he network edge: r end systems(hosts) m run application programs m e.g., www, email at edge of network r client/server model m client host requests, receives service from server m e.g., WWw client browser)/ server, email client/server r peer-peer model m host interaction symmetric m e.g. Gnutella, KaZaA 1: Introduction 91: Introduction 9 The network edge: r end systems (hosts): m run application programs m e.g., WWW, email m at “edge of network” r client/server model m client host requests, receives service from server m e.g., WWW client (browser)/ server; email client/server r peer-peer model: m host interaction symmetric m e.g.: Gnutella, KaZaA