P2P WeeSan Lee

What is a client-server model? GET rfc1855.txt Web Server Client 1Client 2 rfc1855.txt

What is a peer-to-peer model? Web Server Client 1Client 2 rfc1855.txt

What is a peer-to-peer model? Host 3 Host 1Host 2 rfc1855.txt GET rfc1855.txt rfc1855.txt GET rfc1855.txt

What is a peer-to-peer model? There is no server nor client, only peers In fact, each peer is both server and client

P2P Network An overlay network that employs P2P model For example  Napster  KaZaA  Gnutella  BitTorrent

P2P Network - Napster A centralized P2P network  Centralized index server Created by Shawn Fanning from Northeastern University in 1999 A centralized way to look for mp3 music instead of from IRCs or newsgroups Later sued by RIAA (Recording Industry Association of America) and shutdown in 2001

P2P Network - KaZaA A semi-centralized P2P network Created by Niklas Zennström and Janus Friis  Whom later founded Skypes in 2003 Like Napster, KaZaA had been sued by music record companies

P2P Network - Gnutella A pure, unstructured P2P network All peers act as equals  No centralized server Still need a way to bootstrap though Software  LimeWire Pros  No single point of failure Cons  Could be very slow Solution: Ultra Peers

P2P Network - BitTorrent A P2P file sharing communications protocol for large files such as movies, TV shows, etc Created by Bram Cohen in 2001 Software  ABC  Azureus  BitComet  BitLord  BitTorrent  Opera  μTorrent

P2P Network - BitTorrent Torrent file  A small file contains the information of the file or a group of files (also called torrent) one would like to share, and the trackers  Usually with.torrent extension Tracker  A computer that tells the downloaders where to download the files

P2P Network - BitTorrent Seeder  A peer that has completed copy of the torrent Leecher  A peer that does not have completed copy of the torrent Swarm  All peers sharing a torrent are called a swarm

P2P Network - BitTorrent Torrent Search Engines  Mininova  TorrentSpy  Isohunt

Beside File Sharing Bioinformatics  P2P networks are used to run large programs to find cure Academic Search Engine  Free and open search engine for scientific knowledge Education and Academic  Share academic content

Beside File Sharing (cont) Business  Content distribution Software TV shows Telecommunication  Skype

Attacks on P2P Network Poisoning  Provide different contents Polluting  Provide bad data

A Few Final Words Engaging P2P file sharing on UC campuses is prohibited From  “When you go online and download songs without permission, you are stealing.”  “Pay a little now or a lot more later.”  “Anyone – and everyone – engaged in music theft is at risk for a lawsuit.”

A Few Final Words (cont) From  Criminal penalties for first-time offenders can be as high as five years in prison and $250,000 in fines.  Civil penalties can run into many thousands of dollars in damages and legal fees. The minimum penalty is $750 per song.

References Internet Effectively  Ch 13 - The Internet’s Impact on Traditional Media Peer-to-peer  BitTorrent  RIAA FAQ 

Homework 9 Read “Is Someone Tracking P2P Users?” by A. Banerjee, M. Faloutsos and L. Bhuyan  networking07.pdf networking07.pdf  Best Paper Award at IFIP Networking 2007 Post your comments on Homework 9 Forum