n from non-3GPP networks. It also translates information between the AF and the 5GS. It masks network and user information for external AFs based on the network policy. End-to-End Architecture Components, Concepts, Security, and Transport Figure 2.8 - NEF reference points The NEF can also support PFD storage, which it retrieves from the UDR and can supply to the SMF using a push or pull method based on the request from the SMF. Network Data Analytics Function (NWDAF) analytics can be securely exposed to AFs using the NEF. The NWDAF can also retrieve information about the AF via the NEF. It can also support non-IP-based delivery. The NRF The Network Repository Function (NRF) is used for service discovery. It receives an NF discovery request from the NF instance or Service Communication Proxy (SCP) and provides the requested information to the requesting NF or SCP, whichever applies. It can be used to discover P-CSCF for IMS calls. It maintains a profile of all the NFs that are registered with it and maintains a record of the services they offer. It maintains the health of the NFs it discovers and keeps track of the load information. It notifies the already registered NFs of any new NF registration and informs the other NFs about the services available from new NFs. In the case of network slicing, multiple NRFs can be deployed at the PLMN level, the shared slice level, or a slice-specific level. The NRF maintains the following information on registered NFs: NF instance IDs NF types PLMN IDs Network slice identifiers IP addresses or FQDNs of the NFs 5G network concepts NF capacity information NF priority information NF set IDs Names of supported services, if applicable Endpoint addresses of instances of each supported service NF load information Routing indicators for the UDM and AUSF GUAMIs for the AMF SMF area identities for the UPF UDM group IDs UDR group IDs AUSF group IDs PCF group IDs HSS group IDs Supported analytics IDs Event IDs supported by AFs for the NEF Application identifiers supported by the AFs for t