or FQDN(s)).
NEF/UDR is configured by OAM with the mapping information between EAS IP address information and DNAI. AF may subscribe the mapping information modification to NEF. AF may request immediate reporting. When the configuration information (relationship between DNAI and EAS address information) is changed, the UDR can notify the new mapping information to NEF. When the mapping information is stored in UDR, NEF may subscribe to mapping information in UDR, where NEF may request immediate reporting. If subscribed to information change, the UDR notifies the NEF with all the corresponding mapping information it has stored for the relevant DNN and/or S-NSSAI, and the NEF notifies the AF.
The EAS address and DNAI Mapping Information record in UDR is shown Table 6.8.1-1
. The information elements for the NEF service Nnef_DNAIMapping_Subscribe
is specified in clause 18.104.22.168 of TS 23.502
AF invokes Nnef_DNAIMapping_Subscribe
service to request the DNAI information. The request includes EAS address information and optionally: DNN, S-NSSAI, AF Identifier, and geographical area.
If mapping information is stored in NEF, skip step 2-3.
If the mapping information is stored in UDR, the NEF determines the DNN and/or the S-NSSAI if not received from the AF, potentially using the AF identifier. If the NEF has not yet received the DNAI mapping information for this DNN and/or S-NSSAI, NEF invokes the Nudr_DM_Subscribe service to subscribe to DNAI mapping information for this DNN and/or S-NSSAI.
UDR notifies the NEF with all the DNAI mapping information for the requested DNN/S-NSSAI.
NEF determines the suitable DNAI(s) using the DNAI mapping information.
NEF notifies the DNAI(s) or the updated DNAI information to AF corresponding to the request in step 1.
If DNAI information is stored in the UDR, whenever the DNAI mapping information change, steps 3 to 5 take place.