Routing Primitives for Wireless Mesh Networks: Design, Analysis and Experiments

In this paper, we consider routing in multi-hop wireless mesh networks. We analyze three standardized and commonly deployed routing mechanisms that we term "node-pair discovery" primitives. We show that use of these primitives inherently yields inferior route selection, irrespective of the protocol that implements them. This behavior originates due to overhead reduction actions that systematically yield insufficient distribution of routing information, effectively hiding available paths from nodes. To address this problem, we propose a set of "deter and rescue" routing primitives that enable nodes to discover their hidden paths by exploiting already available historic routing information. We use extensive measurements on a large operational wireless mesh network to show that with node-pair discovery primitives, inferior route selections occur regularly and cause long-term throughput degradations for network users. In contrast, the deter and rescue primitives largely identify and prevent selection of inferior paths. Moreover, even when inferior paths are selected, the new primitives reduce their duration by several orders of magnitude, often to sub-second time scales.