Charging Trigger Function (CTF) in Mobile Network

Charging Trigger Function (CTF) is responsible for detecting and monitoring user activities and charging events. As example, voice calls, data sessions, and SMS.

When a chargeable event occurs, the CTF collects relevant information about the event, such as the subscriber's identity, location, duration, volume, and other parameters.

Then the CTF sends those charging events to the CDF via Rf reference point, in order to charge the end user.

The CTF exists in network elements that generate charging records for the users such as the GGSN, the SGW, and the PGW.