Optical reroutable redundancy scheme

A method for a wavelength division multiplexing optical network employing an optical reroutable redundancy scheme and having optical crossconnects, the method comprising:

• maintaining in a database of an access node coupled to the wavelength division multiplexing optical network, organized by only the destination nodes of the available paths reachable from the access node to others of said access nodes, each such destination node having associated to it those of the available paths that lead to that destination node, each such available path having associated to it a path channel set that includes one or more wavelengths common to all of the interconnecting links of that path;
• selecting via a path selection module of the access node from said database ones of said available paths and unallocated wavelengths thereon;
• causing via a protection module coupled to said path selection module, responsive to failures affecting optical circuits, the provisioning of new optical circuits in real time and move the traffic to them,
• wherein in response to a failure of an optical circuit that was originated by the access node, the path selection module selects an alternative path and a wavelength of the selected alternative path from the database, wherein the protection module configures the wavelength of the alternative path with a destination node and zero and more intermediate nodes of the failed optical circuit and moves network traffic from the failed optical circuit onto the selected and configured wavelength of the alternative path,
• generating and transmitting via a start up module to adjacent nodes connectivity request messages to determine possible paths having said access node as a source node and meeting a set of zero or more connectivity constraints, and
• determining via a connectivity request module, responsive to each received connectivity request messages, any adjacent nodes to which the possible path that the connectivity request message has already collected can be extended to form additional possible paths having the originating access node as the source node and meeting the set of connectivity constraints, to transmit a message carrying that determination, and to propagate said connectivity request message to any adjacent nodes that may be able to determine additional possible paths having the originating access node as the source node and meeting the set of connectivity constraints,
• wherein each of the messages carrying a determination is transmitted back to the originating access node of the connectivity request message responsive to which that message was generated, and wherein each of said start up modules is also to build said database in its access node responsive to receiving the messages carrying determinations of additional possible paths having the access node as the source node and meeting the set of connectivity constraints.