Internet and the World Wide Web
CIS 141 Lecture
Thad Crews
Western Kentucky University
Part 1
THE INTERNET
1980s
1970s
1990s
THE INTERNET
IS JUST A PASSING FAD
2000s
The Internet is
What is the Internet?
a “global network
of networks.”
Visualization of the Internet’s topology
Networks connected to networks connected to networks
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
Internet Backbone
• The Internet backbone consists of the main
pathways and connections of the Internet owned
primarily by telecom companies.
Network Service
Providers
Verizon’s/MCI’s UUNet carries ~28% of Internet traffic
27.9%
Verizon/MCI/UUNET
10.0%
AT&T
6.5%
Sprint
6.3%
Genuity (level 3)
4.1%
PSINet
3.5%
Cable & Wireless
2.8%
XO Communications
2.6%
Verio
1.5%
Qwest
Smaller Networks Connect to the Backbone
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)
And Now for a Confusing Visual Timeline…
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.
Internet Protocol
• TCP/IP (or simply IP) is the Internet protocol that
governs all Internet communications.
1. BIG IDEA: Every node on the internet has a unique
IP address (just like every house has a unique
mailing address.)
2. BIG IDEA: Data sent over the Internet is broken
into packets and then routed to the target IP
address.
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.
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.
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.
A Picture is Worth a Thousand Words
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)
Questions About the Internet
• http://www.disney.com
• http://www.disney.eu
• http://www.disney.us
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.
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 inbetween.
• Email is NOT private. Think of email as a postcard, rather than a
letter, and save controversial comments for face-to-face
communication.
Is the Internet and the Web the same thing?
• No
Part 2
THE WORLD WIDE WEB
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).
The Web versus the Net
• The Internet has been
around since 1969 (or
1983).
• The Web has only been
available since 1990.
• The Internet is a framework • The Web is one of the many
that supports many
services/applications that
services/applications
run on the Net.
including email, VOIP,
telecommunications, and
the Web.
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.)
April 12, 1993
July 25, 1994
July 5, 1993 issue of The New Yorker, (Vol.69 (LXIX) no. 20)
Rapid Growth
Another Confusing Visual Timeline…
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 that stores and
delivers web pages and other web resources
(video, pictures, files, etc).
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.
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
1.
2.
3.
4.
Protocol
Domain name (maps to an IP address & a web server)
Directory or Path
File (document) name and extension
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
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.
Part 3
THE CHANGING WEB
(AND SOME IMPLICATIONS)
Encyclopedia Britannica
•Founded in 1768
•122,264 articles
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.
Comparison
Topics Covered
4000000
3500000
3000000
2500000
2000000
1500000
1000000
500000
0
Britannica
Wikipedia
The free online resource Wikipedia is about as accurate on
science as the Encyclopedia Britannica, a study shows.
– BBC NEWS Thursday, 15 December 2005
Star Wars Kids
A 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
Another Web Input-Process-Output Example
Read the full story at:
http://latimesblogs.latimes.com/washington/2009/08/obama-joker-artist.html
And Finally, consider this…
END LECTURE