Web Mastering Module Internet Fundamentals

What is the Internet? –Global network of networks –Communicating using same set of rules (protocols/languages) How was the Internet Created? –grew out of a network in the 1960's created by the U.S. Dept. of Defense (ARPANET) –In 1985, Nat’l Science Foundation created NSFNET for education and research

Internet Fundamentals How does it work? –Data is sent in packets –Routers direct packets to their destination using TCP/IP protocol How does TCP/IP work? –Transmission Control Protocol controls how data is broken into packets –Internet Protocol defines how data is routed over the Internet

Internet Fundamentals How do routers know where to send the Internet packets? –Every device on the Internet has a unique address (IP address) –Each IP address has four numbers separated by dots Example: –The Domain Name System associates names with the IP addresses:

Internet Fundamentals How does the Domain Name System work? –All computers are grouped into hierarchical domains –Top level domains are:.com,.org,.edu,.gov,.net,.mil –Name servers know your domain name Example: google.com

Internet Fundamentals How does the Domain Name System work? –A master database keeps track of which domain name servers (DNS servers) are authority for each and every domain –DNS servers store names of domains they have looked up recently

Internet Fundamentals Who runs the Internet? –No one organization –Certain groups establish standards –Internet Society (ISOC) is responsible for standards for Internet infrastructure –Internet Architecture Board (IAB) makes technical recommendations to ISOC

Internet Fundamentals Who runs the Internet? –Internet Corporation for Assigned Names and Numbers (ICANN) coordinates assignment of Internet addresses and domain names

Internet Fundamentals What is the World Wide Web? –A collection of electronic documents stored on servers around the world that are running on the Internet Who develops standards for the WWW? –World Wide Web Consortium (W3C)

Internet Fundamentals How does a Web Browser work? –It downloads and displays pages from a Web Server How does a browser know how to display the pages? –It interprets specially coded text called HTML (Hypertext Markup Language)

Internet Fundamentals What makes a computer a Web Server? –Special software designed to “serve up” web pages and related files How do Web Servers communicate with Browsers? –Using HTTP (Hypertext Transport Protocol)

Internet Fundamentals Anatomy of a URL (Uniform Resource Locater): protocol servername directory filename domain name

Internet Fundamentals Steps to Retrieve a Web Page: 1.User enters URL 2.Web browser communicates with DNS to get IP address 3.Web browser sends request to server using http protocol

Internet Fundamentals Steps to Retrieve a Web Page: 4.Web server receives request and retrieves file and graphics 5.Web server sends file and graphics to Web Browser of requesting (client) computer 6.Web browser interprets the HTML code and displays the page and graphics

Internet Fundamentals Types of Files Served by Web Servers: –Graphics (.jpg,.gif,.png) –Audio (.mp3,.wav,.ra) –Multimedia (.mpeg,.mov,.qt,.avi) –Flash and Shockwave (.swf require plug-ins)

Internet Fundamentals Role of a Webmaster: –Manage a web site –Use the Web to: Communicate a message Evoke an emotion Interact with people

Internet Fundamentals Impact of Internet on Society: –Reduces personal interaction with online shopping and banking, etc. –Enables working from home (telecommuting) –Brings people closer together through , instant messages, auctions, etc. –Makes communicating from a distance easier

Internet Fundamentals Purpose of Acceptable Use Policy: –Defines the rules for use of the Internet –Identifies consequences for misuse of the Internet Types of AUPs –District AUP –Web Mastering Class AUP