Torrent - The Basics

A .torrent file is a file that contains the basic information about a file or set of files. This includes the file names, sizes, the date created and some other information. The torrent file also contains an info hash – which is basically just a unique code for that torrent. No other set of file(s) will have the same info hash as this one. The final thing contained inside the torrent is a list of trackers. If you have some torrent files, you can’t open them in a text editor because they are encoded. You will need to open them in torrent client software.

A tracker is a computer on the Internet. The tracker’s role is to manage live torrent files and keep track of statistics. When you open a torrent file in your client software, your client software contacts the tracker specific to that torrent. You client tells the tracker how much of the actual files (described by the torrent) that you currently have.

A seeder is a person who has 100% of the files described by the torrent. If a torrent has no seeders, then no one (currently talking to the tracker) has anything to give.

A peer is a person who is looking for the files described by the torrent. The more peers the more people are actively looking for the files described by the torrent. A peer while downloading the file uploads it as well. When he finishes his download, he continues to upload it, thus becoming a seed.

A leech is a person who initially acts as a peer but after he finishes his download, leaves the swarm, freeing his part of bound bandwidth. Hence, if more and more people start to leech, older torrents will die out since there will be no seeds left.

A Bit Torrent client is any program that implements the Bit Torrent protocol. Each client is capable of preparing, requesting, and transmitting any type of computer over a network, using the protocol.

Working: To share a file or group of files, a user (seeder) first creates a small file called a “torrent” (e.g. MyFile.torrent). This file contains metadata about the files to be shared and about the tracker. Peers that want to download the file must first obtain a torrent file for it, and connect to the specified tracker, which tells them from which other peers to download the pieces of the file. Then the peer opens the file in a torrent client, which analyses the data stored in torrent file and downloads it from the seeder and other peer. Depending on number of seeds, and no of peers having data more than you, your download speed will be proportional. More the seeds and more the peers having more data, your download speed will be higher. But if no of peers become too high, then it causes a negative impact since there is more competition for bandwidth of seeds.

But torrent clients have this option which can limit the upload limits of data when they are acting as peers or seeds. Hence, some users misuse it to merely download and upload near nothing. Bittorrent network works on a principle of give and take, that is users who share more data while acting as peers or act as seeds once downloads complete are awarded with more download speed, while punishing those who don’t and lechers. But when a peer joins a swarm, he has no data, thus cannot seed. Hence, theoretically, he should be getting any data from seeds and other peers. But Bittorrent network has this feature of Optimistic Choking, which provides an initial bandwidth to new users, letting them download without uploading.

A few lines on downloading using torrents:

1. The first step is to download the torrent. They are available at sites of trackers. Eg, Pirate Bay, ISO hunt, Mininova, etc. Search in these sites for your required data.
2. When results turn up, choose the torrent that has maximum seeds and minimum peers, ie, greater seed/peer ratio. They help you attain more speeds. Also read comments, they are really helpful, avoiding embarrassment after having downloaded the data!
3. Having downloaded the torrent, you need a torrent client. I prefer utorrent, feature rich, light and zippy …. A good interface when compared to other clients, and equally feature rich. Compared to others like Azureus (now Vuze), it has simple settings, which can easily be tweaked. Download and install utorrent.
4. Open the Torrent file in utorrent, just double click on the file, it opens. It automatically starts downloading.
5. Depending on speed, torrent download finishes and it starts uploading itself. Do upload for a while, since there are a many users who now depend on you for the file. The more you upload, the more you get back in terms of speed. If everyone starts to leech, the torrent will die.

Scheduling torrent download tasks:

For the limited bandwidth plan users, it’s a curse to wake up late in night and start the download and again early in morning to stop it. Though utorrent comes with a scheduler, but off the happy hours, keeping utorrent active will cause long time seeding, also adding electricity bill if you keep your PC on, and waiting for happy hours.