Charging in IP multimedia networks
IMS charging can be performed at various planes of the IMS architecture. Different charging schemes may be utilized. The optimal charging scheme would be service dependent, but may also be influenced by user expectations. The 3GPP has standardized charging mechanisms, protocols and interfaces for IMS charging control; online and offline charging have been standardized. However, the design and development of charging systems is operator dependent. This paper presents an IMS charging prototype developed and implemented in C, in line with Open IMS research. The testbed supports flow level, subsystem level and content level charging for IPTV and VoIP. The testbed supports online and offline charging; it has been tested with the UCT IMS client and the Fokus Open IMS system. Testbed proof of concept and performance results are presented.