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Location Proxies and Intermediate Node Forwarding for Practical Geographic Forwarding

Douglas S. J. De Couto and Robert Morris

Abstract

Two main problems prevent the deployment of geographic forwarding in real systems: geographic forwarding requires that all nodes know their locations, and it has trouble routing around local dead ends. This paper presents practical solutions to each problem.

The location proxy technique allows a node that does not know its location to find a nearby location aware node to use as a proxy for geographic forwarding. The technique works well over a large range of densities of location aware nodes, and allows a tradeoff between bandwidth used for routing information and expense of providing location information.

The intermediate node forwarding (INF) mechanism is a probabilistic solution for routing around bad geographic topologies via intermediate geographic locations. Existing solutions unrealistically assume that nodes have identical radio propagation; INF works on a restricted set of situations but makes assumptions that better match reality.

Experiments using the ns simulator show that location proxies and INF are effective enough to make geographic forwarding practical. We believe geographic forwarding will enable scalable ad hoc networking.

MIT Laboratory for Computer Science technical report MIT-LCS-TR-824, June 2001 (BibTeX entry)

Paper text: PDF, PS, gzipped PS

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