Peer-to-Peer is a network model where two or more computers form an unstructured and informal network relationship. With pee-to-peer, computers form trust relationships that enables them to share resources. The shared resource is typically files, which was how Napster allowed computers to access and share movies and music files on members’ hard-dives. It isn’t just files however, Skype also uses a peer-to-peer model, in this case it is sharing a resource, network bandwidth. Universities especially those undertaking scientific research often build peer-to-peer networks in order to share resources, in this case it is computing power or CPU cycles. The key differentiator between a peer-to-peer network and other types of structured centralized computer networks is that with peer-to-peer network there is no server, all computers on the network have equal status. The members of a peer-to-peer network are all publishers and consumers of resources so there is no need for a centralized server.
Peer-to-peer technology has many applications typically it is used in Instant messaging and Chat programs as well as in VoIP applications such as Skype. It is also very popular for content delivery because of the way the network model works. In a traditional client/server model the more clients join the network the harder the server has to work and the less efficient the network becomes as more and more clients consume the servers finite resources. However, with peer-to-peer the more hosts join the network and share their resources the pool of available resources increases and the more efficient the network becomes. This makes peer-to-peer a very attractive operating model for any content delivery publisher as it curtails the need for heavy upfront investment in servers and mitigates the downside of growth making the network highly scalable.
Peer-to-peer gained notoriety through bandwidth hogging application as users’ downloaded movies and videos through applications such as Gnutella, Bit-Torrent and Pirate Bay. Because of this, they were the focus of network security who tried to block peer-to-peer applications usin