On Optimal<tex>$p$</tex>-Cycle-Based Protection in WDM Optical Networks With Sparse-Partial Wavelength Conversion

Abstract

We study the optimal configuration of p-cycles in survivable wavelength division multiplexing (WDM) optical mesh networks with sparse-partial wavelength conversion while 100% restorability is guaranteed against any single failures. We formulate the problem as two integer linear programs (Optimization Models I, and II) which have the same constraints, but different objective functions. p-cycles and wavelength converters are optimally determined subject to the constraint that only a given number of nodes have wavelength conversion capability, and the maximum number of wavelength converters that can be placed at such nodes is limited. Optimization Model I has a composite sequential objective function that first (G1) minimizes the cost of link capacity used by all p-cycles in order to accommodate a set of traffic demands; and then (G2) minimizes the total number of wavelength converters used in the entire network. In Optimization Model II, the cost of one wavelength converter is measured as the cost of a deployed wavelength link with a length of alpha units; and the objective is to minimize the total cost of link capacity & wavelength converters required by p-cycle configuration. During p-cycle configuration, our schemes fully takes into account wavelength converter sharing, which reduces the number of converters required while attaining a satisfactory level of performance. Our simulation results indicate that the proposed schemes significantly outperform existing approaches in terms of protection cost, number of wavelength conversion sites, and number of wavelength converters needed