Topology-aware PEX for improving BitTorrent

In this letter, we propose one easily deployable traffic localization technique, tPEX for BitTorrent. Using peer exchange (PEX) of BitTorrent, tPEX injects a set of local peers to the local peers in the target network domain so that they realize the traffic localization. Through simulations, we show that, in AS with 200 simultaneous local peers, tPEX enables the local peers to download around 60% of content within the same AS. The traffic localization by tPEX also improves the download performance by 45%. Even in AS with 13 simultaneous local peers, tPEX enables the local peers to download around 35% of content within the same AS and improves the download performance by 17%.