6.3.26 NRF discovery and selection

The following mechanisms may be used for discovery of NRF service instances and their endpoint addresses:

• NF consumers or SCP may have all the NRF services instances and their endpoint addresses locally configured.
• NF consumers or SCP may have the endpoint address of a NRF discovery service locally configured and utilize it to discover the NRF(s) and get the NF profile(s) of the NRF(s).
• NF consumers (e.g. v-NRF) or SCP may have endpoint addresses of the NRF bootstrapping service and utilize it to discover the NRF service instances and their endpoint addresses. The NRF bootstrapping service is a version independent API, which may be especially useful over roaming interfaces.
• The NF consumer, e.g. AMF, may use the Nnssf_NSSelection service to get the endpoint address of a NRF discovery service for a certain slice.