Transcript Web
Internet Chapter What is the Internet History of the Internet How data travels on the Internet Anatomy of a URL Purpose of a Web Browser DNS (Domain Naming System) New Applications of the Internet • A collection of computers and devices connected together via communications media such as cables, telephone lines, and modems. • LAN /MAN/WAN • The Internet is the world’s largest collection of computer networks. Network Local Area Network Just remember… It took 38 years for radio to reach 50 million users 13 years for television to reach 50 million users Less than 4 years for the Web to do the same! By 2010, about 80% of the planet will be on the Internet History of the Internet ARPANET Goal: To allow scientists at different locations to share information Networking project by Pentagon’s Advanced Research Projects Agency (ARPA)/ 4 sites involved Became functional September 1969 Goal: To function if part of network were disabled History of the Internet Today More than 350 million host nodes 1984 More than 1,000 host nodes 1969 Four host nodes History of the Internet Who controls the Internet? Now: World Wide Web Consortium (W3C) Oversees research, sets standards and guidelines Tim Berners-Lee, director Future: Internet2 (I2) Internet-related research and development project Develops and tests advanced Internet technologies How the Internet Works Slow-speed technology Dial-up access modem in your computer uses a standard telephone line to connect to the Internet Connection must be established each time you log on. Slow but inexpensive High-speed connection Digital subscriber line (DSL), cable telephone Internet services (CATV), cable modem, fixed wireless, and satellite modems Connection is always on— whenever the computer is running How you Access the Internet Service Providers (SP) enable Internet? 1. 2. 3. ISP, Regional or National SP OSP (AOL and MSN, for example) Wireless Internet Service Provider How Does the Internet Work? Protocols Internet backbone Rules/standards Establish connections between two or more computers The main Internet pathways and connections Internet service providers (ISP) Provide users with access to the Internet Internet Protocols Transmission Control Protocol (TCP) Internet Protocol (IP) Internet IP address A packet switching network Four numbers (0 to 255) separated by periods, such as 64.233.161.104 Domain names Associated English names assigned to IP addresses Domain name Text version of Internet protocol (IP) address What is a domain name? Number that uniquely identifies each computer or device connected to Internet Domain Name System Converts domain names into IP addresses Without the DNS, the Internet would crash One of the largest, distributed databases on the planet Every domain name has a domain name server somewhere that handles its requests Packet Switching Data is sent out in sequence Small chunks (packets) of data Packets are passed from node to node "Packet switching is the breaking down of data into datagrams or packets that are labeled to indicate the origin and the destination of the information and the forwarding of these packets from one computer to another computer until the information arrives at its final destination computer. This was crucial to the realization of a computer network. If packets are lost at any given point, the message can be resent by the originator." The World Wide Web A worldwide collection of electronic documents Also called the Web Each electronic document is called a Web page Can contain text, graphics, sound, video, and built-in connections A Web site is a collection of related Web pages The World Wide Web How do handheld computers and cellular telephones access Use a microbrowser the Web? that displays Web pages that contain mostly text Must be Internetenabled The World Wide Web What is downloading? The process of a computer receiving information Depending upon connection speed, downloading can take from a few seconds to several minutes The World Wide Web Lets you find information by clicking links rather than entering keywords Search tool with organized set of topics and subtopics What is a subject directory? The World Wide Web What is a search engine? Program used to find Web sites and Web pages by entering words or phrases called search text Also called a keyword The World Wide Web Portal News Informational Business/Marketing Educational Entertainment Advocacy Blog Wiki Content Aggregator Personal What are the eleven basic types of Web sites? The World Wide Web A Web site that offers a variety of services from one, convenient location, usually for free What is a portal? Searching, sports, e-mail, news, weather, auctions, Web communities (Web sites that join people with similar interests) The World Wide Web Business that gathers and organizes Web content and then distributes, or feeds, the content to subscribers for free or a fee What is a content aggregator? The World Wide Web What is streaming audio? The process of transferring audio in a continuous and even flow Enables you to listen to music as it downloads to your computer The World Wide Web What are plug-ins? Programs that extend the capability of a browser You can download many plug-ins at no cost from various Web sites Web Publishing Development and maintenance of Web pages What is Web publishing? Step 1. Step 2. Plan the Web site Analyze and design the Web site Step 3. Create the Web site Step 5. Maintain the Web site Step 4. Deploy the Web site E-Commerce Short for electronic commerce Business transaction that occurs over the Internet What is E-commerce? Business to consumer (B2C) Sale of goods to general public Consumer to consumer (C2C) One consumer sells directly to another Business to business (B2B) Business providing goods and services to other businesses Other Internet Services What is FTP? File Transfer Protocol—Internet standard that allows you to upload and download files with other computers on the Internet Other Internet Services What is instant messaging (IM)? A real-time Internet communications service that notifies you when one or more people are online and allows you to exchange messages or files Step 1. Login to the IM server Step 2. The server determines if any of your established friends, family, or coworkers, called buddies, are online Step 5. Your buddy replies Step 3. You send instant messages to an online buddy Step 4. Your Instant Message travels through a messaging server and then to the online buddy Additional LES Rules Never send out E-Mail that you would not want to become public Never send abusive, threatening, harassing or bigoted messages Do not type in UPPERCASE. This is called shouting and perceived to be offensive. Use a normal mix of upper and lowercase letters Think twice before sending E-Mail. You cannot get it back. Personal notes should not sent via e-mail