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Internet and the World Wide Web CIS 141 Lecture

Internet and the World Wide Web CIS 141 Lecture. Thad Crews Western Kentucky University. Part 1. the Internet. 1980s. Just Kidding!. 1990s. 1970s. the Internet is Just A Passing Fad. 2000s. The Internet is a “global network of networks.”. What is the Internet?.

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Internet and the World Wide Web CIS 141 Lecture

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  1. Internet and the World Wide WebCIS 141 Lecture Thad Crews Western Kentucky University

  2. Part 1 the Internet

  3. 1980s Just Kidding! 1990s 1970s the Internet is Just A Passing Fad 2000s

  4. The Internet is a “global network of networks.” What is the Internet? Visualization of the Internet’s topology Networks connected to networks connected to networks

  5. The Internet (or “Net”) • The Internet (or “net”) is “a global network of networks.” • More specifically, the Internet is the world’s largest computer network, providing a vast array of services to individuals, businesses, and organizations around the world. • The Internet is NOT a gimmick or a fad. Sorry Firby

  6. Internet Backbone • The Internet backbone consists of the main pathways and connections of the Internet owned primarily by telecom companies. Verizon’s/MCI’s UUNet carries ~28% of Internet traffic

  7. Smaller Networks Connect to the Backbone

  8. History of the Internet (in context) • 1943 to 1946  ENIAC built • 1950s  Sputnik program (Russian unmanned space missions) • 1958  the United States formed Advanced Research Projects Agency (ARPA) and National Aeronautics and Space Administration (NASA). • 1969  NASA lands a man on the moon, ARPA started ARPANET (which could evolve into the Internet). Email was the “killer app” of ARPANET. • 1983  ARPANET was migrated to TCP/IP protocol • Early 1990s  World Wide Web developed • 1993  Mosaic web browser (included graphics)

  9. And Now for a Confusing Visual Timeline…

  10. And THAT is why we need Protocols because Protocols Determine Behavior • Protocols are rules that govern behavior. • Human protocol specifies how a person must behave with other people in a particular situation. • Example: Military protocol • Example: Diplomatic protocol • Example: Dating protocol • Internet Protocol specifies how a network must behave with other networks to participate on the Internet.

  11. Internet Protocol • TCP/IP (or simply IP) is the Internet protocol that governs all Internet communications. • BIG IDEA: Every node on the internet has a unique IP address (just like every house has a unique mailing address.) • BIG IDEA: Data sent over the Internet is broken into packets and then routed to the target IP address.

  12. Internet Protocol – Big Idea #1: IP Address Every node on the Internet has a unique IP address(just like every house has a unique mailing address.) • An IP address is 32 bits and is typically written in chunks of 8 bits (for example 161.6.94.119). • To make things easier, an IP address can be mapped to a domain name (for example www.wku.edu). • Domain names are optional and must be registered with the Domain Name System (DNS) if it is to be available on the Internet.

  13. What is a Domain Name • The Domain Name System (DNS) is like an Internet "phone book" that translates human-friendly computer URL hostnames into specific IP addresses. • For example, www.wku.edu maps to the IP address 161.6.94.119 (and can be verified by opening a browser and entering http://161.6.94.119 to get the WKU homepage). • A Domain Name must be registered with the DNS if it is to be available on the Internet. • A Domain Name is used by both web URL and email.

  14. Internet Protocol – Big Idea #2: Packets and Routing Data sent over the Internet is broken into packets and then routed to the target IP address. • Data is broken into fixed-sized packets and addressed to a specific computer (using its unique IP address). The packets are then sent through the network independently. They may each take a different route and they may arrive in different order. When the do arrive, the packets are un-packed in the correct order and the data is displayed on the destination machine.

  15. A Picture is Worth a Thousand Words

  16. More About Domain Names www.amazon.com www.imdb.org www.wku.edu www.whitehouse.gov The last part of the domain name is the “top-level domain” that describes the domain type. There can also be an optional two letter country code: .us (United States) .ca (Canada) .jp (Japan) .cn (China)

  17. Questions About the Internet • http://www.disney.com • http://www.disney.eu • http://www.disney.us

  18. Questions About the Internet • What is the ICAAN organization? • ICANN (Internet Corporation for Assigned Names and Numbers) has the overall responsibility for managing the Domain Name System (DNS), which is the database of all domain names and their associated IP addresses. • Who owns the Internet? • No one owns the Internet. The Internet is made up of the many national and international communication networks to provide connections between individuals, companies, organizations, and governments. Businesses and the global economy depend on the proper functioning of the Internet.

  19. Is Email Private? • The word “mail” suggests a strong analogy between email and physical mail (letters delivered by the US Post Office). Unfortunately, this is a poor analogy. • Physical mail is sealed mail will most likely arrive at its destination unopened, and will most likely never be seen by anyone other than the recipient. • Email is electronic and there are actually multiple copies of your email floating around cyberspace, including copies on your machine, your recipient’s machine, your mail server, your recipient’s mail server, and any number of devices in-between. • Email is NOT private. Think of email as a postcard, rather than a letter, and save controversial comments for face-to-face communication.

  20. Is the Internet and the Web the same thing? • No

  21. Part 2 The world Wide Web

  22. The World Wide Web (or “Web”) • The Web is a collection of web pages containing hypertext (words, graphics, sounds, pictures, videos) with links to other web pages. • The Web is not simply another name for the Internet, but is one of many applications and services available on the Internet (along with email, teleconferencing, VOIP, FTP, etc.) • Before the Web, navigating the Internet for information was a complicated process involving using memorized text commands. (Similar to the OS command prompts).

  23. The Web versus the Net • The Internet has been around since 1969 (or 1983). • The Internet is a framework that supports many services/applications including email, VOIP, telecommunications, and the Web. • The Web has only been available since 1990. • The Web is one of the many services/applications that run on the Net.

  24. History of the World Wide Web (in context) • In 1990 Tim Berners-Lee develops HTML and HTTP, and creates the first few Web pages at CERN. • In 1992, the first personal computers were connected to the Internet. (Previously all Internet computers had been mainframes). • In 1993 the University of Illinois released version 1.0 of Mosaic, a web browser. This was the first browser with strong support for images and graphics. • By 1994 there was rapidly growing awareness in the Internet and the Web (which had previously been used primarily by academics and military only.)

  25. April 12, 1993 July 25, 1994

  26. July 5, 1993 issue of The New Yorker, (Vol.69 (LXIX) no. 20)

  27. Rapid Growth

  28. Another Confusing Visual Timeline…

  29. And THAT is why we need Protocols because Protocols Determine Behavior • The protocol of the Web is called HTTP (Hypertext Transfer Protocol) is the protocol of the Web. HTTP controls communication between Web clients and servers. • HTTP involves a web client using a web browser (such as Internet Explorer, Firefox, Chrome or Safari) to request web pages from web servers. • HTTP involves a web server thatstores and delivers web pages and other web resources (video, pictures, files, etc).

  30. And THAT is why we need Protocols because Protocols Determine Behavior • The protocol of the Web is called HTTPS (Secure Hypertext Transfer Protocol) is the protocol for secure communication between Web clients and servers.

  31. Domain Names are part of a URL http://www.wku.edu/~jim.lindsey/cis141/orientation/Orientation.html https://www.amazon.com/gp/cart/view.html • Protocol • Domain name (maps to an IP address & a web server) • Directory or Path • File (document) name and extension

  32. URL versus Email http://www.organization.org/directory/filename.html http://www.schoolname.edu/directory/filename.html username@www.organization.org username@www.schoolname.edu • Both can use the same registered Domain Name • URLs identify specific files from that Domain Name • Email addresses identify specific users at (@) the Domain Name

  33. Hands On • Find the IP address for www.usatoday.com • Enter the usatoday IP address in a browser and confirm the usatoday appears. • Find the IP address for your computer (reverse DNS lookup). • Enter your IP address in a browser and confirm that the page does NOT appear. (In other words, there is no web site hosted on your PC.) • NOTE: If your PC was running a web server application (such as Microsoft IIS or Apache), then browsing to your IP address could respond with a web page.

  34. Part 3 The CHANGING WEB(and some implications)

  35. Encyclopedia Britannica • Founded in 1768 • 122,264 articles

  36. wikipedia.org • Founded in 2001 • 3,770,000+ articles An online encyclopedia that consists purely of articles contributed by visitors. As of July 23, 2008 it had 3,770,000 English articles contributed by volunteers around the world since January 15, 2001.

  37. Comparison The free online resource Wikipedia is about as accurate on science as the Encyclopedia Britannica, a study shows. – BBC NEWS Thursday, 15 December 2005

  38. Star Wars KidsA Web Illustration of Input-Process-Output Star Wars Kids (Original) • LINK http://www.youtube.com/watch?v=HPPj6viIBmU Star Wars Kid ReMixes • LINK http://www.youtube.com/watch?v=3GJOVPjhXMY • LINK http://www.youtube.com/watch?v=TytJRejBWHU • LINK http://www.youtube.com/watch?v=YvEibGgp-GA • LINK http://www.youtube.com/watch?v=2URImmLYAsQ • LINK http://www.youtube.com/watch?v=Zd5HjY1ZtLQ • LINK http://www.youtube.com/watch?v=aXiw-fe0Vf4

  39. Another Web Input-Process-Output Example Read the full story at: http://latimesblogs.latimes.com/washington/2009/08/obama-joker-artist.html

  40. And Finally, consider this…

  41. End Lecture

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