Assessing the impact of BitTorrent on DOCSIS networks

BitTorrent is a widely deployed peer-to-peer protocol that provides scalable file sharing capabilities. While BitTorrent applications contribute to the demand for high speed broadband access, they also contribute to the undesirable 80/20 effect wherein 80% of the bandwidth is consumed by 20% of the users. In this study we explore the impact that BitTorrent users can have on a DOCSIS cable network. We began the study by capturing packet traces of BitTorrent applications operating on two commercial DOCSIS cable networks. Next we developed for the ns-2 simulation tool a configurable mix of BitTorrent, Web browsing, and VoIP workloads and verified that the behavior of the simulated BitTorrent workloads to be consistent with the behavior observed on the commercial network. In this simulated environment, we show that as few as 15 BitTorrent users can significantly reduce the service quality experienced by other subscribers.