Prepared by Gena Casas

1
The Internet An Introduction

• Prepared by Gena Casas

2
What is the Internet

• A worldwide connection of interconnected computer
  networks.
• A network is a communications system on which
  computers share resources and information.
• More than 20 million computers and more than
  45,000 networks.
• Uses packet switching and the TCP/IP protocol.

3
What is the World Wide Web

• A part of the Internet.
• Collection of hypertext Web documents that can be
  shared over the Internet.
• Web documents contain links that lead to other
  Web pages and Internet resources.
• Web documents contain graphics, sounds,
  animation, video, and other interesting ways to
  present information.

4
Why is the Web Important?

• The Internet is the newest medium for human
  interaction communication.
• The Web is the only part of the Internet which is
  graphical.
• Electronic Commerce is conducted over the Web.
• Electronic Publishing needs the Web.

5
Why is the Web Important?

• The Web is a new educational medium for
  instruction in the office, the home, and at
  school.
• The Web is important for entertainment.
• The Web is a major component of the Information
  Superhighway.
• Corporate Intranets, Extranets depend on the Web.

6
Why is the Web Important?

• The Web, TV, Modem, Telephone, Fax, Radio will
  soon combine . Cable or Wireless.
• The Web provides Worldwide Connectivity.

7
What is a Web Site

• A collection of one or more Web pages (HTML
  documents) viewable on the Internet.
• Web pages are stored on computers called Web
  servers.
• A Web browser such as Netscape Navigator /
  Communicator, or Internet Explorer is used to
  access Web sites.
• The relationship between browsers and Web servers
  is called a client/server relationship.

8
Accessing Web Pages

• Web pages accessed by their unique URL - (Uniform
  Resource Locator.
• URLs - Four-part addressing scheme
• Tells browser which transfer protocol to use
• Contains the domain name of the computer where
  the document resides
• Contains the pathname on the computer
• Contains the filename of the document

9
Format of URLs

• URLs have the following format
• protocol//machine address/path/filename
• Example
• http//www.udel.edu/interlit/chp1.html

10
Protocol

• The first part of the URL.
• How the communication is handled.
• http for Web sites
• ftp for FTP sites
• gopherfor gofer sites
• telnet for telnew sites
• Followed by //

11
Domain Names

• Second part of the URL is the machine address
  which contains the following
• hostname.subdomain.top-level-domain name
• Domain names appear in the right-most position in
  the machine address.
• Each host on the Internet is assigned a domain
  name based on its usage
• .edu educational .gov government
• .com commercial .org other organizations

12
Path Filename

• Path - third part of the URL
• Points to a specific site within the server.
• Starts and ends with forward slashes.
• Filename - fourth part of the URL
• The name of the document
• Web page filenames end with .htm or .html

13
The W3 Consortium

• Joint WWW project to help provide information and
  archives relating to WWW development.
• Two sites - One in the United States, one in
  Europe.
• The major players
• Tim Berners-Lee at MIT
• CERN - European Particle Physics Lab
• INRIA - French National Institute for Research in
  Computing and Automation

14
The W3 Consortium

• Goal - To provide the Web with the following
• A repository of information.
• A reference code implementation to promote
  standards.
• Various prototype and sample applications to show
  how new technology can be used.
• Latest standards can be found at
• http//www.w3.org/

15
The beauty is in the detail..