n ID(s) SMF-Associated expected UR behaviour parameters Suggested number of downlink packets ATSSS information Figure 3.13 - Subscription data contents The UDM provides the Nudm_UECM_Registration service operation, which is used to register the UE's serving network function when the network function type is the AMF or SMF. It also serves to register an NF service consumer in the UDM for a particular user. The NudmUECMDeregistrationNotification service operation is used by the UDM to notify any registered consumer that a particular NF consumer has been deregistered in the UDM. The admUECM_Deregistration service operation is used by an NF consumer to request that the UDM delete information related to itself in the UE context. The Nudm UECM Get service operation is used by the network function consumer to retrieve the NF ID of the NF service in this UE. REST in 5G The Nudm_UECM_Update service operation is used by the network function consumer to update UE information, such as device capabilities, and the SMF + PGW-c FQDN. The Nudm_SDM_Get service operation is used by the consumer to get subscription data related to a UE. The Nudm_SDM_Notification service operation informs network consumers of any updates to a subscription in a UE. NF Service Service Operations Operation Semantics Example Consumer(s) Subscriber Data Request/Response AMF, SMF, SMSF, NEF, 5G, and DDNMF Management Subscribe Subscribe/Notify AMF, SMF, SMSF, NEF, 5G, and DDNMF (SDM) Unsubscribe Subscribe/Notify AMF, SMF, SMSF, NEF, 5G, and DDNMF Notification Subscribe/Notify AMF, SMF, SMSF, NEF, GMLC, 5G, and DDNMF Request/Response AMF and NEF UE Context Registration Request/Response AMF, SMF, and SMSF Management DeregistrationNotification Subscribe/Notify (UECM) Deregistration Request/Response AMF, SMF, and SMSF Request/Response NEF, SMSF, GMLC, and NWDAF Update Request/Response AMF and SMF PCscfRestoration Subscribe/Notify AMF and SMF Request/Response Authentication ResultConfirmation Request/Response EventExposure Subscribe Subscribe/Notify NEF and NWD