Optimization model for the design of WDM networks with fuzzy costs

The fluctuations that have taken place in the worldwide economy in the last years make it difficult to estimate the costs of the equipments that have to be used in order to design a telecommunications network. The literature is replete with prescriptive integer programming models for various versions of network design problems, but in no case they consider the real situation of solving them taking into account their inherent vagueness due to the equipment costs. This paper considers the real-world wavelength division multiplexing (WDM) network design problem. The vagueness that appears in this problem is assumed and handled by means of fuzzy sets based methodologies. A fuzzy integer linear programming model is then proposed to be used as an auxiliary model for solving the former problem. With the purpose of obtaining cost-effective network designs, this model is then solved using Cplex, which is a commercial high performance optimization engine.