Patent ID: 7499646
Filing Date: 2009-03-03
Classification: H04J,H04Q

Abstract:
1. A method performed by a node of a wavelength multiplex optical network, the method comprising: detecting at the node that at least a portion of functionality of a wavelength of a first unidirectional path (first path/wavelength) of an optical circuit fails to operate, the first unidirectional path being originated from a first terminating node as a source node for reaching a second terminating node as a destination node of the first unidirectional path, the first terminating node and the second terminating node forming the optical circuit, wherein the optical circuit includes a non-terminating node; determining within the node whether the node is the second terminating node of the optical circuit in response to detecting a failure of the first unidirectional path; if it is determined that the node is the second terminating node of the optical circuit, the node signaling the first terminating node by removing a light of a second wavelength of a second unidirectional path (second path/wavelength) in an opposite direction of the first unidirectional path of the optical circuit, to indicate the failure of the first path/wavelength, wherein in response to lost of the at least a portion of light, which is used as an indication of lost of signal (LOS), the first terminating node is configured to provision another path to reach the second terminating node as the same destination of the first unidirectional path, bypassing at least one node between the first terminating node and the second terminating node of the first unidirectional path; and the node ignoring the failure of the first unidirectional path without removing the light of the second wavelength of the second unidirectional path if it is determined that the node is not the second terminating node of the optical circuit.