Section: 5.2.2.3 Namf_EventExposure service 5.2.2.3.1 General
Content: Service description: This service enables an NF to subscribe and get notified about an Event ID. Following UE access and mobility information event are considered (Event ID is defined in clause 4.15.1 and Table 4.15.3.1-1): - Location Report (TAI, Cell ID, N3IWF/TNGF node, UE local IP address and optionally UDP source port number); - UE moving in or out of a subscribed "Area Of Interest" as described in clauses 5.3.4.4 and 5.6.11 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2]; - Number of UEs served by the AMF and located in "Area Of Interest"; - Time zone changes (UE Time zone); - Access Type changes (3GPP access or non-3GPP access); - Registration state changes (Registered or Deregistered); - Connectivity state changes (IDLE or CONNECTED); - UE loss of communication; - UE reachability status; - UE indication of switching off SMS over NAS service; - Subscription Correlation ID change (implicit subscription); - UE Type Allocation code (TAC); - Frequent mobility re-registration; - Subscription Correlation ID addition (implicit subscription); - User State Information in 5GS, as described in clause 5.4.4 of TS 23.632[ User data interworking, coexistence and migration; Stage 2 ]  [68]; - UE access behaviour trends (see clause 4.15.4.2); - UE location trends (see clause 4.15.4.2); and - Total number of Mobility Management transactions: - The Total number of Mobility Management transactions is used to collect the number of MM transactions of a SUPI or Internal Group ID, for example Dispersion Analytics as specified in TS 23.288[ Architecture enhancements for 5G System (5GS) to support network data analytics services ]  [50]. The Total number of transactions is incremented when the NAS signalling transactions from Authentication, Registration, De-Registration, Service Request and UE Configuration Update procedures is completed. Only the periodic reporting mode applies. In addition to UE access and mobility information event, AMF exposes the "S-NSSAIs per TAI mapping" event providing, per TAI, the related access type and list of supported S-NSSAIs (including indication of S-NSSAIs restricted by AMF). The Event Consumer may use as target of event reporting a list of TAIs, or "any TAI" and may use event filter information including a list of "S-NSSAIs". Whenever there is a change in supported S-NSSAIs (including indication of S-NSSAIs restricted by AMF) for a TAI, the event notification is generated with the updated information. Event Filters are used to specify the conditions to match for notifying the event (i.e. "List of Parameter values to match"). If there are no conditions to match for a specific Event ID, then the Event Filter is not provided. The following table provides some examples on how the conditions to match for event reporting can be specified for various Event IDs for AMF exposure. NOTE: The conditions to match can be set based on AMF-associated expected UE Behaviour parameter(s) to only notify the event when the UE's behaviour deviates from its expected UE behaviour as described in TS 23.288[ Architecture enhancements for 5G System (5GS) to support network data analytics services ]  [50]. Table 5.2.2.3.1-1: Example of Event Filters for AMF exposure events The following service operations are defined for the Namf_EventExposure service: - Namf_EventExposure_Subscribe. - Namf_EventExposure_UnSubscribe. - Namf_EventExposure_Notify.