This paper presents a new recursive algorithm for computing bounds on the reliability of a directed, source-sink network whose arcs either function or fail with known probabilities. The reliability is the probability that a path (consisting only of functioning arcs) exists from the network\´s source to its sink. The algorithm is based on a partitioning of the nodes of the network into subsets S1, S2,..., SP such that all predecessors of a node belonging to Sp(2)
\n\n\t\t