Connecting one computer to another computer creates
A computer network covering a small physical area,
like a home, office, or small group of buildings, such
as a school, or an airport.
A computer network
that connects two or
more LANs and usually
covers a larger
The Internet, also
referred to as the
Net, is a
uses a common
set of rules that
Need for a system that could survive major
In 1962, the United States had several
research facilities around the country that
used computers. The government wanted to
speed up research by connecting the labs so
their computers could exchange data.
In 1968, The
Advanced Research Projects
created a small network called
In 1982, a new method was
created to allow messages to be
sent on multiple pathways.
The data is divided into small
packages that is transmitted
independently and reassembled at
The rules used to manage data
exchange are called
Protocols are standards that allow
networks to communicate even if
they use equipment from different
The two major protocols for transmitting packets across the
network are referred to together as Transmission Control
For example, if you send a file to a friend’s computer TCP/IP
breaks the file into several packets and labels each packet with
the Internet address of your friend’s computer. Since these
packets will travel separate routes, some arriving sooner than
others, TCP/IP assigns a sequence number to each of the
packets. These numbers will be used by the TCP/IP on your
friend’s computer to reassemble the packets. This complicated
process of TCP/IP takes place in a matter of milliseconds.
Regardless of its physical location, each computer
connected to the Internet has a unique address called
its IP address. IP stands for
address is a number that uniquely identifies each
computer connected to the Internet to other
computers connected to the Internet, for the purpose
of communication and transfer of data packets.
IP address are grouped as a series of four sets of
numbers separated by dots, such as
An addressing system was devised that could provide each resource
on the Internet with a unique address. The system is called the
Uniform Resource Locator
is the part of the
based URL that identifies the
company or organization that owns
the Web site.
Because a domain name may be
used only once throughout the
entire world an organization called
Internet Corporation for Assigned
Names and Numbers (ICANN)
oversees the registration of new
domain names and administers IP
In 1989, Tim Berners
Lee, a computer programmer,
developed a way for computers to share text documents.
The documents were placed on computers that acted as
servers, and other computers were able to run programs
called clients that could retrieve and display the documents.
Lee used a
a program that requests and
displays Web pages
to display documents. He named his
and made it available for free to
anyone on the Internet that wanted to use it.
In 1992, Marc Andreessen and several other students at the
University of Illinois took Berners
Lee’s browser and added the
ability to embed graphical elements. They called their browser
. It was available as a free download on the Internet and
by 1993 more than one million people were using it.
Today the three most common Web browsers are Internet
Explorer, Firefox, and Safari.
Web browser programs use
Language, or HTML
to describe how text and figures
should be displayed.
A document that is written in HTML and displayed
by a browser is a Web page.
The method used to transfer Web pages is called
HTTP or Hypertext transfer protocol
Web pages contain links to other web pages, which
The links are typically
identified with a different color font and
A company or organization that sells the service of its gateway is
Internet Service Provider (ISP).
Types of ISPs
Up Telephone Service
slow speed technology that uses
DSL Telephone Service
high speed technology that uses
Cable television Service
high speed technology that uses
coaxial cable and sometimes fiber optic cables
Laptop Connect Card
a device that uses a cellular network
to connect to the Internet.
Internet Usage Statistics
Internet Growth Statistics
Older video explaining the Web
World Wide Web in Plain English