The Internet

apprehensiveheehawNetworking and Communications

Oct 25, 2013 (3 years and 5 months ago)

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Connecting one computer to another computer creates
a
network.

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
geographic area.


Wired



Wireless



Combination

The Internet, also
referred to as the
Net, is a
worldwide system
of networked
computers that
uses a common
set of rules that
enable
collaboration,
communication,
and commerce.

Need for a system that could survive major
losses

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
Agency (ARPA),
created a small network called
ARPANET
.


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 destination.


The rules used to manage data
exchange are called
protocols
.
Protocols are standards that allow
networks to communicate even if
they use equipment from different
manufacturers.

The two major protocols for transmitting packets across the
network are referred to together as Transmission Control
Protocol/Internet Protocol(TCP/IP).


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
Internet Protocol.
An IP
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
66.249.71.56
.

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

(URL).

A
domain name
is the part of the
text
-
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
addresses.

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.


Berners
-
Lee used a
browser


a program that requests and
displays Web pages


to display documents. He named his
browser
WorldWideWeb

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
Mosaic
. 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
Hypertext Markup
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
are called
hyperlinks.
The links are typically
identified with a different color font and
underlining.

A company or organization that sells the service of its gateway is
called an
Internet Service Provider (ISP).



Types of ISPs



Dial
-
Up Telephone Service


slow speed technology that uses
telephone lines





DSL Telephone Service


high speed technology that uses
telephone lines



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