Section: 4.16.14.2.2 Management of access and mobility related policy information at SM Policy Association establishment and termination with the notification sent by the BSF
Content: Figure 4.16.14.2.2-1: Management of access and mobility related policy information at SM Policy Association establishment and termination with the notification by the BSF 1. The AMF establishes an AM Policy Association for retrieving access and mobility related policy information, e.g. RFSP index value, as described in clause 4.16.1.2. 2. If the access and mobility related policy information depend on the SM Policy Association establishment and termination for a DNN, S-NSSAI combination, then depending on operator policies in the PCF, the PCF may subscribe to BSF and then step 3 follows, or the PCF may provide its PCF binding information to the AMF with the indication to be notified about the PCF for the PDU Session for a DNN, S-NSSAI and then step 4 follows. 3. The PCF for the UE determines that access and mobility related policy information (e.g. RFSP index value) depend on the detection of SM Policy Association establishment associated with the (DNN, S-NSSAI) combinations configured in the PCF or retrieved from the UDR as part of the Application Data Set. The PCF for the UE then subscribes to the BSF to be notified when a PCF for the PDU Session is registered for the first SM Policy Association establishment and the PCF for the PDU Session is deregistered for the last SM Policy Association termination to the same (DNN, S-NSSAI) combination in the BSF, by invoking Nbsf_Management_Subscribe (SUPI, list of (DNN, S-NSSAI)(s), indication of registration/deregistration per (DNN, S-NSSAI)). 4. The SMF establishes a SM Policy Association as described in clause 4.16.4. The allocated UE address/prefix, SUPI, DNN, S-NSSAI and the PCF address are registered in the BSF, as described in clause 6.1.1.2.2 of TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [20]. 5. If the PCF for the UE subscribed to BSF, then the BSF notifies a PCF registration when the first SM Policy Association corresponding to the (DNN, S-NSSAI) combination is established, by invoking Nbsf_Management_Notify (DNN, S-NSSAI, notification of registration). 6. The PCF checks operator policies and then may change access and mobility related policy information (e.g. RFSP index value) based on the reporting of SM Policy Association establishment. 7. The SM Policy Association is terminated as described in clause 4.16.6 and the allocated UE address/prefix, SUPI, DNN, S-NSSAI and the PCF address are deregistered in the BSF. 8. If the PCF for the UE subscribed to BSF, then BSF notifies of a PCF deregistration when the last SM Policy Association corresponding to the (DNN, S-NSSAI) combination is terminated, by invoking Nbsf_Management_Notify (DNN, S-NSSAI, notification of deregistration).