Section: 4.15.13.3.3 Member UE Selection Assistance with QoS filtering criteria for real-time QoS Monitoring
Content: At the reception of Nnef_MemberUESelectionAsistance_Subscribe request of step 1, in order to detect the list of UEs that fulfil the QoS filtering criteria in real time, NEF performs real-time QoS monitoring. Unless the QoS flow to be monitored is associated with a default QoS flow, QoS Monitoring needs to be activated in SMF for that QoS Flow before (e.g. by AF Session with required QoS) (see clause 4.15.4.5.1 for details). Figure 4.15.13.3.3-1: 5GC assistance to Member UE selection for real-time QoS monitoring 1. AF subscribes to the Member UE selection assistance functionality by sending Nnef_MemberUESelectionAssistance_subscribe request including its AF ID, a list of target UE(s) and the QoS filtering criteria. 2. NEF uses the AF ID to verify the authorization of the AF request and identifies which information needs to be collected based on the QoS filtering criteria provided by the AF. 3. If S-NSSAI/DNN are not included in the request from the AF, the NEF derives the S-NSSAI and DNN which this Application has access to. NEF discovers the SMFs that are deployed in the Area of Interest by querying UDM and NRF. The NEF may also restrict the discovery to those SMFs that serve some S-NSSAI and DNN combination. 4. For each target SMF, NEF sends an Nsmf_EventExposure_Subscribe request (Event: 'QoS monitoring', target member UEs, optionally a traffic descriptor (e.g. Application ID), optionally indication for default QoS flows monitoring, S-NSSAI, DNN, Notification Target Address set to NEF, etc.). Alternatively, NEF may send an Nudm_EventExposure_Subscribe request to the UDM (not shown in Figure 4.15.13.3.3-1). 5. The SMF may need to send an N4 Session Modification request to UPF for requesting the QoS monitoring for certain flows. 6. UPF sends an Nupf_EventExposure_Notify request to NEF including an Event Exposure notification, according to the subscription received from SMF. 7. Based on the Event Exposure reports received from the UPFs, NEF consolidates the received results and derives the list(s) of candidate UE(s) and additional information which fulfil the QoS filtering criteria provided by the AF. 8. NEF sends a Nnef_MemberUESelectionAssistance_Notify request to the AF including the list(s) of candidate UE(s) and additional information.