Abstract: The invention relates to a method and data structure for controlling switching centers (1, 14, 17, 19, 21, 23, 25, 27) connected to each other by a telecommunications network. The switching centers are provided with semipermanent databases containing alterable network control information related to, inter alia, call charging and routing. The information stays constant unless separately altered by an external control. Terminals (3) such as PABX connections, conventional subscriber lines, telefax equipment etc., are connected by a telecommunications network to the switching centers, and at least one service database (5) is common to the network and contains at least a portion of the network control information. According to the invention, the switching centers are controlled to update the control information stored in the semipermanent databases with information retrieved from the service database (5).