Abstract: For a connection-oriented network system in which information terminals such as PC and WS are connected to a network such as LAN and WAN and a logical connection is established if necessary to a terminal to transfer data over the established connection, a service management method is provided which allows data transfer without connection management by a service application. A communication driver for data transfer is provided with a connection processing unit for establishing a connection to a transmission destination terminal and a connection queue for temporarily storing transmission data during a connection process.

Abstract: A method and system for entering the address of an address server to plural terminals connected to a switch, selecting a target address and switching to a substitute address server when a failure occurs in the target address server. In the invention when the switch is activated, its address management section generates a logical network table. Next when each terminal is activated, its address processing section generates a server address table and informs the switch of the address and the logical network of the terminal and whether the terminal is an address server. The address management section of the switch registers this information to logical network table. When another terminal is activated and informs the switch of its address and logical network, the address management section of the switch registers the information to its logical network table, and checks whether the address server of the other terminal has been registered.