Bit TorrentPresented By:Utsav Dholakia09BCE009

Guide:Prof. Tejal Upadhyay

CONTENTS What Is Bit Torrent ? Origin! Why Bit Torrent ? Torrent Terminology Facts

Introduction• Bittorrent is a Peer-to-Peer file sharing protocol.• One of the most common protocols for transferring

large files and accounts .• BitTorrent maximizes transfer speeds by breaking down

a large file into numerous small pieces and allows the recipient to download each tiny piece from different clients.

• The only objective of BitTorrent is to quickly give a copy of a single large file to a set of clients.

Origin• BitTorrent is creation of an American programmer Brahm

Cohen. • Cohen unveiled his idea at the first CodeCon conference.• Cohen wrote the first BitTorrent client implementation in

Python, and several other programs have since Implemented the protocol.

• Bittorrent is designed in April 2001 by Brahm Cohen and then maintained by Cohen’s company BitTorrent, Inc.

Why Bit Torrent ??

Traditional Client-server downloading

• Millions want to download the same popular huge files (for free)1.Softwares

2.Media (the real example!)• You open a Web page and click a link to download a file to your

computer.• The Web browser software on your computer (the client) tells

the server (a central computer that holds the Web pageand the file you want to download) to transfer a copy of the file to your computer.

• The transfer is handled by a protocol (a set of rules), such as FTP (File Transfer Protocol) or HTTP (Hypertext Transfer Protocol).

Router

“Interested” End-host

Source

Overloaded!

Disadvantages Of Client-Server Method

• Client-server model fails if• Single server fails or• Can’t afford to deploy enough servers

The BitTorrent (P2P)Protocol

• BitTorrent is a peer-to-peer file sharing protocol allowing users to distribute large amounts of data without putting the level of strain on their computers that would be needed for standard Internet hosting.

• Peer-to-peer file sharing is different from traditional file downloading. In peer-to-peer sharing, you use a software program (rather than your Web browser) to locate computers that have the file you want. Because these are ordinary computers like yours, as opposed to servers, they are called peers.

P2P PROTOCOLS

Advantages of P2P Method

• No central point of failure• E.g., the Internet and the Web do not have a central

point of failure.• Most internet and web services use the client-server

model (e.g. HTTP), so a specific service does have a central point of failure.

• Scalability• Since every peer is alike, it is possible to add more

peers to the system and scale to larger networks.

Disadvantages of P2P Computing

• Disadvantage of P2P Computing• Decentralized coordination. • All nodes are not created equal.

TERMINOLOGY

• Peers /Leechers– A node or computer that does not have the complete file

• Seed or seeder - A computer with a complete copy of a BitTorrent file

• Swarm - A group of computers simultaneously sending (uploading) or receiving (downloading) the same file

• .torrent - A pointer file that directs your computer to the file you want to download

• Tracker - A server that manages the BitTorrent file-transfer process

TERMINOLOGY• Share ratio – The ratio is the amount of data a user has

uploaded divided by the amount of data they have downloaded for a particular torrent (UL÷DL).

• Index – An index is, as the name implies, a searchable list of .torrent files, hosted on a website.

All peers act as a source

Peers exchange different pieces of the file with one another until they assemble a whole

As soon as the user has a piece of the file on his machine, he can become a source of that piece to other peers, helping speed download

Seed

A machine with a complete copy (the seed) can distribute incomplete pieces to multiple peers

FACTS

• BitTorrent is responsible for roughly 27-55% of all internet traffic and 45-78% of world’s P2P traffic all over the globe.

• As of 2011 BitTorrent has 100 million users and a greater share of network bandwidth than Netflix and Hulu combined.

• THE PIRATE BAY:Who in September,2008 had 6,912,029 visits & 2,140,240 UNIQUE VISITORS making it 109th most popular website on the internet.

• Another Popular torrent tracker ISOHUNT claims to have 9857 TERABYTES of files being shared.

References

• http://www.bittorrent.com • http://www.wikipedia.org/bittorrent • http://computer.howstuffworks.com/bittorrent.htm

Questions ??

THANK YOU