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Lecture 03 Going Online Topics Basics Connecting to the Internet World Wide Web Internet Applications Internet Ethics © 2005 Prentice-Hall, Inc. Slide 1 Basics Internet: worldwide collection of inter connected net works; Computers are no longer lonely

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lecture 03 going online

Lecture 03 Going Online



Connecting to the Internet

World Wide Web

Internet Applications

Internet Ethics

© 2005 Prentice-Hall, Inc.

Slide 1



Internet: worldwide collection of interconnected networks; Computers are no longer lonely

ARPANET (1969): network for scientists that evolved into the Internet

Internet backbone: major communications lines and nodes to which thousands of hosts are connected

© 2005 Prentice-Hall, Inc.

Slide 2



No one group controls the Internet, but some organizations coordinate Internet activities

The Internet Society to assure the open development, evolution, and use of the Internet

ICANN (Internet Corporation for Assigned Names and Numbers): responsible for coordinating the assignment and allocation of domain names and internet addresses

W3C (World Wide Web Consortium): create and maintain technical specification to keep pace with changing technologies used on the Internet

© 2005 Prentice-Hall, Inc.

Slide 3

connecting to the internet

Connecting to the Internet

Bandwidth: amount of information that can be sent over the channel, in bps (bits per second)

Broadband – high bandwidth

Narrowband – low bandwidth

© 2005 Prentice-Hall, Inc.

Slide 5

connecting to the internet5

Connecting to the Internet


Dialup service

Phone line


56 Kbps

© 2005 Prentice-Hall, Inc.

Slide 8

connecting to the internet6

Connecting to the Internet



TV cable

LAN PC card

Cable modem

1 M~10 Mbps

DSL (Digital Subscriber Line)

Phone line

LAN PC card

ADSL modem

Upstream rate: 128Kbps~1.5Mbps

Downstream rate: 1.5M~9Mbps

© 2005 Prentice-Hall, Inc.

Slide 9

connecting to the internet7

Connecting to the Internet

Broadband (cont)


Satellite disc

Satellite modem

LAN PC card

Upstream rate:56Kbps~1.5Mbps

Downstream rate: 400Kbps~1.5Mbps

Latency – time lag in communication


AP (Access Points)

Wireless LAN PC card

Wi-Fi (Wireless Fidelity) standard

Wireless-B (IEEE 802.11b)/11Mbps/300ft

Wireless-A (IEEE 802.11b)/54Mbps/50ft

Wireless-G (IEEE 802.11g)/54Mbps/Far better than A

© 2005 Prentice-Hall, Inc.

Slide 9

connecting to the internet8

Connecting to the Internet

ISP (Internet service provider)

Communication software (Dialup/ DSL)

Hinet/ Seednet

Information service gateway

Communication software (link to the information network of AOL)

user ID and password

AOL (America OnLine)/ MSN

Direct LAN connection

T-1 line (1.544Mbps)

T-3 line (44.736Mbps)

© 2005 Prentice-Hall, Inc.

Slide 10

connecting to the internet9

Connecting to the Internet

Protocol TCP/IP (Transmission Control Protocol/Internet Protocol)

Protocol: set of rules for how computers communicate, defining message format and interaction patterns

Packet: the part of a message that contains the data and the address the message is being sent to

Packet switching

TCP dividing files into packets

IP routing each packet to destination

© 2005 Prentice-Hall, Inc.

Slide 11

connecting to the internet10

Connecting to the Internet

IP (Internet Protocol) address

Identify each device attached to the Internet by numbers

Four numbers, each 0~255, separated by periods, e.g.,

Fixed vs. Dynamic IP address

Domain names

Identify each device attached to the Internet by symbols, e.g., ailab2.et.ntust.edu.tw

top-level domains: denote affiliation


DNS (Domain name system)

Translate domain names to IP addresses

© 2005 Prentice-Hall, Inc.

Slide 12

connecting to the internet11

Connecting to the Internet

URL (Uniform Resource Locator)

Identify each resource on the Internet, e.g., ftp://ailab2.et.ntust.edu.tw/www/InfoTech/Lecture01.ppt

Four parts

access method: ftp

Domain name: ailab2.et.ntust.edu.tw

Path name: www/InfoTech

Resouce: Lecture01.ppt

© 2005 Prentice-Hall, Inc.

Slide 12

connecting to the internet12

Connecting to the Internet

Client program runs on user’s computer

Internet browser/ FTPPro

Server program – runs on server computer

© 2005 Prentice-Hall, Inc.

Slide 14

connecting to the internet13

Connecting to the Internet

More devices to connect to the Internet

televisions/ Freezer

video game consoles

PDA/ cellular phones

Internet appliances

A specific device to go online at anytime, any place

© 2005 Prentice-Hall, Inc.

Slide 13

world wide web

World Wide Web

WWW, the Web (World Wide Web)


Web servers

Containing webpages and server programs

Home page – first page you see at a site


A document containing multimedia data and hyperlinks

Hyperlinks – allow user to click on an icon and be taken to other resources on the Internet

Document structure is specified by HTML/ XML/…

© 2005 Prentice-Hall, Inc.

Slide 17

world wide web15

World Wide Web

WWW, the Web (World Wide Web)


A client program which interprets a webpage and interacts with the Web server

IE/ Netscape/ KKman/ Mozilla Firefox

HTTP (Hypertext Transfer Protocol)

A protocol for client and server programs to communicate

© 2005 Prentice-Hall, Inc.

Slide 17

world wide web16

World Wide Web

HTML (HyperText Markup Language)

A language to format a webpage using paired tags,e.g., <i> </i>; <a> </a>

Define howeach multimedia component in a webpage is displayed

XML (eXtensible Markup Language)

A meta-language to define the language for formatting a webpage

© 2005 Prentice-Hall, Inc.

Slide 12

world wide web17

World Wide Web

Browser Plug-ins

Software modules that are integrated into a browser to add flexibility

Animation/ multimedia displays

Applets or ActiveX controls

Streaming audio and video

Media is presented continuously instead of being downloaded

Java RTE/ Flash player/ Window Media Player/ RealJukebox/ QuickTime/iPIX Movies/ Acrobat Reader/ Liquid Player

© 2005 Prentice-Hall, Inc.

Slide 18

world wide web18

World Wide Web

Common operations of Browser

Back: go to previous page

Forward: go to next page

Stop: ends transmission

Refresh: reload Web page

Bookmarks (Favorites): have browser remember favorite sites

Location bar: where user enters URL

© 2005 Prentice-Hall, Inc.

Slide 21

world wide web19

World Wide Web

Finding information on the Web

Browsing: just looking around portals

Portal: a site that provides a number of services

Classified Index database

Yahoo/ Yam/ Excite..

Searching: trying to find specific information by using search engines

Search Engine: a program that goes to the Internet or within a Website to search for webpages users need

Google/ Yahoo/ Excite/ MSN/Hotbot/ Ask Jeeves/ Infoseek/ AltaVista/ Metacrawler/

© 2005 Prentice-Hall, Inc.

Slide 26

world wide web20

World Wide Web

Tips for searching the Net

Read the rules for each search engine

Try multiple search engines

Follow hyperlinks

Choose search terms carefully

Be persistent

Use FAQ (Frequently Asked Questions)

lists answers to questions asked often at a particular site

© 2005 Prentice-Hall, Inc.

Slide 29

internet applications

Internet Applications

Resource retrieval


Web server


multimedia documents




Integration of Internet applications, e.g., FTP, email, ..

© 2005 Prentice-Hall, Inc.

Slide 32

internet applications22

Internet Applications

Resource retrieval (cont)

FTP (File Transfer Protocol)

FTP server

Easily download/upload files

Anonymous FTP sites


Help a client program to gather mp3 and other audio files from Internet music resources

© 2005 Prentice-Hall, Inc.

Slide 33

internet applications23

Internet Applications



e-mail server

file attachments


Mailing lists or listservs

push technology – information is delivered automatically from the server to client programs


Instant messaging (Whiteboarding)

© 2005 Prentice-Hall, Inc.

Slide 34

internet ethics

Internet Ethics


Using all capital letters is considered SHOUTING

Never send unsolicited e-mail (spam)

Consider your audience when forwarding Internet content

© 2005 Prentice-Hall, Inc.

Slide 36

internet ethics25

Internet Ethics

Netiquette (cont)

Never reveal others’ personal information

Be patient with people who are justgetting online (newbies)

Don’t comment on others’ spelling,grammar, or punctuation

© 2005 Prentice-Hall, Inc.

Slide 37

internet ethics26

Internet Ethics

Netiquette (cont)

Keep private communications private

Consider e-mail attachment sizebefore sending to someone (using dialup)

Confirm virus warnings before forwarding

Use an anti-virus program

© 2005 Prentice-Hall, Inc.

Slide 38

internet ethics27

Internet Ethics

Shady side of the Internet

Hackers and crackers

Hate mongers


Filtering programs



© 2005 Prentice-Hall, Inc.

Slide 40