Abstract
Peer-to-peer file sharing exploded into the public consciousness with the release of Napster in 1999. Napster sparked a revolution in computer-mediated communication and within a few years, peer-to-peer had replaced client-server as the dominant communications paradigm of the Internet. Peer-to-peer has also redefined the role of home users, empowering them to produce and distribute content free from control or censorship by third parties. The importance of the peer-to-peer revolution has been reflected by significant research and business activity, although considerable technical and socio-technical problems still remain. This chapter discusses the emergence of peer-to-peer systems as a medium for computer-mediated communication and how these systems have evolved to tackle new challenges. This is done in the context of a case-study of Gnutella, one of today’s most significant peer-to-peer file sharing systems.
Key Terms in this Chapter
Free-Riding: A socio-technical problem wherein users of anonymous peer-to-peer file sharing systems download files from the system, but do not upload.
Search Horizon: A critical limitation of second-generation or decentralized peer-to-peer systems, wherein users cannot discover resources distant from them on the P2P network.
Peer-to-Peer (P2P): Peer-to-peer is a class of applications that takes advantage of resources - storage, cycles, content, human presence - available at the edges of the Internet.
Third-Generation P2P Systems: Third generation or hybrid P2P systems combine elements of first and second-generation approaches. They assign greater responsibility to more capable peers. Examples include Gnutella 0.6 and Kazaa.
Third-Generation P2P Systems: Third generation or hybrid P2P systems combine elements of first and second-generation approaches. They assign greater responsibility to more capable peers. Examples include Gnutella 0.6 and Kazaa.
Client-server: The dominant form of Internet communication prior to the emergence of peer-to-peer. In client-server systems, services are provided only by powerful servers, and consumed by less powerful clients such as home and office computers.
First-Generation P2P Systems: First generation or semi-centralized P2P systems are those which use servers to mediate interaction between peers. Examples include Napster and Seti@Home.
Client-server: The dominant form of Internet communication prior to the emergence of peer-to-peer. In client-server systems, services are provided only by powerful servers, and consumed by less powerful clients such as home and office computers.
P2P Topology: A P2P topology describes the network connections which link the peers participating in a P2P system.
Search Horizon: A critical limitation of second-generation or decentralized peer-to-peer systems, wherein users cannot discover resources distant from them on the P2P network.
Second-Generation P2P Systems: Second generation or decentralized P2P systems are entirely decentralized and treat all peers equally. Examples include Gnutella 0.4 and Freenet.
Second-Generation P2P Systems: Second generation or decentralized P2P systems are entirely decentralized and treat all peers equally. Examples include Gnutella 0.4 and Freenet.
Free-Riding: A socio-technical problem wherein users of anonymous peer-to-peer file sharing systems download files from the system, but do not upload.
Peer-to-Peer (P2P): Peer-to-peer is a class of applications that takes advantage of resources - storage, cycles, content, human presence - available at the edges of the Internet.
First-Generation P2P Systems: First generation or semi-centralized P2P systems are those which use servers to mediate interaction between peers. Examples include Napster and Seti@Home.
P2P Topology: A P2P topology describes the network connections which link the peers participating in a P2P system.