Performance analysis of BitTorrent and its impact on real-time video applications

BitTorrent and similar peer-to-peer file sharing applications can represent a large portion of network traffic. Despite the advantages for BitTorrent users, it can unfairly consume access link bandwidth from other user(s) and applications. It can also rapidly fill up buffers at access routers. We have used a detailed model of the BitTorrent protocol to analyze its performance and impact on real-time video traffic. We have shown that increasing the number of BitTorrent clients and/or upload connections can cause a decrease in download rate due to delayed TCP acknowledgements. We also show the effect of access router buffer size on performance: too small reduces BitTorrent’s upload rate, too large increases video jitter and delay.