US Patent 7764599 Network routing device and network routing method

A network routing device according to the invention transmits a packet via a second port based upon destination information included in the packet received via a first port referring to a routing table. In addition, the network routing device calculates beforehand a third port which is a transfer destination when a fault occurs in a destination connected to the second port. Further, the network routing device holds scenario information including a combination of the second port and the third port and updates the routing table based upon the scenario information when a fault is detected in either of the ports.