ETSI TS 123 335 describes the procedures and signalling flows associated to the technical realization of the 3GPP User Data Convergence (UDC). It furthermore indicates some requirements for the stage 3 specifications.

Special consideration is put in the following areas:

• reference architecture for the UDC concept
• general description of procedures for the user data manipulation (e.g. create, delete, update, etc.)
• identification of the requirements on the UDC for the applicability of the mechanisms described in this document.

User data convergence is an optional concept to ensure data consistency and simplify creation of new services by providing easy access to the user data, as well as to ensure the consistency of storage and data models and to have minimum impact on traffic mechanisms, reference points and protocols of network elements.

Standization of the Data Model for the Ud interface between Front-Ends and the UDR is out of the scope of 3GPP.