Interaction Between an Online Charging System and a Policy Server
According to the 3GPP standard architecture up to Release 9, a Charging System is not supposed to interact directly with a Policy Server. The Charging System is responsible for rating and charging, while the Policy Server is responsible for determining the right policy depending on the kind of traffic. In reality, it appears that the decision about the right policy might be influenced by some real-time subscriber information, which might also be relevant for charging, and therefore stored in the Charging System. In this context, a direct interface between the Charging System and the Policy Server might be required.