Protocols for Enhancing Gateway Dependability in Hybrid Mobile Ad Hoc Networks

Abstract This paper relates to mobile ad hoc networks consisting of groups of nodes that may be geographically isolated, or may have mutually incompatible networking technologies. The standard method to enable connectivity amongst them is to use gateways that can communicate across platforms, and thus form a hybrid "network of ad hoc networks." However, such a hierarchical network is particularly vulnerable to single points of failure (at the gateways). This article describes techniques that enable such gateways to incorporate a measure of security and distributed fault tolerance. Algorithms are designed to employ redundant gateways in each ad hoc domain that, along with node signalling schemes, ensure continued operation and graceful degradation of the network performance in the face of node/gateway failures. A simulation study shows that the proposed algorithms are tractable, implementable, and have relatively modest computational and network overhead