23.2033GPPPolicy and charging control architectureRelease 17TS
The UDR is a functional entity that acts as a single logical repository storing user data. As such it may contain all subscriber/subscription related information needed by the PCRF. In deployment scenarios where the UDR is used it replaces the SPR. The UDR provides a unique reference point to fetch these subscriber/subscription data. This reference point is named Ud. More information on the UDR can be found in TS 23.335 .
The SPR data listed in clause 6.2.4 are stored in the UDR, the information model remains unspecified.