6.3.28 NSSF discovery and selection

The following mechanisms may be used for discovery of NSSF service instances and their endpoint addresses in the serving network:

• NF consumer (i.e. AMF) or SCP may have all the NSSF services instances and their endpoint addresses locally configured.
• NF consumer (i.e. AMF) or SCP may utilise the NRF discovery service to discover the NSSF(s) and get the NF profile(s) of the NSSF(s). In this case, NSSF discovery and selection uses a PLMN-level NRF (i.e. not a slice-specific).

NOTE: Location information as defined in clause 6.3.1.2 can be used by the NF consumer for selecting an NSSF.

For an NSSF in visited network to discover and select an NSSF in home network, NSSF services instances and their endpoint addresses of the home NSSF is either locally configured in the visited NSSF or are discovered based on the self-constructed FQDN as specified in TS 23.003 [19].