Self-Stabilizing Prefix Tree Based Overlay Networks

Abstract

Computing over large platforms calls for the ability to maintain distributed structures at large scale. Among the many different structures proposed in this context, the prefix tree structure has been identified as an adequate one for indexing and retrieving information. One weakness of using such a distributed structure stands in its poor native fault tolerance, leading to the use of preventive costly mechanisms such as replication.Self-stabilization is a suitable approach to design reliable solutions for dynamic systems, and was recently enhanced with new models to be able to deal with large scale dynamic platforms. A self-stabilizing system is guaranteed to reach a correct configuration, whatever its initial state is. Following this path, it is becoming possible to make distributed structures self-stabilizing at large scale.In this paper, we focus on making tries self-stabilizing over such platforms, and propose a self-stabilizing maintenance algorithm for a prefix tree using a message passing model. The proof of self-stabilization is provided, and simulation results are given, to better capture its performances. Still based on simulations, we provide evidences that the protocol, beyond its capacity to repair the structure, can significantly improve the system’s availability, even when the system is not yet stabilized.