NUDM UECM

Information regarding the UEs current session is managed by the UECM service. The network functions that serve a UE register that information with the UDM, along with status information when appropriate and deregister after they are no longer serving that UE. A network function may also be notified that it has been deregistered when the UDM has determined that it is no longer the registered service provider for a particular UE. Additionally, this service is used by the AMF to update the UEs Permanent Equipment Identifier (PEI) and is used by the UDM to notify a registered AMF or SMF that P-CSCF restoration is required. Interested network functions can obtain context information on request to learn, for example, which AMF is currently serving a particular UE.