Exploring the Digital Domain

1
The Internet

• Chapter 18,
• Exploring the Digital Domain

2
In this chapter . . .
You will learn about

• 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 e-mail, ftp, telnet,
  and HTTP
• examining the future for the Internet

3
A Short History of the Internet

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

4
A Short History of the Internet

• 1987NSFNET backbone expands the Internet
  worldwide
• 1989CERN launches WWW project
• 1990ARPANET decommissioned
• 1992Internet Society formed
• 1993NCSA Mosaic GUI for WWW
• 1995NSFNET decomissioned
• 1998Government funds Internet2

5
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, e-mail addresses, etc.

6
How the Internet Works

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

7
How the Internet Works

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

8
Basic Internet Applications

• ELECTRONIC MAIL (EMAIL)asynchronous
  communications
• mail client
• mail server

9
Basic Internet Applications

• REMOTE LOGINS (TELNET)synchronous 2-way
  communications
• local host
• remote host

10
Basic Internet Applications

• FILE TRANSFER PROTOCOL (FTP)exchanging data and
  programs between systems
• anonymous ftp

11
Basic Internet Applications

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

12
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

13
Internet2

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

Abilene