What is BitTorrent?

BitTorrent is an open, peer-to-peer protocol designed for transferring large files. The BitTorrent protocol allows users to share a file with other users while they are downloading that file, which maximizes the efficiency of network bandwidth. The more users who download a particular file, the more copies of the file are available for downloading and hence the faster the file is transferred.

Files are generally broken down into pieces of approximately a quarter megabyte each; and the pieces get distributed to different peers. When someone goes to download a particular file, the pieces are basically re-assembled from the different peers onto the computer of the person downloading the file. The downloader also becomes a peer and offers the file for download. This is why the more peers, the faster and more efficient the download process.

Downloading torrent files
Downloading torrent files is not the same as other file sharing networks. First you have to find the torrent file you want to download by searching the web. Once you locate the file you want, you have to use a BitTorrent Client to get it. There are a few different BitTorrent clients to choose from, and most of the popular ones are reviewed on our BitTorrent clients page. BitTorrent clients, including the Official BitTorrent Client and Azureus are free to use and very easy to install.

Torrent files and tracking servers
When a user wishes to download a file using the Bit Torrent protocol, they begin by downloading a Torrent file. The Torrent file contains important information about the file to be downloaded. The BitTorrent client interprets important information which is contained in the Torrent file (.torrent).

Similar to peer-to-peer file transfers, with the Bit Torrent protocol users connect to each other directly to send and receive portions of the file. These connections are governed by a tracking server, which manages these connections and aids each user in getting the pieces of the file they need. Because the tracking server manages only the connections themselves, and not the actual content being shared, it can manage a large number of users with relatively limited tracker bandwidth.

In a typical situation, the user requires a seed to download a file using the Bit Torrent protocol. A seed is a computer that has the entire file to be downloaded, and has made that file available for downloading. Anyone can make their computer a seed by simply downloading a torrent file and leaving the connection open to facilitate other users wishing to download the same file. A user may download a file directly from the seed, or from another computer who has either directly or indirectly downloaded the file from the seed.

Because a orrent file is distributed in chunks, it is preferable (yet not necessary) to have a seed (with a copy of the complete file) in order to download a complete file. It is only necessary to have a complete copy of the file amongst all of the computers currently downloading the file (several computers downloading the same file are known as a swarm). Each of these computers (peers) will share the necessary file chunks with each other, allowing each peer to have a complete copy of the file. The tracking server plays a large part in assisting peers with gathering the required chunks to make the complete file being downloaded.

BitTorrent popularity
The BitTorrent file sharing protocol is one system that has weathered many storms, particularly compared with many of the other file sharing systems that have since been shut down due to legal issues related to the illegal distribution of copyrighted material such as music and movies. BitTorrent does not lend itself well to the sharing of illegal material since the trackers can be traced to individuals. Since 2002, BitTorrent files have become one of the most popular file sharing formats because the protocol can support large numbers of downloaders with consistent stability.

How does BitTorrent compare to other forms of file sharing?