Section: 4.15.4.5.2 Information flow for subscription to UPF event exposure service for certain UE(s) via SMF
Content: Figure 4.15.4.5.2-1: Subscription to UPF event exposure service for certain UE(s) via SMF In the case of a group of UEs, the UPF event consumer (e.g. NWDAF) first issues an Nnrf_NFDiscovery_Request service operation to find the UDM providing the target Group ID and gets the NF profile of the UDM serves this group. Then, NWDAF obtains the list of SUPIs that correspond to the Group ID from UDM using Nudm_SDM_Get NOTE 1: It is assumed that all members of a Group ID belong to the same UDM. Then, for each SUPI: 1. The UPF event consumer (e.g. NWDAF) invokes Nudm_UECM_Get service operation to retrieve the appropriate SMF by providing UE ID, DNN, S-NSSAI and NF type = SMF. 2. The UDM provides a Nudm_UECM_Get response with the corresponding SMF. 3. The UPF event consumer sends the Nsmf_EventExposure Subscription request to the SMF to subscribe to UPF data, including the following information: - Notification Target Address (UPF event consumer address), Notification Correlation Information. - Indication of UPF Event Exposure Service and Target subscription UPF Event Id. - Event Filter Information: S-NSSAI, DNN, DNAI,UPF Id, Traffic Description for the target traffic (e.g. Application Id), Area of Interest, SSID/BSSID. - Target of Event Reporting: a UE. - Reporting suggestion information. - Target Subscription information: Type of Measurement and granularity of the information requested. If the consumer is NWDAF and the analytic filter information includes application server IP address/FQDN, the NWDAF may need to first obtain the DNAI from NEF as described in steps 2 and 3 in Figure 4.15.4.5.3-1. 4. The SMF selects the PDU session(s) and the UPFs it has to send the request to. The SMF sends the request to the UPF including the UPF event consumer address, Notification Correlation Information, Event Filter Information, Reporting suggestion information, Target of Event Reporting and Target Subscription Information as required. Target of Event Reporting is a certain UE. The interaction mechanism used between SMF and UPF depends on UPF exposure event and which mechanism applies for each event as described in clause 5.2.26.2.1. For some events, the SMF shall contact UPF (4a) with N4 Session Modification with PFCP (TS 29.244[ Interface between the Control Plane and the User Plane nodes ]  [69]), for other events (4b) with Nupf_event exposure subscribe request (as defined in clause 5.2.26.2.3). NOTE 2: Some events can require SMF interacts with RAN at this stage. 5. Per Reporting suggestion information (if available), the UPF sends the locally collected UPF data by invoking Nupf_EventExposure_Notify service operation to the UPF event consumer.