Hybrid routing in clustered DTNs with message ferrying

Abstract

The mobile wireless research community has invested in the development of routing algorithms and protocols for two distinct environments. The mobile ad-hoc network (MANET) environment is generally assumed to contain relatively dense nodes connected by multi-hop paths, where disconnection is rare. The disruption tolerant network (DTN) environment is generally assumed to contain relatively sparse nodes that are frequently disconnected. We are interested in a different environment in which clusters of nodes have MANET-like dense connectivity, while there is DTN-like sparse connectivity between clusters. We focus in this paper on the case of stationary clusters, where message ferrying provides inter-cluster connectivity. Our routing approach combines message ferry routing with MANET routing through the use of gateway nodes. To best utilize gateway nodes, we develop various algorithms for data aggregation at gateways and transmission scheduling between gateways and the ferry. To further improve performance, we design algorithms to customize ferry routes according to node location and traffic condition. Our hybrid routing schemes are evaluated via extensive simulations.