Patent ID: 7639615

Claim:
A method of determining an alternative communication path in a communication network built with a plurality of network nodes, comprising: assuming that a network failure occurs at a location in a current communication path, the current communication path being a single path connecting a plurality of path network nodes in a row, the path network nodes being nodes included in the network nodes, the path network nodes being divided into first path network nodes and second path network nodes, the first path network nodes being nodes that are located on upper stream of the current communication path from the location of the network failure, and the second path network nodes being nodes that are located on down stream of the current communication path from the location of the network failure; determining a failure detected network node that detects the network failure, out of the path network nodes; calculating a failure notification time for each network node, the failure notification time indicating a time from when a failure notification message is transmitted by the failure detected network node until the each network node receives the failure notification message; selecting a first network node based on the failure notification time, out of the first path network nodes that are positioned in the current communication path on the upper stream from the location of the network failure; and determining an alternative communication path that includes the first network node and a second network node out of the second path network nodes with a network node having the failure notification time longer than the failure notification time of the first network node excluded from network nodes forming the alternative communication path, the second network node being positioned in the current communication path on the down stream from the location of the network failure.