Least cost call routing-a brilliant application for private IN

'Least cost call routing' (LCCR) is a facility in private telecommunication networks (PTNs) used to cut the operating costs by selecting the cheapest routes for external calls. Private network operator demand for LCCR features is growing. This demand will be strengthened by deregulation as, for example, in Europe. Conventional LCCR facilities are implemented as an additional routing feature being part of the switch software. These LCCR realizations suffer from several handicaps. Our solution is based on the IN paradigm to get complex services out of the switch. We have realized a prototype LCCR server as a service control function (SCF) running on an external PC. This approach also allows to overcome limitations concerning LCCR data handling by providing a flexible service data function (SDF). Finally, a service management function (SMF) allows to fully exploit the LCCR capabilities by maintaining a global view on the PTN resources and relevant public tariffs for the calculation of the local LCCR data.