Bound computation of dependability and performance measures

We propose a new method to obtain bounds of dependability, performance or p erformability measures concerning complex systems modeled by a large Markov model. It extends previously published techniques mainly designed to the a nalysis of dependability measures only and working under more restrictive c onditions. Our approach allows us to obtain tight bounds of performance mea sures on certain cases and, in particular, on models having an infinite sta te space. We illustrate the method with some analytically intractable open queuing networks, as well as with large dependability models.