Chapter 18, Exploring the Digital Domain The Internet

In this chapter... how the Internet evolved from an experimental network in the 1970s how your computer can communicate across the world with other computers over a span of diverse interconnected networks how Internet applications are based on client/server architecture basic Internet applications: , ftp, telnet, and HTTP examining the future for the Internet You will learn about

A Short History of the Internet 1964—Paul Baran (RAND Corp.) proposes a loosely-coupled, robust network 1969—ARPANET formed as a four-node network (UCLA, SRI, UCSB, and U of Utah-Salt Lake City) 1974—Kahn and Cerf head TCP/IP project 1980—CSNET added to ARPANET 1986—NSF forms NSFNET 1964—Paul Baran (RAND Corp.) proposes a loosely-coupled, robust network 1969—ARPANET formed as a four-node network (UCLA, SRI, UCSB, and U of Utah-Salt Lake City) 1974—Kahn and Cerf head TCP/IP project 1980—CSNET added to ARPANET 1986—NSF forms NSFNET

A Short History of the Internet 1987—NSFNET “backbone” expands the Internet worldwide 1989—CERN launches WWW project 1990—ARPANET decommissioned 1992—Internet Society formed 1993—NCSA Mosaic GUI for WWW 1995—NSFNET decomissioned 1998—Government funds Internet2 1987—NSFNET “backbone” expands the Internet worldwide 1989—CERN launches WWW project 1990—ARPANET decommissioned 1992—Internet Society formed 1993—NCSA Mosaic GUI for WWW 1995—NSFNET decomissioned 1998—Government funds Internet2

How the Internet Works DATAGRAMs are packets of data that also contain addressing information TCP/IP define protocols (standards) for how datagrams are packaged and delivered IP address is a number that signifies the address of an Internet host Domain names are pseudonyms for IP addresses Domain name system servers provide user with IP numbers for URLs, addresses, etc. DATAGRAMs are packets of data that also contain addressing information TCP/IP define protocols (standards) for how datagrams are packaged and delivered IP address is a number that signifies the address of an Internet host Domain names are pseudonyms for IP addresses Domain name system servers provide user with IP numbers for URLs, addresses, etc.

How the Internet Works Gateways and Routers transmit datagrams across the Internet Client/Server applications add functionality to the Internet Gateways and Routers transmit datagrams across the Internet Client/Server applications add functionality to the Internet

How the Internet Works IP (Internet Protocol) how datagrams are routed across the network TCP and UDP how messages are delivered TCP -- guaranteed service ( , HTTP, etc.) UDP -- normal service (PING, DNS, etc.)

Basic Internet Applications ELECTRONIC MAIL ( ) asynchronous communications mail client mail server ELECTRONIC MAIL ( ) asynchronous communications mail client mail server

Basic Internet Applications REMOTE LOGINS (TELNET)—synchronous 2-way communications local host remote host REMOTE LOGINS (TELNET)—synchronous 2-way communications local host remote host

Basic Internet Applications FILE TRANSFER PROTOCOL (FTP)—exchanging data and programs between systems anonymous ftp FILE TRANSFER PROTOCOL (FTP)—exchanging data and programs between systems anonymous ftp

Basic Internet Applications HTTP (HyperText Transfer Protocol) cookies ID used for identifying users, transactions, etc. Web caching client-side server-side -- proxy servers

Internet2 consortium of government, industry, and education establish network capabilities to support national research develop the next generation of Internet applications transfer these to worldwide Internet

Internet2 remote instrumentation and virtual laboratories distance learning digital libraries Tele-immersion multicasting Abilene