SAT-Match: a self-adaptive topology matching method to achieve low lookup latency in structured P2P overlay networks

摘要

Summary form only given. A peer-to-peer (P2P) system is built upon an overlay network whose topology is independent of the underlying physical network. A well-routed message path in an overlay network with a small number of logical hops can result in a long delay and excessive traffic due to undesirably long distances in some physical links. We propose an effective method, called SAT-Match, to adoptively construct structured P2P overlay networks, aiming at significantly reducing the lookup routing latency. In this method, each joining peer is initially guided to find a physically close neighbor to connect with. After then, its overlay location is adoptively adjusted whenever a location mismatch is detected. The topology matching optimization in our method solely relies on local neighborhood information. Compared with existing topology matching methods, our method addresses their three limitations: (1) heavily relying on global information about the Internet by using landmark-based measurements, (2) lacking adaptation to frequent peer movement in a dynamic environment, such as mobile networks, and (3) insufficiently accurate in topology matching due to the lack of adaptive topology adjustment. We have evaluated our method in the content-addressable network (CAN), a representative structured P2P system with a strong tolerance to frequent peer arrivals/departures. Through intensive simulation experiments on large scale CAN overlays, we have shown the effectiveness of SAT-Match. Our method can achieve average logical/physical link latency reduction rate by up to 40%. It also outperforms "landmark binning", a method utilizing global information by up to 20%. Finally, combining with the landmark binning method, SAT-Match can achieve up to 60% latency reduction.