UDM

Technical Explanation

The UDM is the 5G evolution of the 4G HSS (Home Subscriber Server). It manages subscriber data, generates 5G-AKA authentication vectors (in conjunction with the ARPF / Authentication Credential Repository and Processing Function), handles subscription identification de-concealing (resolving SUCI to SUPI via SIDF), processes SMS management, and manages roaming authorization. UDM is stateless, storing all subscription data in the Unified Data Repository (UDR).

Key Functions

• Management of user subscription profiles and authorized slices
• Generation of 3GPP 5G authentication credentials and vectors
• De-concealment of encrypted SUCI into SUPI (via embedded SIDF)
• Access authorization, serving NF registration, and SMS management