5.2.26 UPF Services

23.5023GPPProcedures for the 5G System (5GS)Release 18TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

5.2.26.1 General

The following table shows the UPF Services and UPF Service Operations.

Table 5.2.26.1-1: NF services provided by the UPF

Service Name	Service Operations	Operation Semantics	Example Consumer(s)
Nupf_EventExposure	Notify	Subscribe/Notify	NEF, AF, NWDAF, TSNAF/TSCTSF
	Subscribe	Subscribe/Notify	NWDAF SMF
	Unsubscribe	Subscribe/Notify	NWDAF SMF

5.2.26.2 Nupf_EventExposure Service

5.2.26.2.1 General

Service description: This service can expose UPF related information to other NFs. There are serveral 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.

– Allow consumer NFs to acknowledge an event notification.

The following events can be notified to a NF consumer:

– QoS Monitoring. This event provides QoS Flow level performance information. For example, it can be used for URLLC: the event notification may contain the QoS Monitoring report as described in clause 5.33.3.2 of TS 23.501 [2], or for UPF Data collection by NWDAF for analytics (see TS 23.288 [50]).

The event notification may contain following information:

– QoS monitoring result e.g. end to end delay for specific QoS flow or for specific PDU session.

– QoS Flow Bandwidth measurements: It provides bitrate measurements (UL, DL and/or overall) for a PDU Session and QoS Flow.

– 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 [50]).

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. This measurement can also include number of packets transmitted for applications where that is possible to differentiate.

– Throughput Measurement: measures of data throughput (UL and DL) measures aggregated for the PDU Session or per application.

– UserDataUsageTrends. This event provides statistical measurements. It can be used for UPF Data Collection by NWDAF for analytics (see TS 23.288 [50]).

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.

– TSC management information (UMIC, PMIC, NW-TT port number) as defined in clause 5.8.2.11.14 of TS 23.501 [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. In the latter case, the SMF determines the UPF(s) towards which the final consumer subscription is to be relayed and sends the subscription request to UPF (as described in clause 4.15.11). The UPF collects the data according to the event ID, and exposes the related information directly regardless of whether the subscription has ben relayed by the SMF.

Editor’s note: The condition for a final consumer of UPF events to directly subscribe to UPF or to request SMF to do third party subscription are FFS.

5.2.26.2.2 Nupf_EventExposure_Notify service operation

Service operation name: Nupf_EventExposure_Notify

Description: This service operation reports the event and information to the consumer that has subscribed implicitly.

Input Required: Event ID, UE address (i.e. IP address or MAC address). Notification Correlation Information.

Input, Optional: UE ID, Event specific parameter as described in clause 5.2.26.2.1, time stamps for the measures and Application Id or Packet Filter Set.

Output Required: Result Indication.

Output, Optional: None.

5.2.26.2.3 Nupf_EventExposure_Subscribe service operation

Service operation name: Nupf_EventExposure_Subscribe

Description: This service operation is used by an NF to subscribe to UPF event exposure notifications e.g. for the purpose of UPF data collection on a specified PDU Session or for all PDU Sessions of one UE, group of UE(s) or any UE.

Input, Required: NF ID, Target of Event Reporting, (set of) Event ID(s) defined in clause 5.2.26.2.1, Notification Target Address (+ Notification Correlation ID), Event Reporting Information defined in Table 4.15.1-1.

Input, Optional: Subscription Correlation ID (in the case of modification of the event subscription), Expiry time, DNN, S-NSSAI, Application ID, Reporting suggestion information.

Output, Required: When the subscription is accepted: Subscription Correlation ID (required for management of this subscription), Expiry time (required if the subscription can be expired based on the operator’s policy).

Output, Optional: First corresponding event report is included, if available (see clause 4.15.1). Notification Target Address (+ Notification Correlation ID) is used to correlate Notifications sent by UPF with this subscription.

5.2.26.2.4 Nupf_EventExposure_UnSubscribe service operation

Service operation name: Nupf_EventExposure_UnSubscribe

Description: The NF consumer uses this service operation to unsubscribe for a specific event.

Input, Required: Subscription Correlation ID.

Input, Optional: None.

Output, Required: Operation execution result indication.

Output, Optional: None.

The NF consumer or the SMF on behalf of other NF unsubscribes the event notification by invoking Nupf_EventExposure_Unsubscribe (Subscription Correlation ID) to the UPF.