Patent ID: 8908502

Claim:
A communication system comprising a plurality of node devices, wherein each of said plurality of node devices comprises a controller configured to: detect a failure on a first transmission path over which data transmission is being performed; when said failure exists in a link or a node that is located immediately before its own node, set a single second transmission path as far as a transmission terminal node, said second transmission path that excludes a path from said transmission terminal node to a node that has detected said failure within said first transmission path; transmit a first failure notification signal as far as said transmission terminal node over said second transmission path; upon receipt of said first failure notification signal, switch a switch instantly for data transmission so that a path for new data transmission is the same path as a transmission path for said first failure notification signal; and upon said transmission terminal node receiving said first failure notification signal, switch said switch to said second transmission path and perform a new data transmission over said second transmission path, wherein when said second transmission path overlaps with part of said first transmission path, transmit a second failure notification signal, different from the first notification signal, to one or more nodes located downstream of said first transmission path, and upon receipt of said second failure notification signal at a junction node where overlapping between the first transmission path and the second transmission ends, transmit said first failure notification signal from the junction node over said second transmission path.