This TS provides the stage 3 specification of the Sy
reference point for the present release. The functional requirements and the stage 2 specifications of the Sy reference point are contained in TS 23.203
The Sy reference point lies between the Policy and Charging Rule Function (PCRF) and the Online Charging System (OCS).
The internal OCS functionality for policy counter provision management pertaining to Sy is specified in TS 32.296