AF Notify NEF, AMF, and NWDAF Parameter Update Request/Response NEF and AMF Provision Create Request/Response Delete Request/Response Request/Response NIDDAuthorisation Request/Response UpdateNotify Subscribe/Notify Figure 3.14 - Services produced by the UDM The Nudm_SDM_Subscribe service operation can be leveraged by consumer NFs to receive notifications of updates in the subscription data. The (Nudm_SDM_Unsubscribe service operation can be leveraged by consumer NFs to stop receiving updates on changes in subscription data for a UE. The NudmUEAuthentication service is used by the consumer NF to get authentication information and provide information about the result of the authentication process. With the Nudm_EventExposure service, the consumer - in this case, the NEF - can subscribe to a particular event from the UDM, and the event IDs can help the consumer request specific events that it wants to be notified of. Building Blocks - Cloud Native Infrastructure The NudmParameterProvision service is used particularly by the NEF to provision and update information relating to the UE, such as 5G-VN group data or enhanced coverage restriction information. UDR services As we explored in Chapter 2, the UDR serves as the repository of subscription data. The details related to subscription are retrieved by network function consumers by querying the UDR. Hence, like any regular database, keys are used to retrieve datasets related to each user. The most common data key is the Generic Public Subscription Identifier (GPSI) or SUPI. Figure 3.15 lists the exposure data stored in the UDR: Category Information Data key Data sub key Access and mobility information UE location SUPI or GPSI UE time zone SUPI or GPSI UE access type SUPI or GPSI UE RAT type SUPI or GPSI UE registration state SUPI or GPSI UE connectivity state SUPI or GPSI UE reachability status SUPI or GPSI UE SMS over NAS service status SUPI or GPSI UE roaming status SUPI or GPSI UE current PLMN SUPI or GPSI Session management UE IP address SUPI or GPSI PDU session I