Jointly Optimal Routing and Caching for Arbitrary Network Topologies

We study a problem of minimizing routing costs by jointly optimizing caching and routing decisions over an arbitrary network topology. We cast this as an equivalent caching gain maximization problem, and consider both source routing and hop-by-hop routing settings. The respective offline problems are NP-hard. Nevertheless, we show that there exist polynomial time approximation algorithms producing solutions within a constant approximation from the optimal. We also produce distributed, adaptive algorithms with the same approximation guarantees. We simulate our adaptive algorithms over a broad array of different topologies. Our algorithms reduce routing costs by several orders of magnitude compared with prior art, including algorithms optimizing caching under fixed routing.