Section: 6.2.7 UDM
Content: The Unified Data Management (UDM) includes support for the following functionality: - Generation of 3GPP AKA Authentication Credentials. - User Identification Handling (e.g. storage and management of SUPI for each subscriber in the 5G system). - Support of de-concealment of privacy-protected subscription identifier (SUCI). - Access authorization based on subscription data (e.g. roaming restrictions). - UE's Serving NF Registration Management (e.g. storing serving AMF for UE, storing serving SMF for UE's PDU Session). - Support to service/session continuity e.g. by keeping SMF/DNN assignment of ongoing sessions. - MT-SMS delivery support. - Lawful Intercept Functionality (especially in outbound roaming case where UDM is the only point of contact for LI). - Subscription management. - SMS management. - 5G-VN group management handling. - Support of external parameter provisioning (Expected UE Behaviour parameters or Network Configuration parameters). - Support for the Disaster Roaming as described in clause 5.40. - Support for the control of time synchronization service based on subscription data as described in clause 5.27.1.11. To provide this functionality, the UDM uses subscription data (including authentication data) that may be stored in UDR, in which case a UDM implements the application logic and does not require an internal user data storage and then several different UDMs may serve the same user in different transactions. NOTE 1: The interaction between UDM and HSS, when they are deployed as separate network functions, is defined in TS 23.632[ User data interworking, coexistence and migration; Stage 2 ]  [102] and TS 29.563[ 5G System; Home Subscriber Server (HSS) services for interworking with Unified Data Management (UDM); Stage 3 ]  [103] or it is implementation specific. NOTE 2: The UDM is located in the HPLMN of the subscribers it serves, and access the information of the UDR located in the same PLMN.