What is a P2P network?

P2P is an abbreviation for the English expression "Peer-to-peer", which can be translated as "peer to peer". They are also called peer-to-peer, decentralized or peer-to-peer networks.

What is the difference between a P2P network and a regular file sharing service? In the case of a file sharing service, all data is stored on a server from which users can download them. If the file is deleted from the server or serverbecomes for some reason unavailable, access to this information from users, of course, will no longer be. In addition, the download speed is limited by the bandwidth of the server and the load on it.

There is no such server in the P2P network. Required files are stored on users' computers in "shared folders" (folders that are open for public access). And each computer can act as a client (download information), and as a server (give information). A file with this one can swing fragments from several sources at once. This allows you to increase the download speed.

Now most often used are the so-called hybrid (partially decentralized) P2P networks. In such networks, the server is present, but itIt is used not for storing information, but for coordinating the work of the network. This network combines the speed of a pure P2P network and the reliability of a centralized network. At the moment, the two most popular peer-to-peer network protocols used in P2P networks are BitTorrent and Direct Connect.

P2P networks: the BitTorrent protocol

When exchanging files using the BitTorrent protocol downloaded files are transmitted in parts. Downloading a file with a special program (torrent-client), you at the same time give it to other customers on the principle of "you to me - I to you."

To coordinate the exchange of files there is a dedicated server - a torrent tracker. It is needed in order for the feasts (participants in the network)could find each other. Usually the tracker stores hash-sums (file identifiers), IP-addresses and incoming client ports. But often the torrent tracker is also a site with information about the distributed files (descriptions, metadata, etc.) and the number of peers, download statistics.

On some trackers, in order to comply with the basic principle of the P2P network ("you to me - I to you"), there is rating system. The ratio of information downloaded andgiven by the user. If the amount of downloaded information is much higher than the amount of information that was downloaded, the rating will be low, and the downloadability for the user will be limited.

Most popular torrent clients Is the official client of BitTorrent, uTorrent, BitComet, KTorrent, Deluge, Transmission, Vuze (Azureus) and others.

P2P networks: Direct Connect protocol

The Direct Connect protocol is more often used in local networks. For download in DC network you need to installspecial client and connect to one or more DC-hubs. In this P2P network, the hub acts as a server. By connecting to it, you will see a list of connected users, you can search for shared files and, of course, download them.

Files are searched by hash-sum, so Even if the file is renamed, it does not affect its upload in any way (in the case of torrents, renaming a file causes the system to stop seeing it). Files, again, can swing from several sources at once.

In addition, DC hubs usually have common chat and instant messaging, so that the DC client can be used not only to exchange files, but also to communicate with other users of the P2P network.

The most popular DC clients Are different descendants of the DC ++ client, in particular, StrongDC ++, ApexDC ++, FlylinkDC ++, Greylink, EiskaltDC ++, etc.

P2P networks - a fairly convenient way to share files. But, alas, in such networks it is almost impossible to track copyright infringement, because files are kept by all and at the same time, in fact, no one else. Distribution of files - exclusively on the conscience of P2P network members.