Difference between CTF and CDF ?

Question

I want to know about Charging Trigger Function and Charging Data Function in details.

Comments

You will get the answer in details in below link:
http://www.lteandbeyond.com/2012/01/offline-charging-system-ofcs.html

Answer 1

CTF - Charging Trigger Function is part of the service element, responsible for monitoring service usage and generating charging events based on it.
CDF - Charging Data Function is responsible for generating CDRs (charging data records), based on events received from the CTF, and transferring them to the Charging Gateway Function.
CGF - Charging Gateway Function is responsible for persistent storage of the CDRs and some processing and error checking; it also collects CDRs from many Charging Data Functions and sends them to the billing system.

Answer 2

The Charging Trigger Function i.e. CTF generates charging events based on the observation of network resource usage. In every network and service element that provides charging information, the CTF is the focal point for collecting the information pertaining to chargeable events within the network element, assembling this information into matching charging events, and sending these charging events towards the Charging Data Function. The CTF is a mandatory, integrated component in all network elements that provide offline charging functionality.

Charging Data Function i.e. CDF receives charging events from the Charging Trigger Function via the Rf reference point. It then uses the information contained in the charging events to construct CDRs.

Reference: 3GPP 32240.XX