P2P tutorial (ESEC 2001) Napster:System Architecture Central (virtual)database which holds an index of offered MP3/WMA files ● Clients(!)connect to this server,identify themselves(account)and send a list of MP3/WMA files they are sharing(C/S) Other clients can search the index and learn from which clients they can retrieve the file (P2P) Combination of client/server and P2P approaches First time users must register an account 2001 Karl Aberer,Manfred Hauswirth ESEC/FSE 2001 29 Napster:Communication Model Napster Server register (user,files)】 "Where is X.mp3?" "A has X.mp3” B Download X.mp3 2001 Karl Aberer,Manfred Hauswirth ESEC/FSE 2001 (c)2001 Karl Aberer,Manfred Hauswirth 15P2P tutorial (ESEC 2001) (c) 2001 Karl Aberer, Manfred Hauswirth 15 © 2001 Karl Aberer, Manfred Hauswirth ESEC/FSE 2001 29 Napster: System Architecture • Central (virtual) database which holds an index of offered MP3/WMA files • Clients(!) connect to this server, identify themselves (account) and send a list of MP3/WMA files they are sharing (C/S) • Other clients can search the index and learn from which clients they can retrieve the file (P2P) • Combination of client/server and P2P approaches • First time users must register an account © 2001 Karl Aberer, Manfred Hauswirth ESEC/FSE 2001 30 Napster: Communication Model A B Napster Server register (user, files) “Where is X.mp3?” “A has X.mp3” Download X.mp3