Quorum Based Distributed Conflict Resolution Algorithm for Bounded Capacity Resources

Abstract

The (m,h,k)-resource allocation is a conflict resolution problem to control and synchronize a distributed system consisting of n nodes and m shared resources so that the following two requirements are satisfied: at any given time at most h (out of m) resources can be used by some nodes simultaneously, and each resource is used by at most k concurrent nodes. The problem is a natural generalization of several well-studied conflict resolution problems such as mutual exclusion, k-mutual exclusion, generalized mutual exclusion and group mutual exclusion. The problem can be solved by employing an ℓ-mutual exclusion algorithm, however, it is inefficient in terms of the message complexity and the maximum degree hk of concurrency may not be achieved. We thus propose a new algorithm and a new quorum system (m, h, k)-coterie used in it, and show that all requirements of the problem are guaranteed and the maximum concurrency degree is achieved as desired. We also present a natural extension of the new quorum system which resolves a more general problem with distinct bounded capacities and also achieves the maximum degree of concurrency, $\sum^{h}_{i=1}{k}_{i}$, of the problem.