Patent ID: 8619551

Claim:
A protection path reservation method which reserves protection paths to avoid a node failure for each optical transmission path on an all-optical network formed of a plurality of nodes, the method comprising: assuming, by a protection path reservation processing unit, each of the nodes in turn as an imaginary failure node in a condition in which the node failure is not present in the all-optical network; and selecting, by the protection path reservation processing unit, N neighbor nodes connected to the imaginary failure node through N links; wherein the all-optical network transparently transmits an optical signal without converting the optical signal into an electrical signal at a node and also without converting a wavelength of the optical signal; wherein the imaginary failure node sequentially transmits protection path reservation request messages to only the N neighbor nodes of the imaginary failure node; and each of the N neighbor nodes which has received the protection path reservation request messages sequentially, one by one, reserves Nâˆ’1 protection paths starting from the nodes in descending order of length.