Abstract: A service interruption time is shortened in redundancy switching, thereby to render a vocal service of good quality, in addition to a data service of good quality by a server. In case of redundancy switching, an IP filter is set in a standby system server, and the standby system server is given the same IP address as an IP address given to an operation system server and is thereafter shifted into an operating state. On the other hand, the original operation system server deletes the given IP address and is thereafter shifted from an operating state into a standby state. The original standby system server releases the set IP filter, and thereafter starts the provision of a service.

Abstract: A service interruption time is shortened in redundancy switching, thereby to render a vocal service of good quality, in addition to a data service of good quality by a server. In case of redundancy switching, an IP filter is set in a standby system server, and the standby system server is given the same IP address as an IP address given to an operation system server and is thereafter shifted into an operating state. On the other hand, the original operation system server deletes the given IP address and is thereafter shifted from an operating state into a standby state. The original standby system server releases the set IP filter, and thereafter starts the provision of a service.

Abstract: In an ATM switching network, a limitation of traffic in an ATM switching apparatus is relaxed. In an ATM switching network capable of allocating a plurality of communication channels to a terminal unit of one subscriber, when the terminal of this subscriber requests setting of the plural communication channels, a traffic amount of the communication channels proposed to the ATM switching apparatus is declared as a total amount of the respective communication channels. The ATM switching apparatus measures a total traffic amount of the plural communication channels set in response to the request made by the terminal unit, and limits the traffic of the plural set communication channels in such a manner that the measured traffic amount becomes lower than, or equal to the traffic amount declared through the terminal unit.