Understanding BitTorrent's Suitability in Various Applications and Environments

Peer-to-peer systems have recently emerged as an attractive alternative to client/server approaches, especially in the area of content distribution. By efficiently leveraging the available upload bandwidth of the end users, BitTorrent becomes a de facto standard for scalable content distribution. Inspired by its success, many companies try to shift the major upload burden from their rented source servers to end users by using this protocol, since many hosting sites charge them based on the used egress capacity. In this paper, we perform an in-depth study of the overall performance of BitTorrent in its entirety, in order to get a broader understanding of its suitability for different applications domains. We analyze its performance from a bifocal perspective, namely that of the content providers and that of the end users. In this context, we find that the decrease of the source server's upload capacity has a highly negative impact on the overall protocol performance. In addition, it is shown that giving incentives to peers to stay online after completing downloading does not pay off.