Person to Person File Transfer and Sharing (P2P)
Everyone remembers the Napster scandal a few years ago. The Recording Industry Association of America (RIAA) pounced on the users of Napster with accusations of copyright violations and illegal distribution. What spurred the RIAA's furious assault was that the millions of Napster users had been sharing MP3 music files between themselves. These files, ripped from CDs or records, could be transferred in several minutes time over the Internet for free. Napster was a massive search engine that united all the people who had MP3's and it was the first massive P2P Network. Since then, scores of similar programs have appeared -Morpheus, BitTorrent, Ares, Kazaa, Guntella, and many others. These programs now allow users to share files from their computers with other users.
How P2P Works
The file networks run by these programs are based on the use of clients. A client is basically a server, either your own server at home, or a central web server that routes signals from various computers. In any case, the clients are grouped into clusters. Each client knows the “contact info” - the IP addresses, usable ports, and shared files - of other computers in it's cluster. These clusters overlap and when you run a search for a file of any kind, you get results from all the clusters in the P2P system.
When actually downloading a file, the P2P networks use an ingenious method of accelerating the download process. The search engine finds multiple users with the same file and then downloads parts of the file from each user. Each file arrives at your computer in pieces, allowing for much quicker transfer times and when downloaded, the program reconstructs the file as a whole. The first mass P2P was Napster and it was solely music based but these days you can find everything from movies and photos, to news documents, and shareware programs.