Multi-objective routing wavelength assignment in WDM network using SPEA2 approach

Network design problem is usually complicated. Network designers may have to optimize various design objectives simultaneously. This paper considers a multi-objective network design problem for routing wavelength assignment (RWA) in WDM networks. The design objectives are to maximize the number of accepted communication requests (source-destination pairs) as well as to minimize the number of wavelength channel requirement subject to a limited number of wavelength channels available on each network link and at least 80% of all commodities must be accepted. Both the design objectives are conflicted to each other; maximizing the number of accepted commodities will require a large number of wavelength channels while minimizing the number of wavelength channels will limit the amount of accepted commodities. To solve the problem, we apply a famous multi-objective optimization approach called "SPEA2". The obtained results are compared with those from the Weighted Sum Approach in various weighted cases. The result comparisons show that the SPEA2 is superior in term of providing various sets of feasible solutions as a front in the objective space.