An Efficient and Fault-Tolerant Update Commitment Protocol for Weakly Connected Replicas

Mobile and other loosely-coupled environments call for decentralized optimistic replication protocols that provide highly available access to shared objects, while ensuring eventual convergence towards a strongly consistent state. In this paper we propose a novel epidemic weighted voting protocol for achieving such goal. Epidemic weighted voting approaches eliminate the single point of failure limitation of primary commit approaches. Our protocol introduces a significant improvement over other epidemic weighted voting solutions by allowing multiple, happened-before related updates to be committed at a single distributed election round. We demonstrate that our protocol is especially advantageous with the weak connectivity levels that characterize mobile and other loosely-coupled networks. We support such claims by presenting comparison results obtained from side-by-side execution of reference protocols in a simulated environment.