Highly reliable and available systems in all-optical networks require the implementation of various types of redundancy. For reliability and availability analysis systems can be described by reliability block diagrams or diagrams describing system state transitions. Analytical calculations for characteristic reliability and availability parameters such as mean time to failure or average availability for complex, repairable systems containing redundancies rapidly become costly and intractable. Monte Carlo simulation and Markov process calculations are therefore deployed. Results of simulations and calculations show sufficient accuracy and high flexibility for sensitivity analysis. Sensitivity analysis is the quantitative identification of system parts dominating the overall system availability by systematical variation of calculation input data, i.e. failure and repair rates. This gives valuable input for possible system optimization comprising technical and economical aspects. This contribution investigates mean time to failure, mean unavailability and mean down time of an optical cross connect described by a complex reliability block diagram. In addition a sensitivity analysis is performed. All Monte Carlo simulations and Markov calculations are done by using a commercial software tool.
