Transcript Chapter 8 - Mesa Community College

The Internet
MCC - CIS105
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Topics
Briefly describe the history of the Internet
Describe generally what an Internet
service provider does
Describe various types techniques used by
Internet search sites
Describe the various types of e-commerce
Describe how advertising is done on the
Internet
Describe what an intranet is and how a
business uses it
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The Internet and Services
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The Internet is a worldwide collection of
networks used to provide services such as…
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World Wide Web (WWW) – Websites
Email, Instant Messaging (IM)
Telephony – Voice over IP (VoIP)
Social network, newsgroups, discussion boards
File Transfer Protocol (FTP)
E-commerce – business transactions
For an overview of Making Use of the Web,
see pages 116-131 in the textbook
Discovering Computers 2008.
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Internet - many networks connected together
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Quick Time Line
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1969 - ARPANET
(Advanced Research Project Agency)
• Government sponsored the creation of a network.
• Scientists and military shared information.
• Network needed to provide alternative paths in
case part of the network was destroyed (war).
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1972 - E-mail capability added
1973 – The internet went international
1986 - National Science Foundation (NFS)
connected its large network, NSFnet,
to ARPANET.
1995 – NFS transferred service providing
role to private companies.
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Number of Users
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2002 – 567 million users
2003 – 780 million users
after 34 years (1969-2003)
Compare to…
2005 – US population = 295 million
Telephone took 91 years to reach
100 million users.
Television took 54 years to reach
100 million users.
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Number of Sites
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Another way to measure the growth is by
the number websites…
1969 – 4 sites
1971 – 20 sites
1979 – 200 sites
1989 – 100,000 sites
2000 – 72,000,000 sites
Why did it grow so much faster between
1989 and 2000?
One reason was the number Personal
Computers grew.
The other was the introduction of the
Graphical Browser…
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Graphical Web Browser
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A Browser is software used to navigate on the Internet
(Internet Explorer, Firefox, etc.).
1990 – Dr. Berners-Lee from Geneva wanted to make
the links from one website to another more dynamic
and easy using hyperlinks .
HyperText Markup Language (HTML) is the language
used to create web pages.
He described the links like a spider’s web.
Hence the name World Wide Web (WWW).
1992 – Marc Andreessen, college student at University
of Illinois and Eric J. Bina developed Mosaic – first
graphical web browser for multiple platforms.
• Graphical browser with hyperlinks and graphics.
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1993 – Andreessen and Ken McCarthy developed
Netscape.
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Internet Service Provider (ISP)
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An Internet Service Provider (ISP) provides the server
computer and connection software for companies and
individuals to connect to the Internet from their home
or business (Earthlink, Qwest, Cox, Hughes, etc).
Users at home need a modem to connect to their ISP.
Dialup – over phone lines
DSL (digital subscriber line) - over phone lines
Cable – coaxial and/or fiber optic
Fixed Wireless – slow to catch on – Tempe, Chandler
Mobile Wireless – cell phones, PDA’s, laptops
Satellite - Two modems (uplink and downlink)
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TCP / IP
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TCP/IP is the communication standard
(protocol) used on the Internet.
Transmission Control Protocol (TCP)
determines how messages are managed
• A message sent over the Internet is divided into
uniformly sized packets.
• Each packet is labeled with its destination
address.
• At the destination the message is reassembled
using the sequencing information.
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Internet Protocol (IP) determines how
communications software and equipment
transport messages.
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Uniform Resource Locator (URL)
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A URL is the complete and unique address of a
Web page.
Web page URL begins with http
• HyperText Transfer Protocol
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Domain name – address of site’s host computer
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Last part of domain name is called a top-level domain
Identifies country and/or purpose of organization
URL may include folder and specific filename.
http://www.sportsline.com/tennis/index.html
Protocol
Domain name
Path
Document name
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Registering a Domain Name
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Internet Corporation for Assigned
Names and Numbers (ICANN) is the
group that assigns and controls toplevel domain names.
Outside the United States, the domain
name also includes a country code.
For example - Australia: www.philips.com.au
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Domain Name mapped to IP Address
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An IP address is a unique Numeric Address for
each device on the Internet.
An IP address consists of four groups of numbers
separated with a period.
IP Address: http://64.233.167.99/
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Domain names are mapped to IP Addresses by a
Domain Name Server (DNS).
Domain names are meaningful and easier to
remember for users.
Domain: http://www.google.com/
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Search for IP Addresses (use WhoIs Lookup):
http://www.dnsstuff.com/
Error 404 – If domain name is not found in DNS.
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User called Helpdesk because their
“Internet connection was not working”.
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Turns out the user had set the invalid URL as their
homepage, so the error page was displayed every
time they opened their browser .
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Web Browser Limitation
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Browsers can process and display
several formats such as HTML, gif,
jpeg, JavaScript, etc.
However, browsers cannot handle
everything.
Functionally is increased by using:
• Plug-ins
• Helpers
• Web Programming
• See next few slides…
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Plug-ins / Helpers
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Software that increases browser functionality
Most downloaded from their own Web sites
• Once downloaded and installed, it appears as if
the browser can handle the new features.
• The features are being processed by the plug-ins.
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Most enhance a site’s audio/visual
experience
• Flash and QuickTime Players permit viewing sites
that include quality animation
• Adobe Acrobat Reader displays and prints
documents created in Portable Document Format
(PDF) format
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Web Page Programs
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Small programs can be downloaded to run in your
browser
• Allow dynamic interaction and dynamic data
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Scripting languages (Client Side)
• Instructions to be interpreted and executed by your browser
• JavaScript and VBScript are most common
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Programming Languages (Client and Server Side)
• Java applets and ActiveX controls are most common
• Scripting languages that can call programs stored on the server
include ASP, JSP, PHP, Perl, and others.
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May require additional software be installed such as
Java Runtime Environment (JRE)
Cookies – information that a program stores on your
hard disk so that it can remember something about you
or your process at a later time.
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Searching the Internet
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Search Engine
• Lets a user specify simple or complex search criteria.
• Search engine then searches the entries in it’s database and
returns a list of sites that matches the criteria.
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• Uses spider software to build database.
• Spiders “crawl” throughout websites collecting
information – can even find “hidden” files.
Trivia - Google was supposed to be Googol, the number
1 followed by 100 zeros
Internet directory – list is developed by humans
rather than a spider, so entries are very selective
(yellowpages).
www.mc.maricopa.edu/dept/d07/cis105/searchengines.html
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Evaluating the Information
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Author
Sources
Server (who provides)
Objectivity (balanced?)
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Purpose
Accuracy
Currency
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Email
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Basic Electronic Mail (email) needs…
• A server with email services
• Users need an account
• Need a client application to access the server
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SPAM is unsolicited e-mail.
• The term spam is said to derive from a famous Monty
Python sketch.
• SPAM is a trademarked Hormel meat product.
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Phishing is e-mail fraud where the perpetrator
sends out legitimate-looking e-mails that appear to
come from well known and trustworthy Web sites
in an attempt to gather personal and financial
information from the recipient (see next slide).
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Phishing Examples
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Other Communication Services
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Social Networks – myspace, facebook
NewsGroups – allows posting and reading
of messages to a group for everyone
to read (discussion board).
IRC: Internet Relay Chat
• Text Chatting in Real Time
to a group, like a party line
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Instant Messaging – to one person
Internet Telephony: Real-Time Voice and Video
VoIP – Voice over IP (Internet Protocol)
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Internet Phone Services (Vonage)
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File Transfer Protocol (FTP)
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Allows for upload and download of files.
Anonymous FTP
• No username or password required.
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Uploading will most likely require a
username and password.
Some files are compressed into an archive
using a program like WinZip, so the files
need to be expanded or extracted after
downloading.
• Self-extracting is an executable that is doubleclicked to begin file extraction.
• If not self-extracting, will need a compatible
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program to extract files.
Homepage / Portal
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Homepage is the first page displayed when
the browser is opened
A portal is a website that is supposed to be
set as your homepage.
Webpage can be personalized so
information you are interested in is
displayed – stock market, sports, weather
May advertise referrals to businesses
Yahoo, Google, MySpace, etc.
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Internet
Advertising
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Many advertisements on Web sites are banner ads
Pop-over ads open a new window on top of your
current window
Pop-under ads open a new window underneath
your current window
All this advertising is to increase electronic
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commerce…
Electronic Commerce
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B2B (Business to Business)
B2C (Business to Consumer)
C2C (Consumer to Consumer)
• Ebay.com – watch for fraud
• CraigsList.org – Free classified ads
Payments – SSL – Secure Sockets Layer
ePal is a 3rd party that handles payments.
Internet Taxes Freedom Act
• No sales tax on out-of-state sales
• But usually need to pay shipping
Privacy – companies must provide
you their privacy policy.
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Intranets & Extranets
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An Intranet is a private Internet-like network.
Uses the same technology as used for an Internet site.
Internal – only computers on the same network may
access services – ie: Employee Information
Extranets allow selected customers and suppliers to
have access to a company’s intranet.
EDI – Electronic Data Interchange
• Standard format to exchange data
(ie: College transcripts, financial data)
Can usually identify an Intranet/Extranet when a
username and password is required to enter.
Access can be restricted using firewalls and IP addresses.
• Firewalls – hardware and software
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Want to Learn More?
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CIS133DA – Internet / Web Dev
CIS235 – e-commerce
Certificate of Completion or
Two-Year Degree in
Web Technology.
www.mc.maricopa.edu/dept/d07/degrees.html
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