Subscriber Setup Overview
Before a subscriber’s data traffic can undergo TDF processing, a TDF subscriber session must be set up. The access network gateway — a broadband network gateway (BNG), gateway GPS support node (GGSN), or packet data network gateway (PGW) — must first identify the Service Control Gateway’s TDF address as a RADIUS server. When a potential TDF subscriber wants to access the TDF, the access network gateway sends a RADIUS accounting request to the TDF.
The Services Control Gateway examines the attribute-value pairs (AVP) of the RADIUS request, for example the 3GPP International Mobile Subscriber Identity (IMSI) or the IPv4 address of the subscriber, and determines whether a TDF subscriber session should be created and whether the session should be under dynamic or static control. These decisions are based on the subscriber’s attributes and on the way you configure the Services Control Gateway.
If the TDF subscriber session is under dynamic policy control, the Services Control Gateway also creates a session with the Policy and Charging Control Rules Function (PCRF). The PCRF correlates the TDF subscriber session with a wireless or wireline subscriber, and is then able to send appropriate Policy and Charging Control (PCC) rules to the Services Control Gateway. The PCRF uses Diameter to send messages to the Services Control Gateway.