A branch and price approach for optimal regenerator placement in translucent networks

In a translucent optical network, the optical signal is regenerated at selected nodes of the network, before the signal quality degrades below a threshold. Given the optical reach, to minimize the network cost, the goal of the regenerator placement problem is to find the minimum number of regenerators necessary in the network, so that every pair of nodes is able to establish a lightpath (either transparent or translucent) between them. In this paper, we have introduced a novel arc-chain formulation to compute the optimal number of regenerators needed for a translucent network. We have shown that our approach is considerably faster, particularly for large networks, than the node-arc formulation executed using commercially available optimization tools such as the CPLEX.