CS155b E Commerce Lecture 8 Feb 6 2003 Peer to Peer File Sharing and Internet Music Napster Client Server Interaction Client1 hello ack Client1 s IP address Names of MP3s on Client1 s Machine Request MP3 file1 MP3 file2 IP address of online user MP3 filen client2 who has requested file repeat goodbye ack Searches a db of currently online users for one that has previously stored the requested MP3 Adds client1 and its list to db Removes client1 and its list from db Notes on Client Server Interaction Proprietary protocol and db search No MP3 files stored on server Don t need usernames Could have made the service anonymous No need to save IP addresses between sessions Many are assigned dynamically Discussion point Are anonymity and memorylessness threats or opportunities for Napster Client Client P2P Interaction Client2 Client1 Client1 s IP address Request Requested MP3 Note This part uses standard Internet protocols e g FTP Napster History 1987 MP3 format developed by Karlheinz Brandenburg of Fraunhofer Gesellschaft CD ripping now feasible 1999 Shawn Fanning develops Napster believing he has bypassed copyright law Napster has 25M users in its first year Dec 1999 RIAA sues Napster for contributory and vicarious copyright infringement April 2000 Metallica sues Napster Yale Indiana Univ and USC Yale bans the use of Napster within a week Napster History continued July 2000 US District Judge Patel grants RIAA s request for an injunction The injunction is temporarily stayed soon thereafter October 2000 Napster announces a partnership with Bertlesmann AG one of the major labels in the industry whose trade association is suing it January 2001 Napster and Bertlesmann say that they will roll out a subscription service by early summer and will use DRM technology Napster History continued February 2001 Ninth Circuit upholds lower court s findings that Napster is guilty of contributory and vicarious infringement Summer 2001 Napster and Bertelsmann fail to roll out subscription service September 2001 Napster reaches a settlement with music publishers but not with RIAA record labels However CNET com reports the number of users has dropped from tens of millions to almost zero Napster R I P Gnutella P2P File Sharing Pure Peer to Peer Peers communicate over standard HTTP Goal is total decentralization In particular no Napster like server that directs traffic collects data and otherwise centralizes control A Generates a Gnutella Request Creates Search String S Unique Request ID N Time to Live T Sends A S N T to all of its Gnutella neighbors B Receives Gnutella Request A S N T If B has already received request N or T 0 B drops this request and does nothing B looks up S in its local file system and sends N Result to A B sends B S N T 1 to all of its Gnutella neighbors and it records the fact that A has made the request N When B receives a response of the form N Result from one of its neighbors it forwards this response to A Gnutella Advantages and Disadvantages Main Advantage Search for S can be done in many ways e g structured database search simple text matching fuzzy text matching etc Result can take many forms Main Disadvantage Inefficiency Flood of Requests If average number of neighbors is C and average TTL is D each search can cause CD request messages Natural evolution into many barely connected subnets not one user community Other Disadvantage Request monitoring Comes with standard HTTP Gnutella History Gnutella was written by Justin Frankel the 21 year old founder of Nullsoft Nullsoft maker of WinAmp posted Gnutella on the Web March 1999 Nullsoft acquired by AOL June 1999 A day later AOL yanked Gnutella at the bequest of Time Warner People had already downloaded and shared the program Gnutella continues today run by independent programmers Gnutella Clients LimeWire XoloX Morpheus Phex Shareaza and many others developed by companies and individuals LimeWire LLC is a wholly owned subsidiary of the Lime Group a technology incubator that owns several small innovative companies LimeWire provides a Java based Gnutella client This allows the software to run on multiple platforms with a consistent interface LimeWire s Business Strategy Distribute its software as the best file sharing client available Take advantage of the Gnutella network 73000 hosts Improve and enhance interface Reach more users by supporting multiple platforms Give away a free ad supported version sell an ad free enhanced version for a small price Charge companies for advertisements and provide partner links on website Kazaa Kazaa Media Desktop is produced by Sharman Networks Ltd a consortium of private investors with multimedia interests see company website Based in Australia with offices in Europe Kazaa Media Desktop is a Windows filesharing client available for free download The application displays an ad banner Design goal Achieve Napster like efficiency and avoid Napster like liability Kazaa File Sharing Peers connect directly to each other content is distributed and there is no central server Search requests are sent to the nearest supernode which tries to locate the content if it fails the request is sent to other supernodes Any node running Kazaa with a good Internet connection can become a supernode Other Kazaa users upload lists of shared files to neighboring supernodes Supernodes facilitate search but do not host content peers connect directly to download files Supernode status is controlled by the software based on user settings permission to become a supernode bandwidth restrictions etc Freenet P2P File Sharing Works similarly to Gnutella Exceptions include Intermediaries store all results Diffuses responsibility Uses proprietary protocol Eliminates HTTP monitorability Launched by Ian Clarke Univ of Edinburgh in 1997 Explicitly anti censorship anti copyright and pro anonymity in its goals Less popular and less developed although certain clients exist see http freeweb sourceforge net for a FreeNet 0 4 client Homework for February 11 Read chapter 5 of the textbook Key Management is Trust Management Internet Radio and You Why New Digital Copyright Legislation Matters A CPSC 155b Presentation by Kat Kunz Four things needed to webcast Audio files mp3 wav etc Streaming media software e g shareware professional software by RealNetworks High speed Internet connection Webcasting server to re route the stream to the rest of the web How does a webcast work After a streaming object e g specific song or movie is selected it is