Availability Evaluation of Quorum-Based Mutual Exclusion Schemes in General Topology Networks

The use of quorums is a well-known approach to achieving mutual exclusion in distributed environments. In this paper, we propose a new availability evaluation method for quorum-based mutual exclusion schemes in the presence of failures. Most of the previously proposed methods take neither the topology of systems nor link failures into consideration, and exhaustive state enumeration has been the only approach that can deal with them so far. By incorporating a notion called Minimal Quorum Spanning Trees, this method can efficiently evaluate the availability of quorum-based mutual exclusion schemes in general topology networks with unreliable nodes and links. Through experimental results, we show the superiority of the proposed method over exhaustive state enumeration.