L4.sp11 - 1 Indranil Gupta (Indy) Lecture 4 Peer to Peer...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 Indranil Gupta (Indy) Lecture 4 Peer to Peer Systems January 27, 2011 All Slides © IG CS 525 Advanced Distributed Systems Spring 2011 2 D.S. Theory Peer to peer systems Cloud Computing Sensor Networks 3 4 A Brief History • [6/99] Shawn Fanning (freshman Northeastern U.) releases Napster online music service • [12/99] RIAA sues Napster, asking $100K per download • [3/00] 25% UWisc traffic Napster, many universities ban it • [00] 60M users • [2/01] US Federal Appeals Court: users violating copyright laws, Napster is abetting this • [9/01] Napster decides to run paid service, pay % to songwriters and music companies • [Today] Napster protocol is open, people free to develop opennap clients and servers http://opennap.sourceforge.net 5 Napster Structure S S S P P P P P P Client machines (“Peers”) napster.com Servers Store their own files Store a directory, i.e., filenames with peer pointers Filename Info about PennyLane.mp3 Beatles, @ 128.84.92.23:1006 ….. 6 Napster Operations Client • Connect to a Napster server • Upload list of music files that you want to share – Server maintains list of <filename, ip_address, portnum> tuples. Server stores no files. • Search – Send server keywords to search with – (Server searches its list with the keywords) – Server returns a list of hosts - <ip_address, portnum> tuples - to client – Client pings each host in the list to find transfer rates – Client fetches file from best host • All communication uses TCP 7 Napster Search S S S P P P P P P Peers napster.com Servers Store their own files Store peer pointers for all files 3. Response 1. Query 2. All servers search their lists (ternary tree algo.) 4. ping candidates 5. download from best host 8 Problems • Centralized server a source of congestion • Centralized server single point of failure • No security: plaintext messages and passwds • napster.com declared to be responsible for users’ copyright violation – “Indirect infringement” 9 Gnutella • Eliminate the servers • Client machines search and retrieve amongst themselves • Clients act as servers too, called servents • [3/00] release by AOL, immediately withdrawn, but 88K users by 3/03 • Original design underwent several modifications http://www.limewire.com 10 Gnutella P P P P P P Servents (“Peers”) P Connected in an...
View Full Document

This note was uploaded on 12/08/2011 for the course CS 525 taught by Professor Gupta during the Spring '08 term at University of Illinois, Urbana Champaign.

Page1 / 33

L4.sp11 - 1 Indranil Gupta (Indy) Lecture 4 Peer to Peer...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online