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What is BitTorrent and how it works ?

Updated: Oct 19, 2022


Did You Know?


1. Programmer Bram Cohen, a University at Buffalo alumnus,[4] designed the protocol in April 2001, and released the first available version on 2 July 2001.


2. In February 2013, BitTorrent was responsible for 3.35% of all worldwide bandwidth—more than half of the 6% of total bandwidth dedicated to file sharing.


3. In 2019, BitTorrent was a dominant file sharing protocol and generated a substantial amount of Internet traffic, with 2.46% of downstream, and 27.58% of upstream traffic.


4. As of 2013, BitTorrent has 15–27 million concurrent users at any time.[12] As of January 2012, BitTorrent is utilized by 150 million active users. Based on this figure, the total number of monthly users may be estimated to more than a quarter of a billion (≈ 250 million).


5. BitTorrent consumes 12% of total Internet traffic in North America and 36% of total traffic in the Asia-Pacific region, according to a 2012 study. - Source Wikipedia.


What is BitTorrent?


BitTorrent is a communication protocol for peer-to-peer file sharing (P2P), which enables users to distribute data and files over the Internet in a distributed decentralized manner. To send or receive files, a person uses a BitTorrent client on their Internet-connected computer.


A BitTorrent client is a piece of software that uses the BitTorrent protocol. These clients are available for a variety of platforms and operating systems, including an official client released by BitTorrent, Inc. Popular clients include μTorrent, Xunlei Thunder, Transmission, qBittorrent, Vuze, Deluge, BitComet and Tixati.


How BitTorrent Works?


In general, when you download a web page, your computer connects to the Server (web server) and downloads the webpage or data directly from that web server. Each computer that downloads the data downloads it from the web page’s central server. This is how a normal website traffic works. So every time you are dependent on webpage hosting server bandwidth and speed.




In case of BitTorrent, It is a peer-to-peer protocol, which means that the computers in a BitTorrent swarm transfer data between each other without the need for a central server. In this scenario there is no centralized server.




Traditionally, when you download a .torrent file from webpage, that .torrent file contains a tracker. The BitTorrent client contacts a “tracker”. The tracker is a special server that keeps track of the connected computers with torrent clients. The tracker shares their IP addresses with other BitTorrent clients in the swarm, allowing them to connect to each other having same file which user wants to download.


Once connected, a BitTorrent client downloads bits of the files in the torrent in small pieces, downloading all the data it can get. Once the BitTorrent client has some data, it can then begin to upload that data to other BitTorrent clients in the swarm. In this way, everyone downloading a torrent is also uploading the same torrent. This speeds up everyone’s download speed. If lots of people are downloading the same file, it doesn’t put a lot of stress on a central server. Instead, each downloader contributes upload bandwidth to other downloaders, ensuring the torrent stays fast.



What are Leechers/ Peers, Seeders and swarm?






Leachers/ Peers : Users downloading from a BitTorrent swarm are commonly referred to as "leechers" or "peers". They are not having the full data and also who are sharing their bandwidth with others to upload the data for others.


Seeders : These are the users who has a complete copy of all the files in the torrent and uploading the files for others to download. Seeders must initially join the swarm so other users can download the data. If a torrent has no seeders, it won’t be possible to download. It means no connected user has the complete file.


Swarm : a group of computers downloading and uploading the same torrent.


How to torrent safely?


Torrenting can be risky without taking proper precautions. Downloading and uploading files through BitTorrent exposes you to a range of cyber threats. As mentioned above it shares your IP address to all other clients.