The process starts when the softswitch receives the incoming call from the originating gateway or SIP endpoint. The switch then identifies the caller’s Account (1). The start of the process is called Authentication. If the Account cannot be identified the call is rejected. Once the Account has been identified the switch enumerates all Customers that need to be charged for the call (2). For each Account and Customer in the list, the switch then locates the associated Tariff and Rate; it then calculates the maximum duration for the call (3) based on the number called. If at least one Rate cannot be found or if the balance of the Account or Customer is not sufficient the call is rejected.
The next step is Routing – based on the number called and routing configuration assigned to the Account or Customer the switch enumerates one or more Connections for terminating the call to (4). Based on that information the switch performs actual overflow routing (5) until the call is either connected or there are no more connections to try.
Once the call has been completed, either successfully or unsuccessfully the switch charges Account, Customer(s) and Vendor associated with the call and creates the appropriate CDRs (6).