Model IDs Optimal Paths in Fiber Optic Networks

Fiber optic network designers need to find the most efficient way to connect distant phones and computers — a costly and time-consuming process. Now researchers have a model that they say finds optimal connections 10,000 times more quickly, while using less computing power to solve the problem.

“Problems that used to take days to solve can now be solved in just a few seconds,” said George Rouskas, computer science professor at North Carolina State University and the author of a paper describing the new method. The model could solve problems much faster when data is routed through larger “rings” in the network, he said.

The researchers have designed a mathematical model that identifies the exact optimal routes and wavelengths for ring network designers. The model creates a large graph of all the paths in a ring, and where those paths overlap. It then breaks that graph into smaller units, with each unit consisting of the paths in a ring that do not overlap. Because these paths do not overlap, they can use the same wavelengths of light, whereas paths that overlap cannot use the same wavelengths.

By breaking all of the potential paths down into these smaller groups, the model is able to identify the optimal path and wavelength between two points much more efficiently than previous techniques.

“This will significantly shorten the cycle of feedback and redesign for existing rings,” Rouskas said. “It also means that the ring design work can be done using fewer computer resources, which makes it less expensive. This should allow network providers to be more responsive to user demands than ever before.”

The research paper, “Fast Exact ILP Decompositions for Ring RWA,” is published in the July 2011 issue of the Journal of Optical Communications and Networking. The paper was authored also by Emre Yetginer and Zeyu Liu. The research was conducted at North Carolina State University.

For more information, visit: www.ncsu.edu