TU Delft
The measurements
Parallel and Distributed Systems
EWI PDS MultiProbeThe Measurements
Quick links
overview pre-setup measurements

An overview of the May 2005 measurements
what did we measure?

Using the MultiProbe framework, we performed a large-scale measurement of BitTorrent, currently the dominant P2P file sharing network in terms of traffic, and its underlying Internet parts. The full data set resulting from the measurements is described in the data set page. The full data set is available for research from the download page. The detailed analysis of the measurement results can be found in the research page.

The pre-setup
brief description
The largest BitTorrent web site, May 2005
Table MP-1. The number of torrents (files) and users per measured BitTorrent web site.

In the pre-setup phase of the experiments, we first select the largest BitTorrent web site. We have developed size evaluators for four well-known BitTorrent web sites: Mininova (the replacement of the previously largest web site, SuprNova, which is now defunct), Novatina, Pirate Bay, and TorrentPortal. Table MP-1 shows the number of torrents (files) and users of each of these web sites; as Novatina was reporting exaggerated numbers of users and contained many broken links, we have removed it from further consideration. At the time of our measurements (May 2005), the dominant BitTorrent web site was Pirates Bay. Therefore, for measuring topology and path characteristics of overlay networks and the Internet, we set up MultiProbe to measure the BitTorrent/Pirates Bay environment.


The measurements
brief description

We have used two platforms for our measurements. For our active-start measurements, we have deployed MultiProbe on 100 of the 400 processors available on our Distributed ASCI Supercomputer. For our passive-start measurements, we used 50 PlanetLab nodes as peer points, and 300 PlanetLab nodes for traceroutes towards the peers that contacted the peer points. Scriptroute was of inestimable help for distributed software deployment and operation.

The largest BitTorrent web site, May 2005
Table MP-2. A summary of the characteristics of the tracked files.

We successfully tracked the top 2,000 files in the active-start measurements. Due to machine failures on PlanetLab, we successfully tracked only 695 of the originally intended top 750 files in the passive-start measurements (files ranked 155, 331-340, 405-410, and 716-750 were not tracked). The two sets of tracked files overlap. Table MP-2 shows the statistics of the tracked files. We define a shared file as a file shared using BitTorrent. The set of tracked shared files presents a wide range of values for shared file size, number of chunks, chunk size, and files in the torrent. The average shared file size is around 2-3GB, which shows that BitTorrent is mostly used for large-sized transfers. We also find that most torrents are archives, and the average number of files per archive is around 50.


Last modified: Thu, 13 October, 2005 6:34 PM
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