Understanding the Internet and the World Wide Web

1. Agenda • The Internet and the WWW • what’s the difference anyway? • History of The Internet • IP Addresses, URLs & Domain Names • READ Zeid: page 3-20

2. The Internet vs. World Wide Web • What EXACTLY is the difference between the Internet and the World Wide Web? • Why is it important to know the difference?

3. The Internet • Computers can be connected in a variety of different ways. • Ethernet, Token-ring, Wireless, Ports (Serial, Parallel, USB). These are all communication subtrates. • Two or more connected computers form a Network • The CS Dept. has its own Ethernet Network • Different types of networks can be connected • via bridges, gateways, etc.

4. The Internet • Two or more connected networks can be called an inter-network • Inter-networks can obviously be connected • At some point in history, inter-networks became connected across the entire USA • Eventually, inter-networks became connected across the entire world • The entire world-wide collection of connected networks became known as The Internet.

5. The Internet Most experts in the “Network World” think of The Internet as both • The physical infrastructure (wires, routers, hubs, switches, satellites, optical cables, receivers, transmitters, etc.) that form the inter-connections. • And, the actual collection of computers (and devices) that are “inter-connected.”

6. The World Wide Web (WWW) • Most experts think of The WWW as • data that is accessible via a URL • (narrow definition) • All the data and services that are widely available via The Internet • (general definition)

7. The World Wide Web (WWW) • Thus, The Internet is the physical hardware that makes the connections possible and • The World Wide Web is the content and services that are widely available over this massive collection of connected computers. • Important Note: • Some companies use the Internet to share information, but this information is only accessible through proprietary protocols, • Since, it is NOT widely available, it is not really part of the WWW.

8. The World Wide Web (WWW) • While the two terms are somewhat synonymous to the non-expert, • You should be aware of the difference between The Internet and the WWW Internet WWW

9. Internet Jargon • In the field of Network Communications there are thousands of terms, most of which are acronyms and are not found in standard dictionaries. • The following website is good for reference: • http://www.webopaedia.com

10. The World Wide Web (WWW) Examples: Content & High-level Protocols • Content: WebPages • Hypertext Transfer Protocol (http) • URL (Universal Resource Locator) • Content: Data Files & Programs • File Transfer Protocol (ftp) • Content: Music & Videos • Gnutella Protocol

11. The World Wide Web (WWW) More examples • Content: Email • SMTP (Simple Mail Transport Protocol) • IMAP (Internet Message Access Protocol) • POP (Post-Office Protocol) • DNS (Domain Name System) • MIME (Multipurpose Internet Mail Extensions) • Content: Peer to Peer messaging • AOL IM Protocol • MSN Messenger Protocol

12. The Internet Examples: Hardware & Low-Level Protocols • Hardware • Computer, Ethernet card • Communication Substrate:CAT-5 cable, fiber optic cable • Router, Hub, Switch, Bridge, Gateway • Low-Level Protocols/ Concepts • TCP/IP (Transmission Control Protocol/Internet Protocol) • Packet Switching

13. What is the Internet? • The largest network of networks in the world. • Uses TCP/IP protocols and packet switching . • Runs on any communication substrate. • http://som.csudh.edu/cis/lpress/history/arpamaps/

14. Brief History of the Internet • 1968 - DARPA (Defense Advanced Research Projects Agency) contracts with BBN (Bolt, Beranek & Newman) to create ARPAnet (Advanced Research Projects Agency) • 1970 - First five nodes: • UCLA • Stanford • UC Santa Barbara • U of Utah, and • BBN

15. Brief History of the Internet • 1974 - TCP protocol invented by Vint Cerf • 1984 – On January 1, the Internet with its 1000 hosts converts en masse to using TCP/IP for its messaging • 1968 is really the “birth” of the Internet • 1984 is really the “high-school graduation” of the Internet

16. ARPANET is Born 1968 TCP/IP Created 1972 Internet Named TCP/IP Used 1984 Hypertext Invented 1965 WWW Created 1989 Packet Switching Invented 1964 Mosaic Created 1993 First Vast Computer Network Envisioned 1962 Age of eCommerce Begins 1995 1962 1995

17. We will prove that packet switching works over a WAN. Hypertext can be used to allow rapid access to text data Packet switching can be used to senddigitized data though computer networks Great things can be done witha vast world-wide network We can do it cheaply by using Digital circuits etched in silicon. We do it reliably with “bits”, sending and receiving data We can access information using electronic computers 1945 1962 1968

18. Great efficiencies can be accomplished if we use The Internet and the World Wide Web to conduct business. The World Wide Web is easier to use if we have a browser that To browser web pages, running in a graphical user interface context. Computers connected via the Internet can be used more easily if hypertext links are enabled using HTML and URLs: it’s called World Wide Web The ARPANET needs to convert to a standard protocol and be renamed to The Internet We need a protocol for Efficient and Reliable transmission of Packets over a WAN: TCP/IP Ideas from 1940s to 1968 1968 1995

19. Claude Shannon • The Father of Modern Information Theory • Created the idea that all information could be represented using 1s and 0s. Called these fundamental units BITS. • Won a Nobel prize for his master’s thesis in 1936 Source: http://www.research.att.com/~njas/doc/ces5.html

20. Vannevar Bush • Summary: Vannevar Bush established the U.S. military/university research partnership that later developed the ARPANET. • He also wrote the first visionary description of the potential use for information technology, inspiring many of the Internet's creators. Source: Livinginternet.com

21. Paul Baran • Paul Baran developed the field of packet switching networks • Worked for RAND organization (first think tank) • Baran's architecture was well designed to survive a nuclear conflict, and helped to convince the US Military that wide area digital computer networks were a promising technology. Source: Livinginternet.com

22. Leonard Kleinrock • One of the pioneers of digital network communications • Helped build the early ARPANET.

23. Vinton Cerf • Summary: Vinton Cerf is co-designer (with Bob Kahn) of the TCP/IP networking protocol. • Worked for DARPA, projects include d • the Packet Radio Net (PRNET), and • the Packet Satellite Network (SATNET). Source: Livinginternet.com

24. Tim Berners-Lee • The inventor of HTML. • Now works for Laboratory for Computer Science (LCS)at the Massachusetts Institute of Technology (MIT). • Directs the W3 Consortium, an open forum of companies and organizations with the mission to realize the full potential of the Web. Source: w3c.org

25. Internet Growth Trends • 1977: 111 hosts on Internet • 1981: 213 hosts • 1983: 562 hosts • 1984: 1,000 hosts • 1986: 5,000 hosts • 1987: 10,000 hosts • 1989: 100,000 hosts • 1992: 1,000,000 hosts • 2001: 150 – 175 million hosts • 2002: over 200 million hosts • By 2010, about 80% of the planet will be on the Internet

26. Important Milestones September 2002 > 200,000,000 IP Hosts > 840,000,000 Users Netsizer.com – from Telcordia

27. Sept. 1, 2002 Dot-Com Bust Begins Chart by William F. Slater, III The Internet was not known as "The Internet" until January 1984, at which time there were 1000 hosts that were all converted over to using TCP/IP.

28. Internet’s Growth • To get a market of 50 Million People Participating: • Radio took 38 years • TV took 13 years • Once it was open to the General Public, The Internet made it to the 50 million person audience mark in just 4 years!

29. URLs • Universal Resource Locator • www.cs.siena.edu • Human-readable WWW Address

30. IP Address • Numeric Internet Address • Part of the TCP/IP Protocol • URLs are translated into IP Addresses by DNS Servers • DNS Domain Name System