FansyRoute: adaptive fan-out for variably intermittent challenged networks

Abstract

We consider the problem of routing in a highly and variably intermittent wireless network to support delay-intolerant as well as delay tolerant applications. Specifically, the links in such a network are too volatile to maintain a consistent topology, rendering most MANET protocols ineffective. At the same time, store-and-forward (DTN) techniques are not an option due to the need for delay intolerance, and may be unnecessary due to the likely availability of contemporaneous, albeit rapidly changing, paths. We present a novel routing mechanism called FansyRoute, aimed at this challenged region between MANETs and DTNs. FansyRoute adaptively adjusts the number of replications (fan-out) on a per-node basis, taking into account the level of intermittency along the path to the destination and a user-specified tradeoff between delivery expectation and the cost of replication. We study the performance of two FansyRoute schemes on a prime example of such variably intermittently connected networks, namely asynchronously duty-cycled sensor networks. Using ns-3, we compare FansyRoute to OLSR, AODV and Flooding. The results show that in an intermittent network, FansyRoute can deliver 50% more packets than the single path protocols, with less than 5% of the replication incurred by flooding. FansyRoute replicates only when needed and the replication is restricted to the challenged regions of the network.