P2P network

Formation stages

Napster created by the American student Sean Fanning for the simplified exchange of musical files (to Napster users could exchange files among themselves through FTP, IRC, Usenet and some other services, but data, extremely inconvenient for transfer of large volume) became the first P2P network in June, 1999. Network functioning was controlled by several central servers on which were stored a log of search and the downloaded files of users which used the client application of the same name. Process of filesharing worked according to the following scheme: the user entered the name of the MP3-file into a search line then the client program sent a request for the central server; then, the application received the list of the computers connected at present to Napster on which this composition was available. 2 years later, in July, 2001 the network was closed because of distribution of pirated content.

Gnutella, the project created by NullSoft and at the initiative of AOL, but which stopped the existence almost at once after release became the second P2P network in the same 1999. At the heart of this network fully the key principle of peering - decentralization was already implemented: the network gave the chance to the user to look for and exchange all types of files with other owners of Gnutella without participation of any servers. Nevertheless several enthusiasts could revive a program code of Gnutella and recover the network protocol. As a result there was a mass of client programs for work with the Gnutella protocol: BearShare Pro, LimeWire extraordinary popular in the west of Morpheus and others.

One more product of "millennium" - the P2P network of eDonkey2000 implemented other principle of peering - a possibility of loading of the same file from different users. It looks as follows - the file is divided into small fragments, and is loaded from several sources available at the same time. The client application allows not only to load files, but also grants the right to other participants to download those fragments of the file that you already received. Nevertheless, and this P2P network stopped the existence (naturally, it was announced by developers, but not users who still use software clients of network - the most known of them to eMule).

Torrents

Evolution of P2P networks at the beginning of the 2000th years led to emergence of the most modern networks of file sharing, namely BitTorrent today (in 2001). Distinctive feature of this network - it is possible to load files in it only on condition of dedication of the (i.e., users should share the files among themselves). The central servers called by trackers allow to distribute evenly loading between the users downloading data (loading goes not only from distributing (sider), but also from those who download the file (feasts) at present). In new versions of the protocol systems which solve some of the previous problems were developed bestrekerny (engl. trackerless). Failure of the tracker in such systems does not lead to automatic failure of all network. The founder of BitTorrent Bram Cohen such scheme wanted to get rid of the main problem of all P2P networks - borders of growth of network (as most of users is used peering only for loading of content on the computer, but not for providing instead of the files to other users). In the BitTorrent system such behavior (such participants are called licher), in principle, is possible, but is usually strictly punished (mainly, the ban on the tracker).

Work in peering

For work in a P2P network (in particular, in BitTorrent), it is necessary to have the set software client (some of the most popular are μTorrent, BitComet, some file managers as Free Download Manager, GetRight, FlashGet, support net surfing) and also correctly configured network (to permit certain ports in the network screen, in certain cases to have registration on the tracker, the external IP address (for subscribers of "house networks").

It is necessary to begin work in peering with search: in a case with eDonkey network input of links to files the ed2k format is necessary (are low-appeal), in Gnutella and Kazaaa search is conducted in the software client, in a case with BitTorrent it is necessary to find and open in the software client the file with the .torrent expansion. Information on the loaded file (a name, the size), the ciphered codes of segments is stored in it (hash amount) and data on the computer of a sider. At start of the .torrent-file in the special client application loading of the selected file and, afterwards, downloading of the fragments loaded by you by other participants of filesharing will begin.

Legal issues

Client applications in itself for work in P2P networks are not illegal as the network is created for data exchange between several computers. At the same time, on users a certain share of responsibility that exchange is conducted including by the information protected by the copyright or violating rules of distribution (various options of kryak, keygen, patches and also serial numbers, emulators) lays down. So, by estimates of IC FINAM ^[1] the share of piracy products in the field of digital content (the software distribution kits and games, music, video, electronic cards and books) makes more than 95% and does not give in to calculation due to the lack of the exact estimates of amount of data extended through P2P networks. As a result, on the one hand, because of pirates, and on the other hand, because of still insufficient distribution of the Internet digital distribution concedes in Russia normal almost by 20 times. So, for example, according to the analysis of IFPI, 95% of music tracks in the world are downloaded illegally, and in Russia according to key players - 97-98%.