Gy Interface

The Gy interface is the Online Charging interface between the SMF Charging Trigger Function (CTF) and the Online Charging System (OCS) Charging-Data-Function (CDF). This interface is based on the 3GPP standards and relies on quota allocation. The OCS is the Diameter Credit Control server, which provides the online Charging data to the SMF. With the Gy interface, customer traffic is gated and billed in an online or prepaid style. SMF supports both the time-based and volume-based charging models.