Optimizing Regenerator Cost in Traffic Grooming (Extended Abstract)

In optical networks regenerators have to be placed on lightpaths in order to regenerate the signal. In addition, grooming enables the use of the same regenerator by several lightpaths. In this work we consider the problem of minimizing the number of regenerators used in traffic grooming in optical networks. We deal with the case in which a regenerator has to be placed at every internal node of each lightpath. Up to g (the grooming factor) lightpaths can use the same regenerator. Starting from the 4-approximation algorithm of [7] that solves this problem for a path topology, we provide an approximation algorithm with the same approximation ratio for the ring and tree topologies. We present also a technique based on matching that leads to the same approximation ratio in tree topology and can be used to obtain approximation algorithms in other topologies. We provide an approximation algorithm for general topology that uses this technique.