Although it represents a totally different business case, this type of billing uses the same internal architecture of number translation plug-ins, described in the previous section. The only difference is that, in this case, the dialed number is checked against a list of “favorite” numbers defined for each account. If a match is found, the call is rated according to a special rate for the FAV destination, defined in the customer’s tariff. This allows you to offer customers a “call friends & family cheaper”-type service.
In a premium number billing model, PortaBilling investigates (either in a local database or an external one) to determine a number’s routing destination and which rating code must be used for charging your customer.