Patent ID: 7627243

Claim:
A method performed in an access node of a wavelength division multiplexing optical network, the method comprising: receiving a demand for allocating a protection path that meets a set of disjointness constraints with respect to a working path, the protection path suitable to be shared with one or more other working paths, each of the working paths associated with a priority for obtaining the shared protection path; and in response to the demand, selecting a protection path that meets the set of disjointness constraints with respect to the working path and has not been shared with another working path having the same priority as the working path associated with the protection path in demand, wherein the selected protection path is selected from a plurality of protection paths and wherein each of the protection paths is shared by a group of a plurality of working paths in a 1:N protection scheme, wherein each of the working paths in the group of plurality of working paths only use the selected protection path for protection, wherein each of the working paths within the group is associated with a different and unique priority, such that when multiple working paths sharing the same protection path fail simultaneously, a failed working path with a higher priority retains the shared protection path.