Regenerator site selection for mixed line rate optical networks

In this paper, we study the problem of regenerator site (RS) selection for mixed line rate optical networks (MLR-RSS), with the objective of minimizing the number of RSs for a given set of requests. We first provide the problem definition of MLR-RSS and show that the MLR-RSS problem is NP-complete. An integer linear programming model is formulated. We then present two heuristic algorithms, named the independent algorithm and the sequential algorithm, and two approximation algorithms, named the MLR-combined algorithm and the weighted MLR-combined algorithm. The performance of the algorithms is compared via simulation, and results show that the weighted MLR-combined algorithm has the best performance. Results suggest that our proposed MLR algorithm outperforms existing single line rate algorithms by more than 20%. Also, the RS distribution suggests that certain nodes in the network have a much higher probability of being chosen as RSs than the others.