This document discusses peer-to-peer networks and the BitTorrent protocol. It describes how peer-to-peer networks allow clients to act as both servers and clients by sharing resources directly without a central server. It then explains key aspects of BitTorrent, including that it was created by Bram Cohen in 2003 as a P2P file transfer protocol for large file sharing where all users actively participate. The document also defines terms like torrent files, trackers, swarms, peers, leechers and seeders that are important components of how the BitTorrent protocol functions.

1. Peer-to-Peer Networks

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Client-Server Model
Central server store the files
Large traffic to the server will lead to
download failure.
Shortcomings of FTP makes
people to think over traditional
FTP.

3. •Network built and sustained by the
resources of each participant.
•Peers act as both client and server.
•Centralized/decentralized models.

4. Napster
• Gnutella (Bearshare, Limewire)
• Kademlia (Overnet, eDonkey)
• Fasttrack (Kazaa)
• Bit torrent
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Created by Bram Cohen
P2P(Peer To Peer) file transfer protocol
Transfer of large files
Files are shared by many users
Active participation of all users
Huge success in file sharing
domain since 2003

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This refers to the small metadata file you
receive from the web server (the one that
ends in .torrent)
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Metadata here means that the file contains
information about the data you want to
download, not the data itself.

9. WHAT DOES IT CONTAIN???
info: a dictionary that describes the file(s) of the torrent.
announce: contains the URL of the “tracker”.
creation date
Comments from the author (optional)
created by (optional)
piece length: number of bytes in each piece (integer).
pieces: string consisting of the concatenation of all 20byte SHA1 hash values, one per piece.
• private: (optional) is a field where the client requests to
avoid publicising it’s request.
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A peer is another computer on the internet that you
connect to and transfer data.
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They are similar to peers in that they won’t have the
complete file. But the main difference between the
two is that a leech will not upload once the file is
downloaded.
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A computer that has a complete copy of a certain
torrent. Once a client downloads a file completely, he
can continue to upload the file which is called as
seeding..

11. A server on the Internet that acts to coordinate
the action of BitTorrent clients.
The clients are in constant touch with this server
to know about the peers in the swarm.

12. The group of machines that are collectively
connected for a particular file.

22. Visualization

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First download a Torrent client to do us the job of
downloading the files
Then, go to a good Torrent search engine
Download the file with '.torrent' extension
Open it in your client
If the download starts with the progress bar
moving, take a deep breath!

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Deluge
Transmission
Ktorrent
Vuze
qBittorrent
Bittorrent
Bitcomet
µtorrent

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torrentz.com
piratebay.org
mininova.com
isohunt.com
extratorrent.com
kickass.to

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The BITTORENT protocol (the technology)
- No laws against file-sharing standards
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The BITTORENT client program
- Similarly, the client software does not do anything illegal
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*.TORRENT meta-files/trackers
- A grey area
• Content files
- It is illegal to download/upload copyright material.