If you use internet often then you might have come across the word ‘Torrent’. You might have also seen 'download via torrent' links while downloading a file from a webpage. What is Torrent and how it works? Let’s clear some basic concept about Torrent.
What is Torrent?
Torrent is file extension for BitTorrent file format. That being said what is BitTorrent now?
BitTorrent is a file sharing peer-to-peer protocol. Its main advantage is in fact that you not only download files from the original person who shared files but also get portions from fellow downloaders to maximize the data exchange.
BitTorrent is one of commonly used protocol for transferring large files as there is no centralized server hence the load gets distributed eventually. Before studying its working lets look at some common terms in torrents world.
How Torrent Works
When you traditionally download a file from web server, your computer connects to that web server and download the data directly from that server. Each computer which wants to download the files needs to connect to that specific web server to download the file.
Now BitTorrent is peer-to-peer protocol, which means instead of single centralized server a BitTorrent ‘swarm’(group of computer downloading and uploading data) transfers data between each other without needing a centralized sever.
Technically, a computer first loads a .torrent file into BitTorrent client and joins a BitTorrent swarm. The BitTorrent file contains tracker specified in loaded .torrent file. The tracker shares their IP addresses with other clients in swarm, allowing them to connect with each other.
Once connected, the client downloads files in small pieces. Once the client has some data, it can then begin uploading the data to other BitTorrent clients in swarm. In this way everyone is downloading as well as uploading the data.
This makes torrent unique. If suppose 20,000 people are downloading the same files it could have resulted in lots of load if we used one centralized server. But because of BitTorrent protocol each downloader now contributes upload bandwidth to other downloader's.
Common Terms Used in BitTorrent.
Number of users who have already downloaded the files and are currently uploading them. They have compete copy of the files.
A peer can be anyone who does not have entire file and is downloading as well as uploading file.
A leecher is someone who has downloaded or is downloading the file but is not uploading the file. Torrent clients have option to limit upload speeds so many users decrease their upload speed in comparison to downloading speed thus degrading the overall availability of file.
A tracker is a server that keeps tracks of which seeds and peers are currently in swarm (uploading or downloading the files).
Tracker helps in routing data from peers, initiating downloads and maintaining statics for system. Trackers routes ‘data’ or to be specific ‘packets’ to downloader.
Downloading Torrent File
For downloading Torrent file you would need a Torrent client. utorrent is popular torrent client out there. Just install any torrent client and whenever you want to download a file via torrent your browser will automatically open up your torrent client.
Torrent may be primarily used for piracy at present moment mainly because of its decentralized nature. However there are many legal uses of BitTorrent, like many Linux distros prefer torrent to push out updates as it reduces the stress on their servers.