You have certainly heard of BitTorrent or the torrent, I though I realize that the less experienced often do not understand what it is seen that the operation is slightly different from that of the famous Emule and other programs that use the technology Peer to Peer for file sharing, so in this article I will try to explain in a simple way the concepts on which the BitTorrent protocol is based.
BitTorrent is precisely a Peer to Peer protocol that allows the distribution and sharing of files via the Internet, the original files you want to share are broken up into many small fragments that will be sent to those who request them, once everyone the fragments of a file are downloaded, the file is recomposed in the recipient’s computer.
The advantage is that in this way it is possible to download the file fragments that we need from multiple sources, fragments that we, in turn, are obliged to send to those who need them.
The main entities involved are basically 5
The Peers: They are those who are downloading a file but have not downloaded it completely, the peers share the fragments of that file they currently have.
Seed: They are those who have spread the original file or who have managed to download it completely, the seeds are very important as only they can provide information on all the fragments that make up that file and of course only they have all the fragments.
The Tracker: A central server that plays the role of “traffic policeman”, the tracker, in fact, coordinates the requests of users who are trying to download files and provides information on who has the fragments they need, The Tracker does not contain the files that are shared and the files do not pass through him.
The .torrent files: They are small files with the extension .torrent that do not contain the file to download but only information about it, such as for example all the fragments in which the original file was divided or the address of the Tracker to contact. To download any file via BitTorrent it is always necessary to obtain this file, to find them you need to use a specific search engine.
BitTorrent Client: it is a program installed on the user’s computer that allows files to be downloaded using the BitTorrent protocol, to start downloading a file this program needs its .torrent file. There are several clients and they are all free, I recommend Utorrent.
In practice, simplifying the concept to the maximum when a user decides to download a file, the tracker is contacted to indicate who to download the fragments of the file, as each fragment is downloaded is also shared with others, when all the fragments are downloaded the file is recomposed and automatically that user is a Seed of that file.
The main practical difference between BitTorrent and the other Peer to Peer programs lies in the fact that the file to be downloaded should not be searched for in the program with which the file is downloaded, but rather to search the web and download a small .torrent file that represents the file to be downloaded, the .torrent file will then be opened with the client installed on the computer and the download will begin.
One of the main advantages of BitTorrent compared to Emule is the high speed at which it is possible to download large files, the download speed for a file with different sources can reach 150KB / s, improbable speeds for Emule, however for the moment the latter makes a greater number of files available, thus increasing the probability of finding what we need.