A New Fault-Tolerant Routing Algorithm for OTIS-Cube Using Unsafety Vectors

Abstract

This article proposes a new fault-tolerant routing algorithm for the well-known class of network, OTIS-cube. In this new proposed algorithm, each node A starts by computing the first level unsafety set, S1A, composed of the set of unreachable direct neighbours. It then performs m-1 exchanges with its neighbours to determine the κ-level unsafety sets SκA for all 1≤κ≤m, where m is an adjustable parameter between 1 and 2n+1. The κ-level unsafety set at node A represents the set of all faulty nodes at Hamming distance κ from A that are either faulty or unreachable from A due to faulty nodes or links. Equipped with these unsafety sets, the authors show how each node calculates numeric unsafety vectors and uses them to achieve efficient fault-tolerant routing. The article also presents a performance analysis through extensive simulation experiments proving the superiority of the proposed algorithm using the set of unsafety vectors by showing how the destination is reached by using these sets of unsafety vectors. The simulation results are obtained in terms of routing distances and percentage of reachability.