Section: 5.2.26.2 Nupf_EventExposure Service 5.2.26.2.1 General
Content: Service description: This service can expose UPF related information to other NFs. There are several operations for this service: - Notifying events on the PDU Session to the NFs. - Allow consumer NFs to subscribe and unsubscribe for an Event ID on UPF. The following events can be notified to a NF consumer: - QoS Monitoring. This event provides QoS Flow level performance information and can be used for direct event notification of QoS Monitoring reports to a different NF than the SMF as defined in clause 5.8.2.18 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2], or it may be for UPF Data collection by NWDAF for analytics (see TS 23.288[ Architecture enhancements for 5G System (5GS) to support network data analytics services ]  [50]) as described in clause 4.15.4.5. Subscription to this event is always indirect via SMF. The subscription specifies the type of measurement that is being requested. A combination of the information listed below can be requested. UPF and SMF interact using Session Reporting Rules as defined in clause 5.8.5.11 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2]. The event notification may contain following information: - QoS monitoring result for the QoS parameter(s) to be measured defined in clause 5.45 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2], e.g. UL packet delay, DL packet delay, or round trip packet delay. - Indication of QoS Flow associated with the default QoS Rule (if requested by SMF, see clause 4.15.4.5.1). - UserDataUsageMeasures. This event provides information of user data usage of the User PDU Session. It can be used for UPF Data Collection by NWDAF for analytics (see TS 23.288[ Architecture enhancements for 5G System (5GS) to support network data analytics services ]  [50]) as described in clause 4.15.4.5. SMF and other allowed direct consumers shall use Service Based Interface subscription service operation to subscribe this UPF event. The subscription request specifies type of measurement that is being requested and for which target traffic, which is either the whole PDU Session or traffic identified by either Application Id or traffic filter information and the required granularity for the information reported. A combination of the information listed below can be requested. The event notification may contain following information: - Volume Measurement: measures of data volume exchanged (UL, DL and/or overall) and/or number of packets exchanged (UL, DL and/or overall) with or without application granularity. - Throughput Measurement: measures of data throughput (UL and DL) measures aggregated for the PDU Session or per application. - Application related Information: URL/s and/or Domain information (domain name and protocol) detected for the target traffic. When the subscription requests that information is provided per data flow, the notification includes the packet filter set and the Applications Identifier if available. - UserDataUsageTrends. This event provides statistical measurements. It can be used for UPF Data Collection by NWDAF for analytics (see TS 23.288[ Architecture enhancements for 5G System (5GS) to support network data analytics services ]  [50]) as described in clause 4.15.4.5. SMF and other allowed direct consumers shall use SBI subscription operation to subscribe this UPF event. The subscription specifies for which target traffic the information is requested, which is either the whole PDU Session or traffic identified by either Application Id or traffic filter information and the required granularity for the information reported. The event notification may contain following information: - Throughput Statistic Measurement (average and/or peak throughput) over the measurement period for the PDU Session or per application. When the subscription requests that information is provided per data flow, the notification includes the packet filter set and the Applications Identifier if available. - TSC management information (UMIC, PMIC, NW-TT port number) as defined in clause 5.8.5.14 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2]. TSC management information event can be the result of an implicit subscription of the PCF on behalf of the TSNAF/TSCTSF via the Npcf_SMPolicyControl service as described in clause 5.28 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2]. If the consumer of UPF service is NWDAF and the target of UE is any UE, according to the Analytic ID from consumer, the NWDAF can decide which kind of information should be collect from UPF and event ID to use. Subscription may be performed directly towards UPF or via SMF as described in clause 4.15.4.5. The UPF collects the data according to the event ID and exposes the related information directly regardless of whether the subscription has been relayed by the SMF.