Peer to Peer

A peer-to-peer (P2P) network is a type of decentralized and distributed network architecture in which individual nodes in the network (called "peers") act as both suppliers and consumers of resources, in contrast to the centralized client–server model where client nodes request access to resources provided by central servers.

In a peer-to-peer network, tasks (such as searching for files or streaming audio/video) are shared amongst multiple interconnected peers who each make a portion of their resources (such as processing power, disk storage or network bandwidth) directly available to other network participants, without the need for centralized coordination by servers.

History
While P2P systems had previously been used in many application domains, the concept was popularized by file sharing systems such as the music-sharing application Napster (originally released in 1999). The peer-to-peer movement allowed millions of Internet users to connect “directly, forming groups and collaborating to become user-created search engines, virtual supercomputers, and filesystems.”

The idea of peer-to-peer began in the 1960s, when ARPANET was created as a network to share files between US research facilities and every host was seen as equal, none more important than the others. As a precursor to the Internet, ARPANET was a successful client-server network where “every participating node could request and serve content.” However, ARPANET was not self-organized and it lacked the ability to “provide any means for context or content based routing beyond ‘simple’ addressed based routing.”

Therefore, a distributed messaging system that is often likened as an early peer-to-peer architecture was established: USENET. USENET was developed in 1979 and is a system that enforces a decentralized model of control. The basic model is a client-server model from the user or client perspective that offers a self-organizing approach to newsgroup servers. However, news servers communicate with one another as peers to propagate Usenet news articles over the entire group of network servers.

In May 1999, with millions more people on the Internet, Shawn Fenning introduced the music and file-sharing application called Napster. Napster was the beginning of peer-to-peer networks, as we know them today, where “participating users establish a virtual network, entirely independent from the physical network, without having to obey any administrative authorities or restrictions.”

P2P Networks
According to Wikipedia, “file sharing is the practice of distributing files or providing access to digital stored information, such as computer programs, documents or multimedia.” Whereas, P2P (peer-to-peer) file sharing is done with the help of downloading software such as Torrent, Kaaza and Lime Wire. Users use software to connect into P2P network, where they find vast variety of different files available for direct download from other users on the network. P2P software breaks large files into smaller portion, which is being uploaded from different servers and then reassembled/combined by the downloading software. Peer-to-peer file sharing is not limited to music sharing, but also e-books, movies, TV shows, software and much more. Nevertheless, I think the P2P file sharing will grow over the years because it is cheap and allows instance transferring of data.