Section: 5.2.13.2.6 Nbsf_Management_Subscribe service operation
Content: Service Operation name: Nbsf_Management_Subscribe Description: NEF, AF, TSCTSF or PCF for a UE can subscribe to be notified of newly registered or deregistered PCF for a PDU Session. In addition, NEF or AF can subscribe to be notified of newly registered or deregistered PCF for a UE. NOTE 1: If BSF has already the requested information at the time of the subscription, it will accept the subscription request and will immediately provide the results in the Outputs parameters. Inputs, Required: SUPI, DNN(s) [Required, if PCF subscription is for a PDU Session], S-NSSAI(s) [Required, if PCF subscription is for a PDU Session], callback URI. Inputs, Optional: GPSI, indication of registration/deregistration per (DNN, S-NSSAI). Indication of registration/deregistration per (DNN, S-NSSAI) indicates to the BSF to report when the first SM policy association is established and when the last SM policy association is terminated to the same (DNN, S-NSSAI) combination. NOTE 2: It is up to stage3 to ensure an unambiguous error proof way for the BSF to differentiate between PCF for a PDU Session and PCF for a UE. This may or may not require providing the BSF additional input parameter(s). Outputs, Required: When the subscription is accepted: Subscription Correlation ID. Outputs, Conditional: One or more instance per (DNN, S-NSSAI) of (UE address(es) [If available], PCF address(es) [If available], PCF instance ID [If available], PCF Set ID [If available], level of Binding [If available] (see clause 6.3.1.0 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2])) or notification of registration/deregistration per (DNN, S-NSSAI). NOTE 3: The parameter UE address(es) is not applicable in the case of PCF for a UE.