What the UDM does
The UDM supports management of subscriber identity and subscription-related information. It exposes services used during authentication, registration and session establishment.
Slice subscriptions
Subscription information can include the S-NSSAIs a subscriber is authorised to use. The serving network uses this as part of the decision about allowed slices.
UDM and UDR
The UDM provides application logic around subscriber data, while a UDR can provide structured data storage used by several network functions.
Standards note: this page is an explanatory summary. Precise procedures, services and information elements are defined in the applicable 3GPP specifications.