Seminar on :Seminar on :

Seminar Guide :Prof. B.R. Bhamare

Presented By :Mayur V. Kathale

A Peer-to-peer Network System

OUTLINE• Introduction• Client-server System (Centralized)• Peer to peer network system

(Decentralized)• Comparisons• What is “ BitTorrent “?• BitTorrent components• The architecture of BitTorrent• Working• Advantages• Disadvantages• Conclusion• References

Introduction

• BitTorrent is created by Bram Cohen in 2001.

• It is peer to peer (P2P) file transferring system.

• It used to transfer very huge files.

• BitTorrent provides protocol to all torrent clients.

• This is most popular and efficient file transferring system.

• More efficient than client – server system.

Client – server Architecture

Client-server computing or networking is a distributed application architecture that partitions tasks or work loads between service providers (servers) and service requesters, called clients.

Client – server working

• Client send GET message to server• Server send files• Transfer is handled by FTP and HTTP.

Client – server disadvantages

• Traffic congestion.• Crashes whole system when server fails.

Peer to peer Architecture

Peertracker

• Each peer directly connected to other peer.• It is used for large file transfer.• peer uploads data while downloading any file.

Peer to peer Architecture

• File to be transfer is divided into equal size of pieces.

• These pieces are downloaded from different peers parallely.

components

• BitTorrent Client Software• .torrent file or METAinfo file• Leechers • Peers• Seeds• Tracker• Piece (of a file)• Data• Torrent index server

Torrent Client software• Client S/W – program which sits on a peers computer and implements the protocol [BitTorrent].• Reads .torrent file

It controls all operations such as :• reads information contents in .torrent file.• After reading .torrent file it sends message to tracker to send list of peer.• connects to peers.• Keeps all record of the file which is receiving.

Torrent Client software

Torrent File / Metafile

• It has extension as .torrent• It is extremely small ( up to 100KB )• It is downloaded from torrent index server

• contains the information that points to the actual file and the people who are sharing it.

Contents of .torrent file –• Info size of piece total no. piece SHA number• announce• creation date• comment• created by

Torrent File / Metafile (contd.)

seeds

• These are the clients who has entire file• They uploads files to other peers

• This is the peer which does not have entire file

• They uploads part of file at same time when they downloads other part.

Leecher

peers

• It is the client which is responsible for file transfer

• Downloading speed of any file using torrent depends on number of peers.

• Peers = leech + seed

Piece(of a file)

• The file which to be download is divided similar size of pieces.

• These pieces are downloaded parallel • Each pieces is download from different peers

1 2 3 4 5 6 7 8

Tracker

• Tracker is the server• It contains all database about peers of a torrent• It provides all list of peers which are associated with

a particular torrent• These trackers are mentioned in the Metafile• Client S/W sends request to send list of peers• connects to all peers

Torrent index website

• Source of .torrent files• Torrent search engine

Workingtracker: tracks peers in torrent; providestracker list

torrent: group of peers exchanging chunks of a file

trading chunks

peertorrent index server: search for torrents;provides .torrent file

.torrent

advantages• BitTorrent is an open-source program offers a

spyware- and nuisance-free installation. • Allows users to share large amounts of data in a

short span of time.• Discourages “freeloading” by rewarding fastest

uploaders.• The more popular a file is — the more people want a

copy of it — the faster it can be downloaded, because there are more places to get pieces of it.

conclusion

•. BitTorrent is a great protocol to distribute large files.

• Bit Torrent was conceived as a way of distributing large file more quickly, efficiently, and reliably.

• BitTorrent is a peer –to-peer file sharing system that is quickly becoming the method of choice for publishing and sharing large files across the internet

references

• http://www.ccs.neu.edu

• http://www.bittorrent.org

• http://radar.oreilly.com

• http://in.tech.yahoo.com

Now Yours Time !!! ?