Patent ID: 6894971

Claim:
A redundant structure control device for use with an exchange having a Asynchronous Transfer Mode (ATM) switch, an ATM concentrator, a plurality (N+1) of line interface devices to interface with a plurality (N+1) of ATM lines, the (N+1)th line interface device being a spare line interface device, the (N+1th) ATM line being a spare ATM line the redundant structure control device comprising: frame tag attaching means, disposed between the ATM lines and the line interface devices, for attaching a routing header containing tag information to each frame coming from the ATM lines or line interface devices; frame switching means, coupled to said frame tag attaching means, for switching frames between the ATM lines and the line interface devices in accordance with said tag information given to each frame; tag changing means, disposed in the ATM concentrator, for changing tag values of ATM cells sent from the ATM switch, the tag values indicating to which line interface devices the ATM cells are addressed; and routing control means for setting up said frame tag attaching means and said tag changing means; wherein, in response to troubles with the I-th ATM line and with the j-th line interface device where neither (nor j is equal to (N+1), said routing control means sets up said frame tag attaching means and tag changing means such that; frames coming from and going to the (N+1)th ATM line be supplied to and from the j-th line interface device, frames coming from and going to the j-th ATM line be supplied to and from the (N+1)th line interface device, and ATM cells addressed from the ATM switch to the j-th line interface device be redirected to the (N+1)th line interface device.