Data Plane Throughput vs Control Plane Delay: Experimental Study of BitTorrent Performance

In this paper, we address the trade-off between the data planeefficiency and the control plane timeliness for the BitTorrent performance.We argue that loss-based congestion control protocols can fill largebuffers, leading to a higher end-to-end delay, unlike low-priorityor delay-based congestion control protocols.We perform experiments for both the uTorrent and mainline BitTorrentclients, and we study the impact of uTP (a novel transport protocolproposed by BitTorrent) and several TCP congestion control algorithms(Cubic, New Reno, LP, Vegas and Nice) on the download completion time.Briefly, in case peers in the swarm all use the same congestioncontrol algorithm, we observe that the specific algorithm has only alimited impact on the swarm performance. Conversely, when a mix of TCPcongestion control algorithms coexists, peers employing a delay-basedlow-priority algorithm exhibit shorter completion time.