The internet

FOR 201 MICROCOMPUTER

APPLICATIONS

Background

• Created in 1969, connected computers at UCLA, Stanford Research Institute, U. of Utah, and UC at Santa Barbara

• With an estimated 200 million nodes and 1 billion users, the Internet is connects people of all ages and interests 2

Internet Infrastructure

• The Internet is not owned or operated by any single corporation or government

• The Internet backbone is a network of high-capacity communications links that provides the main routes for data traffic across the Internet

• Backbone links and routers are maintained by network service providers (NSPs)

• An Internet service provider (ISP) is a company that offers Internet access to individuals, businesses, and smaller ISPs

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Internet Infrastructure

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Network Access Points

Internet Infrastructure

• To communicate with an ISP, your computer uses some type of communications device, such as a modem

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Internet Protocols, Addresses & Domains

• A domain name is a key component of Web addresses, e-mail addresses, and addresses on the Web called URLs

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Internet Protocols, Addresses & Domains

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Connection Speed

• Data travels over the Internet at an incredible speed

• The elapsed time for data to make a round trip from point A to point B and back to point A is referred to as latency

• Upstream vs. downstream speed

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Dial-up Connections

• A dial-up connection is a fixed Internet connection that uses a voiceband modem and telephone lines to transport data between your computer and your ISP

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Dial-up Connections

• A voiceband modem converts the signals from your computer into signals that can travel over telephone lines

• Modem speed is measured in bits per second

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DSL, ISDN, and Dedicated Lines• DSL is a high-speed, digital, always-on Internet access

technology that runs over standard phone lines– Most DSL installations require

service technicians• DSL modem

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Cable Internet Service

• Cable Internet service distributes always-on broadband Internet access over the same infrastructure that offers cable television service

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Satellite Internet Service

• Satellite Internet service distributes always-on, high-speed asymmetric Internet access by broadcasting signals to and from a personal satellite dish

• A satellite modem is a device that modulates data signals from a computer into a frequency band that can be carried to the satellite dish where it is converted to another frequency, amplified, and transmitted

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Satellite Internet Service

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Internet To Go• Portable Internet access can be defined as the ability to easily

move your Internet service from one location to another• Mobile Internet access offers a continuous Internet connection

as you are walking or riding in a bus, car, train, or plane

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Wi-Fi Hotspots• A Wi-Fi hotspot is an area in

which the public can access a Wi-Fi network that offers Internet service

• Wi-Fi does not typically provide acceptable mobile Internet access because you can only remain connected within range of the network’s hotspot

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Cellular Data Services• Using cellular phone technology to access the

Internet offers mobility that is not yet possible with most of today’s wired or wireless computer network technologies

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Web Basics• The Web is an interlinked collection of document,

image, video, and sound files• A Web site contains a collection of related

information

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Web Basics• A Web page is the product of one or more Web-based files

displayed in a format similar to a page in a book

• A Web browser is software that displays Web page elements and handles links between pages

• Every Web page has a unique address called URL

• URL stands for Uniform Resource Locator

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HTML

• Hypertext Markup Language

• Set of specifications for creating documents

that a browser can display as a Web page

• Provides a means to describe the structure of

text-based information in a document

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HTML

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Web Browsers• Help you access/see Web pages (display the information)• Popular browsers:– Internet Explorer– Mozilla Firefox– Google Chrome– Apple Safari– Netscape Navigator– Opera

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Search Engine• A Web search engine is a program designed to help

people locate information on the Web by formulating simple keyword queries

• Popular search engines:– Google– Bing– Yahoo– Ask

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