ese numbers are to be routed to one physical telephone number depending on where the call is initiated or time of day. As more and more of these kinds of services have been introduced, the updating of new serv- ices to many exchanges has become a great burden to the network operator. The IN structure was developed to help network operators and service provid- ers introduce, update, and develop new services in a more efficient way. 2.10.4.2 Centralized Intelligence The basic structure of an IN, illustrated in Figure 2.19, is based on central- ized intelligence. With central intelligence, control information is stored in a central place and the same information is available for all exchanges in the network. Exchanges request information when they need it for call handling. The great advantage of the IN concept is that when a new service is The Telecommunications Network: An Overview The structure of intelligent network SMS: service management center, for the updating of services or the introduction of new ones SCP: service control point, which gives routing and charging information to switches DB: database, stores the service information, for example, number conversion for call transfer SSP: service switching point, telephone exhange which requests routing information from SCP if IN-number is detected Server for IP: intelligent peripheral, gives the voice value-added notifications if required services Figure 2.19 The structure of the IN. introduced or a service is updated, all exchanges in the network are able to provide the modified service immediately. 2.10.4.3 Structure of the IN IN technology makes provision of new services efficient with the help of con- trol data that are centralized and available to all switches. Otherwise, service information would need to be updated to all exchanges when a change is made. Figure 2.19 shows the main network elements of an IN. The service management system (SMS) provides tools for introduction of new services and service updates. The database (DB) contains control informatio