P2P Filesharing - Technical Background
Note: access to an entire paper written on this subject is available here: GOOGLE BOOK SEARCH, BITTORRENT AND COPYRIGHT LAW
File-sharing is the practice of making files available for users to download over the Internet. File sharing often uses a peer-to-peer model (P2P) in which files are stored on users’ personal computers. The P2P model provides a number of advantages for sharing files including eliminating the need for server storage space and enabling faster file downloads because the file may be available on many users’ computers. The combination of 1) popular files, 2) ease of copying digital media, and 3) high-bandwidth Internet access have made file-sharing over P2P networks explode. While file sharing is a legal technology with many legal users, most users use P2P technology to download copyrighted materials including music and movie files. The motion picture and record industries have engaged in significant litigation to try to curtail these infringements. This article will argue that BitTorrent, a new P2P network technology should not be liable for the copyright infringements of its users based on a theory of contributory infringement for distributing its product or on a theory that it induced its users to commit infringement.
Technical Background
File-sharing is the practice of making files available for users to download over the Internet. File sharing often uses a peer-to-peer model (P2P) in which files are stored on users’ personal computers. The file sharing network consists of the protocols for how the sharing of files will take place. Typically, users connect to the network using software programs installed on their own machines. The combination of 1) popular files, 2) ease of copying digital media, 3) high-bandwidth Internet access have made file-sharing over P2P networks explode.
Napster
Napster was one of the first major P2P software applications and was available to download for free. Restricting file-sharing to only MP3 music files, Napster relied on centralized servers for storing an index of all the MP3 files shared by users logged into the network. After registering, a user could access and search the index and then download the files directly from one of the other users’ computers. Napster was successfully shut down through legal attacks from the record industry and has since reemerged as a commercial online service.
Aimster
After the collapse of Napster other P2P networks and P2P client software applications emerged including Aimster. Aimster, a venture capital backed company, leveraged AOL’s instant messaging application (AIM) to allow users to see their friend’s file listings and share files using the AIM network. It consisted of a proprietary software client that could be downloaded for free. Users of Aimster could leverage AOL’s network of users and search for file’s shared over that network. Aimster’s server would search the computers of Aimster users to find the file requested and would instruct the computer to transmit the file to the requester.
Grokster & StreamCast
Grokster and StreamCast were additional P2P client applications that became popular after the collapse of Napster due, in part, to their decentralized architecture. Grokster’s client application licensed the FastTrack network technology. StreamCast developed a similar product but relied on the Gnutella network. Therefore, Grokster and StreamCast were all new client software applications that were used to connect to the FastTrack and Gnutella’s decentralized P2P networks to enable their users to share files. These networks differed from Napster in two primary ways: 1) users could search for any file type (they were not restricted to MP3s like in Napster), and 2) the network was decentralized (no centralized index servers). The decentralized network architecture prevented any single broken link, such as Napster’s index servers, from bringing down the network. Grokster removed the need for centralized index servers through its use of supernodes. Whenever a powerful computer with a high speed connection running Grokster connected to the FastTrack network, it automatically became a supernode and acted as a temporary indexing server for other clients on the network. It was believed that the decentralized nature of the network would insulate it from legal threats.
eDonkey
Other P2P networks have also emerged. The eDonkey network emerged supporting the ability for users to begin sharing segments of files before they had been fully downloaded. This speeds up the distribution and sharing of files on the network. Moreover, eDonkey clients used to connect to the eDonkey network often employed rating systems in which users who shared more files were rewarded with priority when downloading. In 2004, the eDonkey network became the most widely used file sharing network on the Internet.
BitTorrent
BitTorrent is the name of a P2P technology created by Bram Cohen in 2002. BitTorrent has proven to be very adept at sharing large files such as movies, television shows and software applications. Cohen says that he developed BitTorrent because his friends in the “jam band” community needed a better way to legally download entire concerts rapidly. Traditional P2P technologies were proving to be unreliable and too slow.
The name “BitTorrent” refers to the network protocol, the original client application used to connect to the network, and the .torrent file type used for sharing files. To share a file using BitTorrent, a file is broken up into smaller fragments. A .torrent file is created that provides information on how to reconstruct these fragments as well as information on how to find the relevant file fragments on the network. Once a fragment of a file has been downloaded, that fragment immediately becomes available to be downloaded by other clients. This architecture helped BitTorrent address one of the common problems with conventional file sharing applications. With conventional P2P technology, high demand for a particular file could lead to bottlenecks, particularly for very large files that took a long time to download. It took longer for larger files to spread through the network because each user had to download the entire file before they could share it with others. BitTorrent’s approach of breaking files into process fragments meant that users could share portions of the large files faster, relieving the stress on the original host server. Similarly, while nodes in other file sharing networks share and download large numbers of files making the bandwidth for each file smaller, users of BitTorrent usually concentrate on transferring a single file or a small collection of files that make these transfers faster.
One primary difference between the BitTorrent network and most other P2P networks is that the original client applications could not search the web for .torrent files. Therefore, to share and download files, a user had to find the .torrent files themselves. As a result, websites like Suprnova.org emerged that distributed .torrent files. While sites like Suprnova did not host the copyrighted files themselves, they provided the .torrent files for copyrighted music, movies, software applications and computer games.
