How the Internet Works

What is the Internet? Thousands of networks connected Purpose of exchanging information World wide No one owns the Internet It started because of Sputnik

Internet is hardware Physical connections Towers, wires, hubs, servers, etc. Now maintained by major Internet Service Providers MCI Worldcom, Sprint, GTE, ANS, and UUNET

Types of connections Analog (dial up) DSL (always on) Cable Wireless (radio frequency) T1, T2 lines (leased) Satellite

How did the Internet get started? 1950’s US and Russia in Cold War US tried to get advantage Advanced Research Projects Agency (ARPA) in 1958 Connected four computers Grew from that point on re=related

World Wide Web is software (programs) Collection of electronic documents Linked together like spider web Stored in many locations Uses servers all over the globe Accessing documents through Internet connections What is the Web?

What makes up the Web? Personal computer or handheld device Web browser software Internet service provider (ISP) Servers Routers and switches

How the Web works Web pages Stored on web servers Copied and sent to your device URL (Uniform Resource Locator) Web browser

Web Browsers Software program used to access World Wide Web Retrieves data from remote web server Displays web page Popular browsers – Microsoft-Internet Explorer Mozilla-Firefox Google-Chrome Apple-Safari Opera (from Norway) Most browsers work the same way

Using Web URLs Uniform Resource Locator Unique address Identifies web page location on server URL MUST be typed exactly Some large websites have multiple URLs Address bar on your browser

Anatomy of a URL o -- Hypertext Transfer Protocol o Set of rules for transferring files o Needs host (server) and client (your device) o www. -- indicates the page is available on the World Wide Web o learnthenet.com/ -- Domain name o Main part of the URL o Indicates the web server name o english/ -- directory or folder on the web server o start.htm -- a web page inside the english folder

Web pages o Single electronic document o Written in computer language o HTML (Hypertext Markup Language) o URL (Uniform Resource Locator) o Hyperlinks to other web pages

Websites o One or more web pages o Linked together o Relate to a common theme o Home page o First page of the site o “Front door” o Hyperlinks o Used to access other web pages o Internal or external

Navigating the Web o Three main ways to move between web pages or websites o Type URL in address bar o Click a text hyperlink o Clicking a hyperlinked graphic image o Button o Photograph o Drawing

Identifying hyperlinks o Text or graphic that references URL’s of other web pages o Hypertext link o Underlined o Different color (usually blue) o Turns purple after being used o Graphic o Move pointer over the image o If pointer turns into a hand o If URL appears in the status bar at the lower left of your web browser.

How hyperlinks work o Text or graphic hyperlink hides a URL o Clicking hyperlink passes URL to browser o Follows image map o Takes you to different web page o Or different place on the same page

o Similar to a real-life bookmark o Acts as marker for a Web site o “Holds your place” o Faster way to get to page o Add the bookmark to your favorites o Navigate to web page o Choose "Add to Favorites” o Favorites list or Favorites Bar Bookmark

Printing a Web Page o Print button on toolbar will print entire web page o Could be several (or several hundred) pages long o Always use File menu and Print command o Can select what you want to print o Can also Print Preview to see how much will print

Other printing options o Highlight the content you want to print o File menu and Print command o Click on Selection o Prints just what you have selected instead of the whole page o Or copy selected text o Paste in a Word document o Print this document