Accurate reliability and availability models for direct interconnection networks

Fault tolerance in multicomputer interconnection networks has been traditionally studied by determining the worst possible combination of faulty components that causes its failure and then assuming that this will occur. But, the probability of the worst possible combination is usually low, and the routing algorithm may be able to find a route between source and destination nodes. The network dependability parameters computed according to this approach will be underestimated. In this paper we propose a methodology for accurately evaluating interconnection network dependability. In addition, we apply it to obtain an accurate estimation of the reliability and availability parameters in a 2-D mesh, taking into account network size, routing algorithm, failure and repair rates of nodes, and coverage. Finally we compare the computed results under both approaches.