What is Peer-to-peer technology?
Peer-to-peer technology (P2P) is an alternative to a client-server network. P2P allows computer hardware and software to function without requiring special server devices.(1) This technology has become popular for the use of file sharing between users. In a client-server system the dominant computer is the server which has several clients, the clients can communicate and exchange resources with one another but only by going through the server.(2) In a P2P system the clients can communicate and exchange resources directly with one another without the use of a server because control is decentralized, each client is treated as both a server and a client.(2)
Types of P2P Networks
There are three basic types of P2P networks: Pure P2P, Hybrid P2P, and Mixed P2P.(2) In a Pure P2P network the peers act as both clients and servers, and there is no central server or router.(2) In a Hybrid P2P network there is a central server that keeps information on peers and responds to requests for that information however the peers are responsible for hosting the information (the central server does not store files), letting the server know which files they want to share, and for downloading the shareable resources that other peers request.(2) Finally there is the Mixed P2P network which simply contains characteristics of both the Pure and Hybrid types of P2P networking.(2)
Breif History of P2P
The Internet was originally set up in the late 1960’s as a peer-to-peer system; the first hosts on ARPANETwere connected to each other as equal peers rather than as client-server.(2) The change from P2P to client-server based systems occurred with the rise of internet browsers in the mid-nineties.(2) However since then there has been a great resurgence of the use of P2P technology for the use of file sharing. Napster was one of the major players associated with this resurgence.(3) Napster, which is an example of a Hybrid P2P network, was invented by a 19 year old college student, Shawn Fanning, for the purpose of sharing MP3 files.(3) At first the service was free, however in 2000 concern was growing in record companies and the band Metallica sued Napster for copyright infringement.(3) Metallica won the suit in 2001 granting a large settlement to songwriters and producers as well as a percentage of the money Napster brings in from its pay service which began in 2003.(3) Since the Napster ordeal there have been many other P2P programs emerge some of the more popular ones include Rhapsody, KaZaa, and WinMP. All of these programs use P2P technology that allows for limitless file sharing for a monthly subscription fee.
1.) http://compnetworking.about.com/od/p2ppeertopeer/g/bldef_p2p.htm
2.) http://ntrg.cs.tcd.ie/undergrad/4ba2.02-03/p4.html
3.) http://ntrg.cs.tcd.ie/undergrad/4ba2.02-03/p1.html