Performance Evaluation of the Advanced Network Tracker for BitTorrent

BitTorrent, a popular Peer-to-Peer (P2P) protocol, has recently engendered considerable controversy. Many P2P applications implement a variant of the protocol due to its cost-effective scalability. However, for Internet Service Providers (ISPs) the protocol is notorious for its high network cost. To reduce these costs, ISPs have deployed network devices to detect and throttle BitTorrent traffic. In response, application developers have begun encrypting the protocol's traffic to avoid ISP-detection. These actions perpetuate a "cat and mouse" game between ISPs and developers. Recent proposals to reduce BitTorrent's network cost involve either changing the protocol or deploying ISP-managed services. These proposals require broad adoption by developers to significantly benefit ISPs. In this paper, we propose a solution that is universally applicable to all BitTorrent clients and provides savings for ISPs out of the box. We have developed a high performance network device, called the Advanced Network Tracker (ANT), which reduces BitTorrent network cost without changing the protocol. Moreover, ANT requires no explicit communication between client applications and ISPs. It inspects packets on the wire to identify BitTorrent traffic to discover local peers sharing similar files. To reduce network costs, ANT localizes traffic to an ISP's network by informing local peers about each other. In this work, we implement a working prototype of ANT using Network Processors (NP) for high throughput packet processing. In addition, we evaluate our implementation on the Open Network Lab's [ONL] NP-based programmable routers. Our evaluation shows ANT has a considerable impact on cross-ISP traffic. And equally important, it has a negligible impact on client performance.