Photonic routing systems and methods computing loop-free topologies

1. A method for routing wavelengths in an optical network, the method comprising:

responsive to a path request for a wavelength or group of wavelengths, determining a path through the optical network;

determining a location on the path where wavelength blocking should occur to form a loop-free path in the optical network; and

setting the wavelength blocking at the location.

2. The method of claim 1 , wherein the optical network utilizes a broadcast and select architecture and the wavelength blocking is configured to prevent the wavelength or group of wavelengths from looping back on a port where the wavelength or group of wavelengths has already been received on.

3. The method of claim 1 , wherein the optical network utilizes an all-broadcast architecture and the wavelength blocking is configured to prevent multiple paths for the wavelength or group of wavelengths by constraining the wavelength or group of wavelengths to a single path through the optical network.

4. The method of claim 1 , wherein the determining a location on the path where wavelength blocking should occur utilizes a spanning tree in the optical network from any node in the optical network to a root node, and wherein the wavelength blocking is based on the spanning tree.

5. The method of claim 1 , wherein the determining a location on the path where wavelength blocking should occur utilizes a shortest path tree in the optical network from any node in the optical network to a root node, and wherein the wavelength blocking is based on the shortest path tree.

6. The method of claim 1 , wherein the determining a location on the path where wavelength blocking should occur utilizes Ethernet Ring Protection Switching as a control protocol.

7. The method of claim 1 , wherein the determining a location on the path where wavelength blocking should occur utilizes an optical routing protocol associated with the optical network.

8. The method of claim 1 , wherein the determining a location on the path where wavelength blocking should occur utilizes link state protocols and associated link state messages to determine the wavelength blocking.

9. A system for routing wavelengths in an optical network, the system comprising:

a processor communicatively coupled to the optical network; and

memory storing instructions that, when executed, cause the processor to

responsive to a path request for a wavelength or group of wavelengths, determine a path through the optical network,

determine a location on the path where wavelength blocking should occur to form a loop-free path in the optical network, and

cause the wavelength blocking at the location.

10. The system of claim 9 , wherein the optical network utilizes a broadcast and select architecture and the wavelength blocking is configured to prevent the wavelength or group of wavelengths from looping back on a port where the wavelength or group of wavelengths has already been received on.

11. The system of claim 9 , wherein the optical network utilizes an all-broadcast architecture and the wavelength blocking is configured to prevent multiple paths for the wavelength or group of wavelengths by constraining the wavelength or group of wavelengths to a single path through the optical network.

12. The system of claim 9 , wherein the determining a location on the path where wavelength blocking should occur utilizes a spanning tree in the optical network from any node in the optical network to a root node, and wherein the wavelength blocking is based on the spanning tree.

13. The system of claim 9 , wherein the determining a location on the path where wavelength blocking should occur utilizes a shortest path tree in the optical network from any node in the optical network to a root node, and wherein the wavelength blocking is based on the shortest path tree.

14. The system of claim 9 , wherein the determining a location on the path where wavelength blocking should occur utilizes Ethernet Ring Protection Switching as a control protocol.

15. The system of claim 9 , wherein the determining a location on the path where wavelength blocking should occur utilizes an optical routing protocol associated with the optical network.

16. The system of claim 9 , wherein the determining a location on the path where wavelength blocking should occur utilizes link state protocols and associated link state messages to determine the wavelength blocking.

17. The system of claim 9 , wherein the system is a Path Computation Element.

18. A node in an optical network, comprising:

a plurality of degrees connected to the optical network;

optical devices configured to broadcast a plurality of wavelengths through the plurality of degrees;

selectively enabled blocking elements at the plurality of degrees; and

a processor configured to selectively enable a blocking element responsive to a loop-free path computed in a network in which node participates, based on a routing protocol which computes the loop-free path for at least one wavelength of the plurality of wavelengths.

19. The node of claim 18 , wherein the optical network utilizes a broadcast and select architecture and the blocking element is configured to prevent the at least one wavelength from looping back on a port where the at least one wavelength has already been received on.

20. The node of claim 18 , wherein the optical network utilizes an all-broadcast architecture and the blocking element is configured to prevent multiple paths for at least one wavelength by constraining the at least one wavelength to a single path through the optical network.