the internet and the world wide web 1. objectives define the internet, and explain how it works....

The Internet and the World Wide Web

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Objectives Objectives • Define the Internet, and explain how it works.• Describe methods for accessing the Internet.• Describe several methods of finding information on the Web • List the most popular Internet services.• Describe the three types of e-commerce.• List the rules of netiquette.• List safe surfing procedures, and identify hazards of the Web.

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What Is the Internet What Is the Internet

Interneto Global system of computers of thousands of privately

and publicly owned computers and networkso Also known as the Neto Started in the 1960so U.S. Department of Defense project

• ARPANET (Advanced Research Projects Agency Network)

• Purpose was to o Create a form of secure communication for military

and scientific purposeso Create a method for transferring such

communication between computers3

What Is the InternetWhat Is the Internet

• Internet—composed of more than 750 million hosts

• Host—computer that has two-way access to other computers:o Receives requests o Replies to those requests

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• Volunteers maintain the Internet networks.

• Private and public groups provide the equipment.

• Network service providers (NSPs)o Maintain the Internet backbone—the main

high-speed routes

Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 5

How Does It Work?How Does It Work?


• Network access points (NAPs)o NAPs allow data to start on one network

then cross over to another network

• Routerso Specialized devices that connect networks,

locate the best path of transmission, and ensure that data reaches its destination


• Interoperabilityo Ability to work with different brands and

models of computers

Transmission Control Protocol/Internet Protocol (TCP/IP)o Provides methods for packaging and

transmitting information



(TCP/IP)(TCP/IP)

Transmission Control Protocolo Manages assembling of a message or file into

smaller packets • Packets are transmitted over Internet• TCP layer on the destination computer

reassembles the packets into the original message

Internet Protocolo Handles the address part of each packet so that

it gets to the right destination


Accessing the Internet: Accessing the Internet: Going OnlineGoing Online

• Internet service providers (ISPs)o Supply and sustain user connections to the Interneto Maintain the hardware and softwareo Protect their sites and networks from outside threats

• Online service provider (OSP)o A for-profit firm that provides a proprietary networko Offers special services only available to subscriberso Examples: MSN and AOL


Accessing the Internet: Accessing the Internet: Going OnlineGoing Online

• Wireless Internet service providero Company that provides wireless Internet accesso Examples: AT&T, T-Mobile, and Verizon Wireless

• Hot spoto Public location that provides Internet access for

wireless deviceso Examples: airport, college campus, or coffee

shop


Methods to access the Methods to access the InternetInternet

o Dial-up access—uses modem and telephone line

o Digital subscriber line (DSL)—high-speed online connection—external modem with telephone lines

o Cable access—high-speed Internet connection—cable modem not a phone line

o Satellite—high-speed Internet service with antenna and dish connected to indoor receive unit (IRU) and indoor transmit unit (IRU)

o Fiber-optic service—high-speed Internet—fiber-optic lines direct


The Internet and the The Internet and the Web: What’s the Web: What’s the

Difference?Difference?• World Wide Web (also known as the Web or WWW)o Contains billions of documentso Part of the Interneto Uses the Internet to transport informationo Separate entity from the Interneto No one owns the Webo Standards and guidelines for the Web are

published by the World Wide Web Consortium (W3C)



Difference?Difference?• Web page

o Document that may include text, graphics, sound, animation, and video

• Web browsero Program that displays Web pages and linked items

• Web siteo Collection of Web pages

• Typically contains a home page (also called an index page)—default page displayed when you enter a site



Difference?Difference?• Hypertext

o Uses links to connect to additional related information

• Hyperlinks or linkso Words and images that bring other documents into

view when clicked

• Hypertext Markup Language (HTML)o Uses tags to specify how a Web page should display



Difference?Difference?• Distributed hypermedia system

o Network-based content development systemo Uses multimedia resources as a means to of navigation or

illustration

• Web 2.0o Current generation of the Webo Provides opportunities to collaborate, interface, and

create new content using blogs, Wikis, and podcasts

• Some issues with Web distribution include:o Dead links (also known as broken links)o Information posted on the Web is not validated.o Information overload due to too much data



Difference?Difference?• The most popular Web

browsers



Difference?Difference?• Plug-ins

o Additional software programs to extend the ability of the browser

o Examples:• Acrobat Reader• Adobe Flash Player• Adobe Shockwave Player• Apple QuickTime• Real Player• Windows Media Player

• Browser cacheo Stores Web page files and graphics on a computer hard

drive when the user visits a site for the first time



Difference?Difference?• Web servers

o Web sites and their associated information are stored here

o Used to recognize information requests, process the requests, and send the requested documents


Finding Information on the Finding Information on the WebWeb

• Internet Protocol (IP) addresso Every device connected to the Internet, including

PCs and servers, is given a unique network identifiero Numerical identification and logical address

• Uniform Resource Locator (URL)o Identifies Internet resource’s type and location

• Complete URL is made up of the Hypertext Transfer Protocol (HTTP), domain name, path, and resource name.

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• Surfing the Webo Type a URL into the address baro Click a tab in the browser windowo Click a hyperlink

• History listo Compiles a list of the Web pages visited

• Favorites or Bookmarks featureo Allows Web pages visited often to be marked


Finding Information on the WebFinding Information on the Web

• Downloadingo Process of transferring a file or document from one computer to

user’s computer

• Uploadingo Process of transferring a file or document from user’s computer to

another computer

• Really Simple Syndication (RSS)o Connection to a Web site that allows users to receive constant

updates

• Aggregatoro Regularly checks each site on your subscriptions list and sends

alerts if new information has been published

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• Wiki (short for the Hawaiian word for “fast”)o Simple Web page where any visitor can post text or images, change

posted information, and track earlier changes

• Blog (short for Weblog)o Internet equivalent of a journal or diary where bloggers post

opinions, thoughts, and interesting links

• Podcastso Audio, image, or video files released by Web syndication

• Podcatcherso Automatically identify and retrieve new files in a given series and

make them availableo Examples: iTunes or Winamp


• Subject guideo Web pages grouped under specific headings—offered by some search

sites

• Portalo Web page that acts as a gateway to diverse sources and presents them

in an organized way

• Clickstreamo Trail of Web links followed to arrive at a particular site

• Search engineso Index databases of Web pages to enable fast information searches

• Spiderso Programs that roam the Web to add new Web pages to search engine

indexes

• Link roto Results from hyperlinks that no longer work or Web pages that have

been removed or restructured

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• Specialized search engineso Index information, such as job advertisements, and

names and addresses



Using Information Using Information from the Webfrom the Web

• Evaluate information obtained from the Web:o Who is author?o Does the author reference sources?o Who is the Web page affiliated with? Who pays for

it?o Is the language objective/dispassionate or

strident/argumentative?o What is the purpose of the page?o Does the information appear to be accurate?o Is the page current?


Using Information Using Information from the Webfrom the Web

• Use Web information for schoolwork. o Access authoritative online sources.o Locate published works.o Provide appropriate online and offline reference

citations in your work.


Exploring Internet ServicesExploring Internet Services


Internet serviceo Set of standards or protocols that identify how computers communicate

through the InternetMessage board

o Similar to a newsgroupo Easier to useo Does not require a newsreader

• Electronic mail (e-mail)o Type of application software that makes sending and receiving

messages through computer networks possible

• E-mail attachmento Computer file included with an e-mail message

• E-mail addresso Unique cyberspace address for each individualo Consists of a user name, the name of the hosting e-mail service, and

the top-level domain

• Spamo Unsolicited e-mails, usually from advertiserso Do not open spam



• Malwareo Malicious software that places a computer

in the spammer’s control

• Spywareo Gathers data from a system without

knowledge

• Botneto Set of infected computers that places

computers under the control of a bot herder



• Instant messaging (IM) systemso Allow immediate, real-time communication with

contacts• Requires additional software• Notifies users when a contact is connected to

the Internet• Spimming—spam for instant messaging



• Internet relay chat (IRC)o Special type of Internet service that gives users

the ability to join chat groups called channels

• Social networkingo Helps people connecto Sites such as MySpace provide the ability to

create large communities online.



Useneto Worldwide discussion system available through

the Interneto Made up of many newsgroups—discussion

groups dedicated to one topico Discussions within newsgroups are in threads—

groupings of commentaries on a particular subject• Standard newsgroups—of high-quality

discussions• Alt newsgroups—created by anyone • Biz newsgroups—devoted to commercial use



• Electronic mailing listso Similar to newsgroups and forums, except

that:• Only subscribers can receive and view

messages.• Messages posted to the mailing list are

automatically sent to everyone on the list.

o Majordomo is a common freeware electronic mailing list manager.



• VoIP (Voice over Internet Protocol)o Users can speak to others over a broadband

Internet connection instead of an analog phone line

o Requires a broadband Internet connectiono A VoIP service provider such as Skypeo A VoIP adapter or computer with supporting

softwareo Calls are usually free to others using the same

service.Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 35


File Transfer Protocol (FTP)o Method to transfer files over the Interneto Use when files are too large to attach to e-mailso Usually requires a user name and a passwordo Use to upload Web pages

Anonymous FTPo Files are available publicly available for

downloadingo Lack of securityo Do not send sensitive material



E-CommerceE-Commerce• E-commerce

o Conducting business through the use of networks or the Internet

• E-tailers (Web-based retailers)o Online merchants

• Online shoppingo Shop for good dealso Use shopping portals to compare prices and

products• Example: PriceGrabber.com

o Look for coupons and rebates


E-CommerceE-CommerceBusiness-to-business (B2B) e-commerce

o Refers to a business providing supplies to other businesses via the Internet

Consumer-to-consumer (C2C) e-commerceo Refers to the exchange of business between

individualso Example: eBay

Business-to-consumer (B2C) e-commerceo Refers to shopping online rather than at a physical

store


E-CommerceE-Commerce• The dot.com phenomenon

o E-commerce primarily uses Web sites with a .com suffix.o Period between 1995 and 2000 called the dot-com boom.o Many dot-coms crashed in 2000.o Amazon.com is a profitable company.

• Drawbacks to B2C e-commerceo Buyers miss speaking with real sales clerks.o Buyers cannot touch merchandise before purchase.o Buyers have to wait for delivery of merchandise.

• Online e-commerce solutions to drawbackso Online chats with live customer service representativeso Provide a wide variety of shipping optionso Provide good customer service by responding quickly to

customer inquiries


E-CommerceE-Commerce• Other growth areas

o Travel reservationso Bankingo Online stock tradingo Nonretail services, such as health, news, and

dating services


Rules of NetiquetteRules of Netiquette• Netiquette

o Series of guidelines for good manners when using an Internet service

• Flameso Angry messages sent by other users


Safe SurfingSafe Surfing• Guidelines for safe surfing

o Never give out identifying information.o Never respond to suggestive messages.o Never open e-mail from an unknown source.o Never allow a child to make arrangements

for a face-to-face meeting alone.o Remember individuals online may not be

who they claim to be.o Set reasonable rules and guidelines for

computer use by children.o Make using the computer a family activity.


Safe SurfingSafe Surfing• Additional online hazards to

avoid:o Malwareo Identity thefto Threats to you and your familyo Unscrupulous vendors


Safe SurfingSafe Surfing• Protecting your identity

o Avoid shoulder-surfers, people who stand close enough to see PIN numbers

o Look for secure Web site features before entering information.• https:// in the address instead of http://• Site seal provided by a security vendor such as

VeriSign• Locked padlock symbol on the Web site—be sure it is

not a fake image• Logo from other site-security entities, such as Verified

by Visa• Message box that identifies you are entering or

leaving a secure siteCopyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall 44

the internet and the world wide web 1. objectives define the internet, and explain how it works....

Documents

networks o

software o

internet networks

proprietary network

subscribers o examples

internet internetcomposed

requests o replies

scientific purposes