How the Internet Works

Chapter 2The Internet and World Wide Web

The Internet

• What are some services found on the Internet?

Fig. 2-1

The Internet - Origins

• 4 hosts ……. Millions of hosts

p. 50

Goal:To function if

part of network were disabled

Became functional

September 1969

ARPANET

Networking project by Pentagon’s Advanced

Research Projects Agency (ARPA)Goal:

To allow scientists at different

locations to share information

The Internet

• Who controls the Internet?

–No one — it is a public, cooperative, andindependent network

–Several organizations set standards

p. 51

World Wide Web Consortium (W3C)

Oversees research, sets standards and guidelines

High-speed connection

High-speed connection

Slow-speed technology

Slow-speed technology

How the Internet Works• How can you connect to the Internet?

p. 51

Dial-up accessmodem in your computer uses a

standard telephone line to connect to the Internet

Dial-up accessmodem in your computer uses a

standard telephone line to connect to the Internet

Digital subscriber line (DSL), cable telephone Internet

services (CATV), cable modem,fixed wireless, and satellite modems

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

Connection is always on—whenever the computer

is running

Connection must be established each time you log on. Slow but inexpensive

Connection must be established each time you log on. Slow but inexpensive

How the Internet Works

• What are ways to access the Internet?

– ISP, regional or national

–OSP (AOL and MSN, for example)

–Wireless Internet Service Provider

p. 52 Next

How Data Travels over the Internet

IP Addresses and Domain Names

• Domain name = “text version” of Internet protocol (IP) address

• IP Address uniquely identifies

each computer or device connected to Internet

Figs. 2-3

Top-Level Domain Names

Figs. 2-4

The World Wide Web

p. 54

A worldwide collection of electronic documents

Each electronic document is called a Web page

Also called the Web

Can contain text, graphics, sound, video, and built-in connections

A Web site is a collection of related Web pages

The World Wide Web – Web Browsers

• Firefox

• Internet Explorer

• (Netscape)

The World Wide Web

• Home page?

– The first page that a Web site displays

–Second interpretation

• Downloading?

– The process of a computer receiving information

–Depending upon connection speed, downloading can take from a few seconds to several minutes

p. 55 Next

The World Wide Web - URL• Unique address for a Web page

Fig. 2-6

The World Wide Web - Hyperlinks

• A link can be text or an image

• Text links are usually underlinedand in a differentcolor

Fig. 2-7

The World Wide Web – Search Engines

• Program used to find Web sites and Web pages by entering words or phrases called search text

Hits

Fig. 2-8

The World Wide Web – Subject Directory

• Search tool with organized set of topics and subtopics

The World Wide Web – Types of Web Sites

• Portal

• News

• Informational

• Business/Marketing

• Educational

• Entertainment

• Advocacy

• Blog

• Wiki

• Online Social Networks

• Content Aggregator

• Personal

p. 61

The World Wide Web

• Guidelines for evaluating the value of a Web site?

Fig. 2-12

The World Wide Web - Multimedia

• Text with other media elements

–Graphics• Gif/jpeg• thumbnails

–Animation

–Audio

–Video

–Virtual reality

p. 64 Fig. 2-13

The World Wide Web - Audio

• Music, speech, or any other sound

• Common Web audio file formats are AA, AAC, AIFF, ASF, MP3, WAV, WMA, RA, and QT

• Once downloaded, you can play (listen to) the contents of the files

p. 64 - 65 Fig. 2-14 Next

The World Wide Web - Streaming Audio

• Transfers data in a continuous and even flow

• Enables you to listen to the sound as it downloads to your computer

• Radio stations use streaming audio to broadcast over the Web

p. 64

The World Wide Web - Video

• Consists of full-motion images with soundplayed back at various speeds

• MPEG (Moving Pictures Experts Group) is popular video compressionstandard

p. 65

The World Wide Web – Virtual Reality

• Use of computers to simulate real or imagined environment

• Appears as a three dimensional (3-D) space

• Used for games and many practical applications

p. 65

The World Wide Web – Plug-ins

• Programs that extend the capability of a browser

• You can download many plug-ins at nocost from variousWeb sites

p. 66 Fig. 2-15

Web Publishing

• Development and maintenance of Web pages

Fig. 2-16

Business to business (B2B)Business providing goods and

services to other businesses

Consumer to consumer (C2C)One consumer sells directly to another

E-Commerce

p. 67 Fig.

Business to consumer (B2C)Sale of goods to general public

Other Internet Services – E-mail

• E-mail address

–Unique name that consists of a user name and domain name that identifies the user

• E-mail programs

–Microsoft Outlook

Fig. 2-19

Other Internet Services – E-mail Transmission

Fig. 2-20

Other Internet Services – Instant Messaging• MSN Messenger, etc.

Fig. 2-21

Other Internet Services - Chat

• Real-time typed conversation that takes place on a computer

• Chat room is location on server that permits users to discuss topics of interest

Fig. 2-22

Other Internet Services – Internet Telephony

• Enables users to speak to other users over the Internet using their computer

• Voice-over-IP (VoIP)

Fig. 2-23

Other Internet Services - FTP

• File Transfer Protocol

– Internet standard that permits you to upload and download files with other computers on the Internet

p. 72

Other Internet Services – Newsgroups & Forums

• Newsgroup

–Online area where users discuss a particular subject

–Need News Reader

• Message board (Forum)

– Type of discussion group

p. 71 Fig. 2-21 Next

Other Internet Services – Mailing List

• Group of e-mail addresses given a single name

• When a message is sent to the mailing list, everyone on the list receives the message

• To add your name to a mailing list you must subscribe to it; to remove your name you must unsubscribe

p. 73

Netiquette

Code of acceptable behaviors users should follow while on the Internet

p. 73

Golden Rule: Treat others as you would like them to treat you.