BitTorrent: The Protocol (1)

BitTorrent: It is a type of Peer to Peer network (P2P) which allows us to share files over the internet. Basically, it's a communication protocol. Bram Cohen created BitTorrent in 2001. Created for sharing large file files efficiently.

what is P2P??

P2P NETWORK

Peer to Peer is abbreviated as P2P. P2P is a decentralized platform. here 2 peers can directly contact each other without any need for a server. They can transfer information between each other without any third party.

basically, P2P communication between 2 parties without an intermediary. BitTorrent uses a P2P network for file sharing which is of any type of file like music, audio, video, etc.

How it BitTorrent works ??

BitTorrent clients are programs that implement the BitTorrent protocol. Users can join swarm to download upload files and can download files from each other simultaneously. BitTorrent clients can prepare, request, and transmit any type of file. BitTorrent files have “.torrent” as the file extension.

.torrent file is created by one of the users and then passed to another for downloading files content. This file consists of info such as what the file contains, data that is related to downloading. Trackers play the main role in the connection between users. (this will be discussed in deep in our series)

Basic concepts :

1. Seeder: Seeder is the one who has a complete file that you want to download from the network. basically, the seeder is an uploader.
2. Leecher: leecher is the one who wants to download the file. leechers download files from seeders. (Downloader).
3. Swarm: The swarms consist of all seeds and peers that are connected. if your client shows 100 seeds and 50 peers then the whole is your swarm.
4. .torrent: File extension for torrent files. It contains all info that you need to download a file.
5. Client: Program which loads .torrents file and implements BitTorrent protocol.
6. Indexer: Websites which list (index) .torrent files.
7. Chunks: Large file is broken down into smaller pieces. This piece is mainly 128kb,256kb,512kb, or 1Mb. also referred to as Piece.
8. Ratio: (data uploaded/data downloaded). Ratio ≥1.0 means you have uploaded more data than downloaded.
9. Health: The health of the torrent mainly depends on seeders. The health of torrent is kept healthy by people seeding as much as possible during downloading.
10. Peer: same as leechers. peer is the one instance in the client of the BitTorrent protocol.
11. Trackers: Trackers keep info about downloaders & uploaders of files. The tracker itself doesn't have any keep of files to share. trackers ensure that people connect.
12. Super-Seed: Super seeding is different from seeding. In seeding, the seeder sends the same piece to everyone while starting the seeding. while in super seeding seeder sends unique pieces to everyone. so that they then can swap those pieces.
13. Scrap: scarping is basically the client requesting info about the peers and most importantly progress.