Technology Infrastructure:
The Internet and the World Wide Web
Week of June 10 – June 16

The History of the Internet:
o
A computer network is a group of computers connected to one another in order to
exchange information. The Internet is a large system of interconnected
computers that open the world (p. 53).
o
The Internet’s existence dates back to the 1960s. The U.S. Department of
Defense funded the creation of a worldwide network of computers that could
survive even if a portion of the network were to be destroyed. Their efforts led to
ARPANET in 1969 (p. 54).
o
In 1972, e-mail was invented (p. 54).
o
In the 1970s and 1980s, the focus of the Internet moved from military
applications to academic research functions (p. 53).
o
In 1989, MCI Mail and CompuServe were allowed to offer e-mail services to
individual citizens, greatly expanding the scope of the Internet (p. 55).
o
Also in 1989, Tim Berners-Lee developed a hypertext server program. Hypertext
is a concept in which documents could be stored in a non-sequential, non-linear
fashion and one document can be accessed from another through the use of links
(p. 57).

Could you imagine the Internet without hypertext? Without it, you
would have to read through all of the pages of the Internet in order, one
after another, in much the same way you would read a book. With it,
you can jump from one page precisely to the next page you would like to
see by simply clicking a link.

Berners-Lee also developed HyperText Markup Language (HTML).
HTML is the language in which all Web pages are coded today (p. 58).
o
Despite the emergence of HTML, very few people could read it. In 1993, a
group of students at the University of Illinois wrote a program for rendering
HTML on the screen in a graphical format (p. 59).

This program eventually became the Netscape Navigator Web browser.
Shortly thereafter, Microsoft introduced the Internet Explorer Web
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browser, which is currently the most popular browser in the world (pp.
58-59).

Most people date the birth of the World Wide Web to 1993 and the
creation of the Web browser. Note the World Wide Web and the Internet
are not the same thing. The Internet is the large computer network and
the underlying technologies. The World Wide Web is the graphical
Internet as it is viewed through a Web browser.

A Little More About HTML:
o
Here is a brief analogy explaining the basic fundamentals of HTML. Let’s say
you write a resume and give it a friend and ask them to be proofread it. They
take out their red pen and make suggestions by writing on it. In other words,
they “marked up” your page. Remember that HTML stands for Hyper Text
MARKUP Language. Instead of using a red pen, HTML uses “tags” to markup a
Web page.
o
An HTML document is broken into two elements: document content and
tags. Document content is those parts of the document that the user
actually sees. The tags are used to format the document content, such as
making the document content bold.
o
Below is a brief example of HTML code as well as how a Web browser will
render it to the screen. <B> is an example of an opening tag and </B> is an
example of a closing tag. Everything between the tags will be bolded when
displayed on the screen.
<B>Scott Tollison</B>
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o
Below is another brief example of HTML code as well as how a Web browser
will render it to the screen. <FONT> is an example of an opening tag and
</FONT> is an example of a closing tag. Everything between the tags will be
displayed in blue and made three sizes bigger than normal when displayed on the
screen.
<FONT COLOR=BLUE SIZE=+3>Scott Tollison</FONT>
o
If you would like to view the HTML of any Web page, simply right-click
anywhere in the page (so long as it is not on top of a picture) and select View
Source from the menu that appears.

Technology of the Internet:
o
Circuit Switching vs. Packet Switching:

Our telephone system works by establishing a dedicated connection from
caller to receiver known as a circuit. The circuit is maintained for the
entire length of the call. This method is known as circuit switching (p.
60).

Circuit switching would not work well for the Internet. If someone was
sending a data file to someone else and the circuit was interrupted, the
entire file would be lost. With millions and millions of pieces of data
sent everyday, this would quickly turn into a disaster. This is not a big
deal with telephone traffic because if the circuit was disconnected, the
sender would probably call the receiver back and they would continue
the call from where they left off.

The Internet, instead uses packet-switching technology. In packet
switching, data files are broken down into smaller chunks known as
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packets. Each packet is labeled and numbered. Packets are sent over the
Internet separately and are free to take whatever route is quickest and
easiest to reach their destination. Because packets take different routes
to the same destination, packets may arrive at the destination out of
order. This is no problem, however, because they are numbered, they
may quickly be reassembled (p. 60).

o
LINK FOR PS HERE
Routers:

As packets move from one network to another, computers known as
routers determine the best path for getting the packet from one network
to the next. Routers do through small software programs and the
maintenance of tables of information (p. 60).

These routing tables often include information such as the
location of the nearest routers and how long it will take a data
packet to reach each one.
o
Protocols:

A protocol is a collection of rules for formatting, ordering, and errorchecking data sent across a network. These rules also dictate what is
allowed in a transmission and how it is formatted. Before two computers
exchange data, they must use the same protocol so they can understand
one another (p. 62).

The primary protocol used on the Internet today is TCP/IP (p. 62).

The TCP portion controls the breaking down of data into packets
from the sender and their reassembly at the receiver.

The IP portion controls the routing and addressing functions. In
other words, IP is responsible for finding the right computer.

All computers using the TCP/IP protocol are assigned an IP
address. The number will look something like 216.115.108.245.
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o
Each number is known as an octet and each octet can be
any number between 0 and 255. These octets can form
over 4 billion separate addresses.
o
If you would like to view the IP address of the computer
you are working at, click Start, then Run, then either
command or cmd (depending on what operating system
you are using), and then either ipconfig or winipcfg
(depending on what operating system you are using.

Another necessary protocol is HTTP. HTTP are the rules
responsible for delivering Web pages for the recipients in a
format understood by his of her Web browser. Notice that the
first word of any Web address (a.k.a. URL) is http://.
o
Domain Names:

It would be somewhat difficult to remember the IP addresses of all the
Web sites you like. Therefore, an alternative addressing scheme was
created. Domain names are sets of words that are assigned to specific IP
addresses (p. 64).

Without domain names, you would have to remember the IP address of
every Web site you wished to visit. Would you prefer to remember the
IP address of your favorite Web site (such as 129.33.95.163) or the
domain name of your favorite Web site (such as www.coke.com)?

If you would like a demonstration of how domain names work, try the
following:

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
Open Internet Explorer, and type http://129.33.95.163

Open Internet Explorer, and type http://www.coke.com

Notice they do the same thing.
Most domain names consist three parts (p. 65):

www – which indicates it is part of the world wide web

name of the organization – such as Harvard, coke, pespi, muw
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
and a top-level domain which identifies the type of Web site
(.edu for colleges, .com for commercial, .org for non-profit
organizations, etc.)
o
Since 1998, an organization known as the Internet Corporation for Assigned
Names and Numbers (ICANN) has been responsible for managing domain names
(p. 65).

Intranets vs. Extranets:
o
An intranet does not extend beyond the organization itself. An intranet may use
the same technologies such as a Web browser, e-mail, etc., but it can only be
seen by people working for the company (p. 82).
o
An extranet is similar to an intranet except that an extranet grants access to a
limited portion of the organization’s data to business partners (p. 83).

Internet Connectivity:
o
Connectivity to the Internet is generally through an Internet Service Provider
(ISP). These companies sell Internet access directly to individuals (p. 56).
o
The quality of the connection is generally measured through bandwidth or the
amount of data that can travel through a communication line. The better the
bandwidth, the faster the download files or view Web pages (p. 85).
o
A fundamental unit of computer storage space is the bit. 8 bits equal one byte
which is capable of storing one character. Bandwidth is measured in either Kbps
(kilobits of bits transmitted per second, or thousands of bits per second) or Mbps
(megabits per second, or millions of bits per second).
o
Bandwidth Comparisons (pp. 86-88):

Dial-up (plain-old telephone system, POTS) – 28-56 Kbps of bandwidth

DSL (digital subscriber line) – the textbook reports from 1.5 – 9 Mbps,
but more realistically it is between 1.5-3 Mbps

T1 – 1.544 Mbps (not generally available to individual consumers, but
instead to organizations such as large businesses or colleges)
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
T3 – 44.736 Mbps (not generally available to individual consumers, but
instead to organizations such as large businesses or colleges)

Fiber-optic – up to 10 Gbps (Gbps=gigabits, or billions of bits per
second; not generally used by individual consumers or organizations, but
instead used by telecommunications companies to connect cities over
great distances (p. 88).

If you are interested in testing your own bandwidth, you can do so at
http://reviews.cnet.com/7004-7254_7-0.html.
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