The Internet is a global system of
interconnected computer networks that use the standard Internet protocol suite
(often called TCP/IP, although not all applications use TCP) to serve billions
of users worldwide. It is a network of networks that consists of
millions of private, public, academic, business, and government networks, of
local to global scope, that are linked by a broad array of electronic, wireless
and optical networking technologies. The Internet carries an extensive range of
information resources and services, such as the inter-linked hypertext
documents of the World Wide Web (WWW) and the infrastructure to support email.
Most traditional communications media including
telephone, music, film, and television are reshaped or redefined by the
Internet, giving birth to new services such as Voice over Internet Protocol
(VoIP) and Internet Protocol Television (IPTV). Newspaper, book and other print
publishing are adapting to Web site technology, or are reshaped into blogging
and web feeds. The Internet has enabled and accelerated new forms of human
interactions through instant messaging, Internet forums, and social networking.
Online shopping has boomed both for major retail outlets and small artisans and
traders. Business-to-business and financial services on the Internet affect supply
chains across entire industries.
The World
Wide Web (abbreviated as WWW or W3, commonly known as the
Web, or the "Information Superhighway"), is a system of
interlinked hypertext documents accessed via the Internet. With a web browser,
one can view web pages that may contain text, images, videos, and other multimedia,
and navigate between them via hyperlinks.
The terms Internet and World Wide Web are often used in everyday speech
without much distinction. However, the Internet and the World Wide Web are not
one and the same. The Internet is a global system of interconnected computer
networks. In contrast, the Web is one of the services that runs on the
Internet. It is a collection of text documents and other resources, linked by
hyperlinks and URLs, usually accessed by web browsers from web servers. In
short, the Web can be thought of as an application "running" on the
Internet.
First, the browser resolves the server-name portion of the URL (example.org)
into an Internet Protocol address using the globally distributed database known
as the Domain Name System (DNS); this lookup returns an IP address such as 208.80.152.2.
The browser then requests the resource by sending an HTTP request across the
Internet to the computer at that particular address. It makes the request to a
particular application port in the underlying Internet Protocol Suite so that
the computer receiving the request can distinguish an HTTP request from other
network protocols it may be servicing such as e-mail delivery; the HTTP
protocol normally uses port 80. The content of the HTTP request can be as
simple as the two lines of text.
