Availability models for protection techniques in WDM networks

This paper deals with the most common protection schemes in WDM optical networks, providing for each of them an algebraic formulation of availability analysis. We consider single or multiple link failure scenarios, being a link failure a fault that affects all the optical connections routed on the involved link. Availability models are applied to some numerical examples that allow us to compare the different availability degrees granted by each protection technique. When an approximation is introduced in the presented formulas, Monte-Carlo-approach simulation results are given to verify the accuracy of the theoretical analysis. The paper highlights some important availability relations between path-protection schemes and most relevant network parameters.