BSF

binding support function

The binding support function (BSF), which is co-located with session management function (SMF), is used to discover the PCF serving the UE based on the UE IP address. This is done using the service operation, Nbsf_Management_Discovery, where the query parameters of the GET request contain the IP address of the UE. The IP domain attribute may be used in the query of the same UE IP address and may be used in a different IP domain. If a matching PDU session is found, the BSF returns the PCF identity either as an FQDN or IP address. The BSF may also return a PCRF identify using the Diameter host and realm. The UE IP address is served by the PCRF.