Capacity expansion of fiber optic networks with WDM systems: problem formulation and comparative analysis

Abstract

In this paper we provide an arc-path formulation for the problem of locating and sizing wavelength division multiplexing (WDM) and optical cross-connect (OXC) equipment in a fiber optic network. The problem is heuristically solved by limiting the number of paths for each demand and applying CPLEX to the resulting formulation. The results obtained are then compared to those given by a metaheuristic method previously developed for this problem. A set of real and randomly generated instances with different characteristics associated with actual telecommunication networks are used to assess the performance of both solution approaches. Scope and purpose The problem that we address in this paper deals with the effective utilization of new technology designed to increase the capacity of a fiber optic telecommunication network. The problem arises when the demand for bandwidth in a fiber optic network exceeds the current capacity. The new technology, wavelength division multiplexing (WDM), can expand the capacity of a fiber optic network without requiring additional fiber. The decision problem is to find the most cost-effective combination of WDM equipment and fiber that increases the capacity of the network to a point where all the expected demand can be handled. The purpose of our paper is to introduce a new mathematical formulation for this combinatorial optimization problem that we use in two different ways: (1) finding heuristic solutions to the problem and (2) assessing the quality of the solutions found with a metaheuristic procedure. We test our approach with real data from metro area and long haul networks. The computational tests show that the proposed metaheuristic is capable of finding near-optimal solutions to this difficult problem.