CS155b: E-CommerceNapster Client-Server InteractionNotes on Client-Server InteractionNapster Client-Client (P2P) InteractionNapster HistoryNapster History, continuedSlide 7Gnutella P2P File Sharing“A” Generates a Gnutella Request“B” Receives Gnutella Request (A, S, N, T)Gnutella Advantages and DisadvantagesSlide 12Gnutella HistoryGnutella ClientsSlide 15LimeWire’s Business StrategyKazaaKazaa File SharingFreenet P2P File SharingHomework for February 11Internet Radio and You:Four things needed to webcast:How does a webcast work?Intro to Radio LicensingLicensing Webcast RadioWhat were these new license fees?How were these new rates determined?Uproar among small-business webcastersHR 5469: Small Webcasters Support ActThe Future of Net Radio?The Future of Net Radio? cont’dAcknowledgmentsCS155b: E-CommerceLecture 8: Feb. 6, 2003Peer-to-Peer File Sharingand Internet MusicNapster Client-Server Interaction Client1MP3-file1MP3-file2MP3-filenSearches a db of currently onlineusers for one that has previously stored therequested MP3.Adds client1 and its list to db.Removes client1 and its list from dbhelloackClient1’s IP addressNames of MP3s on Client1’s MachineRequestIP address of online user(client2) who has requested file [repeat]goodbyeackNotes 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 business?Napster Client-Client (P2P) InteractionClient1Client2Client1’s IP address Request Requested MP3Note: This part uses “standard Internet protocols,” e.g., FTPNapster 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 aGnutella 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 DisadvantagesMain 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 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 file-sharing client available for free download. The application displays an ad banner.•Design goal: Achieve Napster-like efficiency and avoid Napster-like liability.KazaaKazaa 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
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