Network, Internet and World Wide Web

1. Network, Internet and World Wide Web Essential Concepts Natalia Mosina - 2005

2. Network • Most people work in a network environment A network is a collection of computers connected together with special hardware and software to manage it. LAN – local area network (small area) WAN – wide area network (long distances)

3. From LAN to WAN (a) Home Network (b) Local Area Network

4. From LAN to WAN (continued) (c) Wide Area Network

5. The Internet • A network of networks, interconnected collection of networks • Began in 1960s as government (military) project • It is a hardware! Consists of computers and the communications links that connect them The World Wide Web • A subset of the Internet consisting of all computers with hypertext or hypermedia documents • These documents contain references (links) to other documents which may be on a different computer anywhere in the world • Began in 1991 at the European Particle Physics Laboratory (CERN) in Switzerland

6. The World Wide Web • Began in 1991 at the European Particle Physics Laboratory (CERN) in Switzerland • It is a software! Consists of different files, documents, and software that stores and retrieves those files. Web is a collection of files that reside on Web Servers that are located all over the world.

7. Client vs. Server • When you connect to Internet to become part of the web, your computer becomes a Web client in a worldwide client/server network. • Web browser is the software that you run on your computer to make it work as a Web client.

8. A Client/Server Model • A server (Web server or Web site) is any computer that stores documents and furnishes them upon request • A client is any computer that requests services (requests and then displays documents ) • Every client must be able to display every document from every server and does so through a browser (e.g., Netscape or Internet Explorer)

9. Acronyms • HTTP – HyperText Transfer Protocol is used to transmit Web documents • HTML – HyperText Markup Language is the language for all Web documents • ISP – Internet service provider • IP - Internet protocol • TCP - Transmission Control protocol • DNS – Domain Name System

10. Connecting to the Internet • At Work or School • Via a Local Area Network • At Home • Traditional Modem (56Kbps) • Cable Modem • Uses TV cable • Requires network card • DSL Modem • Voice and data on the same line • Requires network card

11. Uniform Resource Locator (URL) http://www.prenhall.com/reed/index.html Name of the page Or document Web Server Protocol (means of access) Directory where the Page is stored

12. URL • Top-level domains include “edu,” “gov,” and “org,” but “com” is most common • Examples: • www.microsoft.com • www.nba.com • www.whitehouse.gov • www.miami.edu

13. E-Mail (Electronic Mail) • E-mail is simply a means of sending messages via computer • Business is using more e-mail and fax • To access, you must have a mail server and/or software • Each person has a username and pass-word • All mail programs allow you to Send, Compose, Reply, and Forward

14. An E-mail Address • Every e-mail address is unique and consists of two parts, a user name and a host computer: • johndoe@anyschool.edu • The@ sign is required • The host computer can be omitted if you are logged onto the same network or host computer