R/Kademlia: Recursive and topology-aware overlay routing

Structured peer-to-peer overlays offer a basis for a broad range of applications, such as distributed storage, application layer multicast, and mobility support. This paper introduces R/Kademlia, a low bandwidth and low latency variant of the popular overlay protocol Kademlia. R/Kademlia utilizes recursive overlay routing instead of iterative lookups of keys, thus a higher routing performance can be achieved in network scenarios with churn rates that are characteristic for public KAD networks. Both Proximity Routing and Proximity Neighbor Selection are effectively applicable, which leads to a further decrease of routing latencies. Similar to the original protocol, nodes in a R/Kademlia network meet other nodes during user-triggered routing procedures, hence no expensive periodic tasks are needed. For the simulative evaluation of R/Kademlia, the Performance vs. Cost framework (PVC) and the overlay framework OverSim were employed, where both routing modes-iterative and recursive-were simulated and compared in different network scenarios with varying churn rates.