An Adaptive Response Routing Mechanism to Improve DHT Performance in the Presence of NATs

Asymmetric network connectivity, frequently the result of NATs in the network environment, can significantly impact the selection of an appropriate DHT response routing technique. We show that neither response mechanism commonly used today (symmetric recursive or direct response) function well for all network NAT densities. We present an adaptive response routing algorithm for use in generic libraries or protocols where the deployment environment is not known in advance. Through worst-case analytical analysis and average-case simulation we show that our technique offers a significant performance advantage in environments (such as the Internet) where NAT densities are not known a priori.