A multi-faced measurement study on a large private BitTorrent community

Private BitTorrent community is becoming increasingly popular, and generates a huge amount of Internet traffic. In this paper, we present a thorough measurement study on a famous private BitTorrent community, CHDBits. We find that the content of torrents published in this community are highly available, although many torrents may have been released for a very long time, and we also obtain that users in most torrents could download at a high rate. By studying user profiles, we show that many users have participated in multiple torrents, thereby generating a great amount of upload and download traffic. The user profiles also reveal that almost all users maintain a high share ratio, and are willing to contribute to content distribution by spending more time in seeding than in leeching (downloading). Our study suggests that the bandwidths of a user have a significant impact on their behavior. Low bandwidth users are more likely to participate in the torrents with a smaller content size or a higher popularity; compared with low bandwidth users, high bandwidth users tend to participate in more torrents, but spend much less time in seeding.