Regeneration Sites Identification in Translucent Elastic Optical Networks

In a Translucent Elastic Optical Network, an optical signal can be propagated beyond its transparent reach by 3R regeneration (re-shaping, re-timing and re-timing) at certain nodes identified as regeneration sites. These regeneration sites increase network deployment cost and 3R regeneration of optical signals increases operational costs. So it is desired that optical signals undergoes 3R regeneration as sparingly as possible. This leads to the regeneration sites identification (RSI) problem, an NP-Complete problem. The goal of the RSI problem is to determine the minimum number of regeneration sites at which an optical signal needs to undergo 3R regeneration so that communication between all node pairs in the network can be established. In this paper, we present an Integer Linear Program (ILP) formulation for the problem for small networks and also propose a polynomial time heuristic algorithm ERSI (Efficient Regeneration Sites Identification) for large networks. Simulation results show that our heuristic provides near optimal results and outperforms known heuristics.