Section: 4.1.2 Online charging
Content: Online charging is a process where charging information for network resource usage is collected concurrently with that resource usage in the same fashion as in offline charging. However, authorization for the network resource usage must be obtained by the network prior to the actual resource usage to occur. This authorization is granted by the OCS or CCS upon request from the network. When receiving a network resource usage request, the network assembles the relevant charging information and generates a charging event towards the OCS or CCS in real-time. The OCS or CCS then returns an appropriate resource usage authorization. The resource usage authorization may be limited in its scope (e.g. volume of data or duration), therefore the authorization may have to be renewed from time to time as long as the user’s network resource usage persists. Note that the charging information utilized in online charging is not necessarily identical to the charging information employed in offline charging. In conclusion, online charging is a mechanism where charging information can affect, in real-time, the service rendered and therefore a direct interaction of the charging mechanism with the control of network resource usage is required.