The Start of Digital Anarchy Shawn Fanning (19-yr-old student nicknamed Napster) developed the original Napster application and service in January 1999 while a freshman at Northeastern University –Share MP3 files with peers around the world Next version: launched in May 1999, by Shawn Fanning (19 -yr-old student nicknamed Napster ) and Sean Parker (20) Allowed Users to MP3 Files - compression format, good quality but 1/12 th original size –Napster.com: p2p MP3 exchange service November 2000 – Napster has 38 Million members 40 million users in first 18 months At peak,70 million users 1.57 million simultaneous users

What is Napster Indeed? Napster is sometimes referred to as a p2p network –This is not quite true Napster ran a central server –You connected to that server and announced what files you had to share. Every search was conducted on the dataset assembled at the central server Connections to download files where done between peer machines only!

Concept of Napster Napster used centralized servers to keep a catalog of available files 1. User sends out request Napster searches central database Search request 2. The central server sends back a list of available files for download Search response Napster server user 3. Requesting user downloads the file directly from another Napster user computer Download from user

Importance of Napster The P2P revolution is started. Central indexing and searching service File downloading in a peer-to-peer point-to- point manner. Napster user B (Client + Server) Napster index Association Napster user A (Client + Server)

How Napster used to work It is first necessary to download and install Napster software and to sign up for a free account at Napster By clicking the Napster icon, a connection is established with Napster Web site, where the name of the music searched can be entered in a search window The Napster software tracks all users who are online at that particular time and provides access to tracks stored on users' hard drives When the song requested is found, Napster establishes a connection between the two computers so that it could be downloaded Four steps: Connect to Napster server Upload your list of files (push) to server. Give server keywords to search the full list with. Select “best” of correct answers. (pings)

Directory Server User Description of the Architecture A central directory server maintain index on the metadata of all the files in the network. The metadata might include file names, creation dates, and copyright information. The server also maintain a table of user connection information including user’s IP address and line speed. A file query is sent to the server first. A query consists of a list of desired words. When the server receives a query, it searches for matches in its index The query results including a list of users who hold the file are sent back to the user who initiated the query The user then opens a direct connection with the peer that has the requested file for downloading

Napster A way to share music files with others Users upload their list of files to Napster server You send queries to Napster server for files of interest –Keyword search (artist, song, album, bitrate, etc.) Napster server replies with IP address of users with matching files You connect directly to user A to download file

Overview of the P2P File Sharing Solutions

Client-Server File Sharing Server(s) perform all file sharing tasks –All files stored on server(s) –All queries regarding file availability addressed by server(s) –All files transmitted from server(s) Therefore, server(s) constrain performance –Can only hold as many files fit in server storage –Query response time dictated by server speed –Files transmitted over server network connection with limited capacity

Client-Server File Sharing The MP3.com Architecture MP3.com Machine A 1. Have any Metallica songs? 3. Please send one 2. Yes 4. Here it is Note: A few years ago, a band called Metallica sued the file sharing service Napster for allowing illegal music exchange over it’s network.

Peer-to-Peer File Sharing At least some tasks are distributed among peers: –Files stored on and transmitted from peer hosts –Queries regarding file availability addressed by peer hosts Distributed tasks are not limited by server performance –Network can hold as much as can be stored on all peers –Transmission costs shared by all peers –Each peer contributes to responding to queries For example, –Napster distributed file storage and transmission –File availability was centralized

Peer-to-Peer File Sharing In Action Interacting Messages –Ping: “Are you there?”: Directed at a Peer –Pong: “Yes, I am here” –Query: “I am looking for 007 posters” –Query Response: “I have the poster. Download from xxx.xxx.xxx.xxx:xx All these messages are forwarded from a Peer to its neighbors

Main Server File List: UserC song.mp3 UserD another.mp3 ….. User A 2. User A searches for song.mp3 User C (Song.mp3) 1. Construct Database Users connect to Napster Server Server builds up a list of available songs and locations User D (Another.mp3) User B … 3. Server searches database. Finds song on User C’s machine 4. Server informs User A of the location of song.mp3 5. User A connects to User C and downloads song.mp3 Brokered/ Hybrid P2P File Sharing with Napster

Broker Mediated File Sharing Model Users register files with a broker for sharing use broker to find files to copy Broker BobCarol Where is “X-File Season 7”? Carol has it Copying X-File Season 7

Centralized Napster model Benefits: –Efficient search –Limited bandwidth usage –No per-node state Drawbacks: –Central point of failure –Limited scale BobAlice JaneJudy Resource Discovery

Advantages and Disadvantages of Centralized Indexing Advantages: –Locates files quickly and efficiently (more effective) –Searches are as comprehensive as possible –All users must registered to be on the network Access is controlled Disadvantages: –Vulnerable to censorship and technical failure System has single points of entry; one fails could bring whole system down –Popular data become less accessible because of the load of the requests on a central server –Central index might be out of data because the central server’s database is only refreshed periodically Resource Discovery

napster.com users File list is uploaded 1. A Simple Example

napster.com user Request and results User requests search at server. 2. A Simple Example

napster.com user pings User pings hosts that apparently have data. Looks for best transfer rate. 3. A Simple Example

napster.com user Retrieves file User retrieves file 4.

Summary of the Features Central Napster server –Can ensure correct results –Bottleneck for scalability –Single point of failure –Susceptible to denial of service Malicious users Lawsuits, legislation Search is centralized File transfer is direct (peer-to-peer)

Screenshots – Napster Searching …

Screenshots – Napster Downloading ….

Benefits and Drawbacks of the Napster Model Benefits: –Efficient search –Limited bandwidth usage –No per-node state Drawbacks: –Central point of failure –Limited scale BobAlice JaneJudy

Traffic Generated by Napster 3/00: 25% UWisc traffic Napster 2000: est. 60M users 7/01: # simultaneous online users: Napster 160K Gnutella: 40K Morpheus: 300K Approximately 10,000 music files were shared per second using Napster, and every second more than 100 users attempted to connect to the system and there will be 75 million Napster users by the end of 2000 A “disruptive” application/technology?…

Reported Bandwidth of Napster

End of Napster 12/99: first lawsuit April 2000 – Metallica starts law suit – Huge and long court case July 2001 – Napster ordered offline, June 2002 bankrupt 2/01: US Circuit Court of Appeals: Napster knew users violating copyright laws After the Recording Industry Association of America sued Napster for copyright infringements, the court ruled that Napster was indeed violating copyrights and it is shut down

End of Napster (Cont.) Napster argued since it was only involved in collecting the information about files available, it was legal. Napster never shared any illegal file. The courts thought otherwise. It was shut down. Napster network died without a central machine. To enable true piracy, we need a truly distributed system.

Last minute humor Steve Sack, Minnesota, The Minneapolis Star-Tribune

Epilogue 1999: Napster is born 2002: Napster is gone… April 30, 2002: A new study from WebSense indicates that the number of file- swapping, and peer-to-peer websites, has grown by 535 percent in 2001, despite legal efforts to have them shut down According to the study findings, the number of p2p websites totals nearly 38,000 universities notice first mid-01: shut down service; other apps emerge since 00