Bit Torrent is a popular P2P network for sharing and downloading large files. In one example of commercial use, Lindows distributes its LindowsOS software via Bit Torrent.

Bit Torrent is centered around files. Key features include file connection trackers, metadata torrent files, multisource downloading, partial file downloading, and automatic sharing of partially and fully downloaded files, all fully supported by TrustyFiles.*   

The overall downloading experience is similar to other networks. Many files have no sources at any given time. A few may have one active file source. Occasionally you may have a file with multiple sources that downloads quickly. Since Bit Torrent's files are generally large (the Lindows OS is 500MB), it may take many hours or days to fully download a file.

Bit Torrent uses a different architecture compared to networks like Kazaa and Gnutella. Other networks use supernodes that reside on servers or other user computers. These supernodes contain the addresses of other users. Once you connect to other users, your PC propagates search requests throughout the network.

The Bit Torrent network doesn't support open searches, connect all users, or propagate requests. Instead Bit Torrent has a central server node called a Tracker for each file. Like other P2P networks, this node contains the addresses of other users. But in Bit Torrent the tracker contains only the addresses of users who also seek or share that specific file. Bit Torrent makes separate connections to each Tracker for each file you’re downloading or uploading.

Finding and downloading files through Bit Torrent is more difficult than other networks since you can’t run a direct file search on the network and Trackers must be online to enable file sharing. Bit Torrent is a two step process that uses Torrents, which have file names that end in .torrent. Torrents specify one or more files and contain related info, such as a tracker location, file name, and file ID (hash). You must first download the torrent and then have your P2P software process the torrent and then download the target file.

Next - Finding torrents

* - TrustyFiles automatically shares downloaded files and supports partial file downloading within each of its networks. However not all software clients on Kazaa and Gnutella networks do this.