Enhanced routing and wavelength assignment techniques for reducing wavelength continuity blocking

1. A method for optimizing routing and wavelength assignment in a network, the method comprising:

determining, by a source node in the network, a routing assignment for the network, wherein the routing assignment is determined using a decongestion cost-based function;

determining, by the source node, a wavelength assignment for the network based on a vector difference, wherein the vector difference uses bit operations to describe wavelength usage across links in the network based on how the links are connected, the determination of the wavelength assignment comprising

spanning the network for a path,

calculating a weighted correlation function for at least one length in the network,

storing the weighted correlation,

determining if a next path exists,

if the next path is found, spanning for the next path in the network, and

if the next path is not found, returning the stored correlation, and wherein the cost-based function comprises assigning a connectivity weight to each cross connect within the source node, determining a runtime hop count during route computation, and calculating an incremental and cumulative cost based route on the connectivity weight and the hop count.

2. The method of claim 1 , further comprising determining at least one path for routing based on the cost-based function.

3. The method of claim 2 , wherein a set of shortest length paths comprises at least one shortest length path that is longer than a second shortest length path in the set of shortest length paths.

4. The method of claim 1 , further comprising:

calculating at least one vector difference in a spanning process for a wavelength vector in the network for a lightpath reservation based on wavelength continuity to avoid blocking due to node or network segmentation as part of lightpath reservations.

5. The method of claim 4 , further comprising:

determining a wavelength based in part on stored calculated vector differences.

6. The method of claim 1 , further comprising computing minimum spanning tree (MST) links for networks with more than 20 nodes.

7. The method of claim 1 , further comprising calculating wavelength vectors for links within two level proximity for a current working path.

8. The method of claim 1 , further comprising using integer linear programming.

9. The method of claim 1 , wherein the network comprises a heterogeneous bandwidth composition.

10. The method of claim 1 , further comprising assigning a weight with each new path found.

11. An apparatus, in a source node in a network, for optimizing routing and wavelength assignment in the network, comprising:

logic configured to determine a routing assignment for a network, wherein the routing assignment is determined using a decongestion cost-based function;

logic configured to determine a wavelength assignment for the network based on a vector difference, wherein the vector difference uses bit operations to describe wavelength usage across links in the network based on how the links are connected, the determination of the wavelength assignment comprising

logic configured to span the network for a path,

logic configured to calculate a weighted correlation function for at least one length in the network,

logic configured to store the weighted correlation,

logic for determining if a next path exists,

logic configured to span for the next path in the network if the next path is found, and

logic configured to return the stored correlation if the next path is not found, and

wherein the cost-based function is implemented through logic configured to assign a connectivity weight to each cross connect within the source node, logic configured to determine a runtime hop count during route computation, and logic configured to calculate an incremental and cumulative cost based route on the connectivity weight and the hop count.

12. The apparatus of claim 11 , further comprising:

logic configured to determine at least one path for routing based on the cost-based function.

13. The apparatus of claim 12 , wherein a set of shortest length paths comprises at least one shortest length path that is longer than a second shortest length path in the set of shortest length paths.

14. The apparatus of claim 11 , further comprising:

logic configured to calculate at least one vector difference for a second wavelength in the network for a lightpath reservation based on wavelength continuity to avoid blocking due to node or network segmentation as part of lightpath reservations.

15. The apparatus of claim 14 , further comprising:

logic configured to determine a path based on stored calculated vector differences.

16. The apparatus of claim 11 , further comprising logic configured to compute minimum spanning tree (MST) links for networks with more than 20 nodes.

17. The apparatus of claim 11 , further comprising logic configured to calculate wavelength vectors for wavelengths within two level proximity for a current working path.

18. The apparatus of claim 11 , further comprising logic configured to use integer linear programming.

19. The apparatus of claim 11 , wherein the network comprises a heterogeneous bandwidth composition.

20. The apparatus of claim 11 , further comprising logic configured to assign a weight with each new path found.

21. A network with an apparatus for optimizing routing and wavelength assignment in the network, comprising:

a plurality of nodes interconnected to one another through a plurality of wavelengths; and

a processor at a source node of the plurality of nodes configured to

determine a routing assignment for a network, wherein the routing assignment is determined using a decongestion cost-based function,

determine a wavelength assignment for the network based on a vector difference, wherein the vector difference uses bit operations to describe wavelength usage across links in the network based on how the links are connected, and wherein for the determination of the wavelength assignment, the processor is configured to

span the network for a path,

calculate a weighted correlation function for at least one length in the network,

store the weighted correlation,

determine if a next path exists,

span for the next path in the network if the next path is found, and

return the stored correlation if the next path is not found, and

wherein, for the cost-based function, the processor is further configured to assign a connectivity weight to each cross connect within the source node, determine a runtime hop count during route computation, and calculate an incremental and cumulative cost based route on the connectivity weight and the hop count.

22. The network of claim 21 , wherein the processor is further configured to

determine at least one path for routing based on the cost-based function.

23. The network of claim 22 , wherein a set of shortest length paths comprises at least one shortest length path that is longer than a second shortest length path in the set of shortest length paths.

24. The network of claim 21 , wherein the processor is further configured to

calculate at least one vector difference for a second wavelength in the network for a lightpath reservation based on wavelength continuity to avoid blocking due to node or network segmentation as part of lightpath reservations.

25. The network of claim 24 , wherein the processor is further configured to

determine a path based on stored calculated vector differences.

26. The apparatus of claim 21 , wherein the processor is further configured to calculate wavelength vectors for wavelengths within two level proximity for a current working path.

27. The apparatus of claim 21 , wherein the processor is further configured to assign a weight with each new path found.

28. The apparatus of claim 21 , wherein the processor is further configured to assign a weight with each new path found.

29. Software for optimizing routing and wavelength assignment in a network stored in a non-transitory computer-readable medium, comprising:

at least one instruction executed by one or more processors at a source node in a network to determine a routing assignment for the network, wherein the routing assignment is determined using a decongestion cost-based function;

at least one instruction executed by the one or more processors at the source node to determine a wavelength assignment for the network based on a vector difference, wherein the vector difference uses bit operations to describe wavelength usage across links in the network based on how the links are connected, the determination of the wavelength assignment comprising

at least one instruction executed by the one or more processors to span the network for a path,

at least one instruction executed by the one or more processors to calculate a weighted correlation function for at least one length in the network,

at least one instruction executed by the one or more processors to store the weighted correlation,

at least one instruction executed by the one or more processors to determine if a next path exists,

at least one instruction executed by the one or more processors to span for the next path in the network if the next path is found, and

at least one instruction executed by the one or more processors to return the stored correlation if the next path is not found, and

wherein the cost-based function is implemented through at least one instruction executed by the one or more processors to assign a connectivity weight to each cross connect within the source node, at least one instruction executed by the one or more processors to determine a runtime hop count during route computation, and at least one instruction executed by the one or more processors to calculate an incremental and cumulative cost based route on the connectivity weight and the hop count.