A Performance Study of Peer-assisted File Distribution with Heterogeneous Swarms
Peer-to-peer file-sharing protocols, such as BitTorrent, have been widely used to improve the performance and scalability of file distribution systems. In this paper, the authors study the performance of peer-assisted file distribution systems with heterogeneous peers. Based on a measurement study of BitTorrent on PlanetLab, they made two key observations: there is a fixed pattern in the utilization of the available bandwidth over the course of a download, and peers enjoy an amount of service that is commensurate with their contribution. Building on these insights, they developed an analytical model to estimate the download time for each class of peers in a well-provisioned peer-assisted file distribution system based on BitTorrent.