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 • gopher:for 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..