Transcript Chapter 8: The Internet: A resource for all of us

The Internet at Home and
in the Workplace
Chapter 8
Objectives
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Briefly describe the history of the Internet
Explain what is needed to get on the
Internet
Describe generally what an Internet
service provider does
Describe the rudimentary functions of a
browser
Describe how to search the Internet
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Objectives
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List and describe the non-Web services of
the Internet
Describe the various types of e-commerce
Discuss e-commerce payments and taxes
Describe how advertising is done on the
Internet
Describe what an intranet is and how a
business uses it
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History of the Internet
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Government and Universities over 30 years
Who’s connected today?
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Individuals
Educational institutions
Government/Military/Police
Research
Medical
Businesses
Everyone!
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The Early Years
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1969 – US Department of Defense and Rand
Corporation
Origins
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Cold War – fear that a bomb could demolish computing
capabilities
Several computers, geographically dispersed, networked
together
Plan – if one computer was disabled, others could carry on
using alternative communication routes
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The Early Years
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Many WANs and LANs were installed, but
machines on the WANs could not access
information on the LANs..
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Remote access was separated from local access
A single cohesive network was desirable.
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The Early Years
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US Department of Defense had a similar
scenario – lots of autonomous networks that
could not interoperate
The DoD funded network research in the
early ’70s through (D)ARPA creating various
network technologies, including a research
WAN called ARPANET.
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The Early Years
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ARPANET allowed researchers the
opportunity to build a working test-bed for
networking ideas.
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Solved incompatibility issues
Solved interoperability issues
Created an internetwork of LANs and the WANs
The Internet is born
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The Early Years
G2
G1
UCB
LAN
UCLA
LAN
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ARPANET
Backbone
G4
G3
MIT
LAN
DARPA
LAN
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The Early Years…
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Internet Software
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Internet Protocol (IP)
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Transmission Control Protocol (TCP)
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Provides basic communication
Handles the addressing and routing
Provides services for applications to communicate
Packetizes message, reassembles message at the
destination
The “TCP/IP Internet Protocol Suite”
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aka TCP/IP
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The Early Years
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ARAPA placed the research and software into
the public domain.
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All information was freely available to any person
or vendor, allowing them to create devices or
networks that would interoperate with the Internet
technology.
Improvements were documented and made
publicly available.
This philosophy is called an Open System
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The Early Years
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Internet documentation
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On-line and accessible from the Internet
Reports for improvements to the Internet were initially a
two step process
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Request for comments (RFC) went out first
Internet Engineering Note came out with the comments
as the final report.
Today the RFC remains as the definitive documentation for
the Internet
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On-line at www.faqs.org/rfcs/
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Also www.ietf.org/rfc.html
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The Early Years
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The UNIX operating system
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Built at Bell Labs in the early ’70s
UNIX given to universities to study
UC Berkeley team added LAN software
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Distributed to others via the Berkeley Software
Distribution (BSD) and became known as BSD UNIX
(The ancestor of today’s Free BSD)
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The Early Years
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ARPA negotiated with UCB to add the TCP/IP
suite to the BSD UNIX release.
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Gave large number of universities access to
study networking, and deploy it in their
departments.
1982 the US Military chose the Internet as its
primary communication system.
1983 the ARPANET began running TCP/IP
exclusively.
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The Early Years
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Incredible growth from day one..
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In 1982 ~200 machines were connected
By 1983 the number had doubled
With growth comes the problems..
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Static lists of machines need updated
Limited memory space …
Software updates..
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The Early Years
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The Computer Science Network (CSNET)
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Sponsored by NSF in early `80s
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Goal was to connect every Computer Scientist in the
country over one network.
CSNET was deployed using TCP/IP and the Internet
By mid 1980s most major university and research labs
were connected to the Internet
Graduate students began to investigate the details of
these new technologies, and include them in their
research topics.
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Developed new applications
Extended the technology
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The Early Years
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The IAB (Internet Activities Board)
(Now known as the Internet Architecture
Board)
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Original controlling body to coordinate TCP/IP
research and Internet development.
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Chairman – Internet Architect
RFC Editor
Formed volunteer task forces to solve problems
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Task forces generated new RFCs
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The Early Years
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The IETF (Internet Engineering Task Force)
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Originally chartered for short-term Internet
development.
Now is responsible for most of the Internet
technical development
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Working groups meet and create the RFCs
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Manet, ipsec, tcp…
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The Early Years
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NSFNET
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NSF recognized the importance of the Internet to
the scientific community.
Interconnected the supercomputer centers
around the US with a TCP/IP WAN
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Proved useful, but small
NSF looked for ways to improve the ARPA Internet
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The Early Years
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The NSFNET Backbone
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1988 WAN established as main backbone of the
Internet
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MCI – long distance transmission lines
IBM – dedicated computers and software
MERIT – network operation
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The Early Years
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The ANS Backbone (Advanced Networks and
Services)
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Consortium of MCI, IBM & MERIT
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Allowed the government to begin privatization of the
Internet
1992 – WAN was built to serve as the Internet
backbone
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ANSNET, 30 times NSFNET capacity
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The Early Years
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Exponential growth …….
80000000
70000000
60000000
50000000
40000000
30000000
20000000
Computers
Connected
10000000
0
1983 1987 1991 1995 1999
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Growth of Internet
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Growth in host computers
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72 million in 2000
162 million in 2002
Growth in users worldwide
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567 million in 2002
780 million projected in 2003
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The Early Years
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By 1999, the Internet was growing so fast that,
on average, a computer was added to the
Internet every second – and the rate continues
to increase.
An interesting fact:
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At any time from 1983 through 1999, approximately
half the growth of the Internet occurred in the previous
12 months…
So, after you have been “on” the Internet for
only one year, you will have had more
experience than half the other users….
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The Early Years
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Growth – Good and Bad
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Good for vendors
Bad for the IETF
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Predictions of imminent collapse
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March 1993, Summer ’97
Technology improvements have kept up with
bandwidth and switching speeds required.
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The Early Years
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The Hard limit – Address space
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The IP protocol is limited to a number contained in
4 bytes (32 bits)…
Byte 3
Byte 2
Byte 1
Byte 0
•This limits the number of possibilities to 232 = 4,294,967,296
•There are solutions – IPv6
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The Early Years
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Summary
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The Internet began as an ARPA research project.
The TCP/IP protocol software was developed to
make the Internet operational.
The Internet is an Open System, with the
technology freely available to all.
The Internet documentation is available on-line in
the form of reports known as RFCs.
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The Early Years
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Summary (continued)
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BSD UNIX distributed TCP/IP suite freely to
universities in the early 80s
1982 US Military adopted TCP/IP as primary
communication standard
Exponential growth from its inception
IAB formed to coordinate development
IETF - major technical development body
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Working groups
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The Early Years
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Summary (Continued)
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1988 – NSFNET Backbone
1992 – Privatization (ANSNET)
Exponential growth from its inception
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Half of the users today have been there less than one
year……
IP Address 32 bit limitation
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Tim Berners-Lee
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Worked at CERN lab in Geneva
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Thought his work would be easier if he
could link to colleagues’ computers
Envisioned a network of computers
much like a spider web
Used links to transfer data from one site
to another location
CERN site considered the birthplace of
the World Wide Web
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Marc Andreessen
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Developed the first graphical
browser
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Called Mosaic
Led to Netscape Navigator
Could display attractive images
and a graphical interface
permitting users to click on
pictures as well as text
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Internet Links
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A link on a Web site is
easy to see
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Either underlined and
colored text or an icon
Clicking the link transfers
data from that site to the
user’s computer
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Browser
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Interface software used to
explore the Internet
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Early browsers were text-only
Mosaic was the first graphical
browser
Graphical browsers combine
ease of links with attractive
graphical interface
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A Little About the Technology
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A message sent over the Internet is divided into
uniformly sized packets
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Each packet labeled with its destination address
Transmission Control Protocol/Internet Protocol
(TCP/IP)
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TCP creates and reassembles packets
IP handles addressing
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Ensures that packets are routed to their ultimate
destination
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The Internet Service Provider and the
Browser
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An Internet service provider
(ISP) provides the server
computer and software to
connect to the Internet
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Online service, such as America
Online, includes Internet
access, Internet service, and a
browser
When you connect to the
Internet, the browser displays
a home page
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Menus and Buttons
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Menu – a series of choices normally laid out
across the top of the screen
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Called pull-down menus
Each initial choice gives lower-level choices
Buttons can be used to invoke commands
Screen tip – a small text message that
appears when you rest the cursor over a
button
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Uniform Resource Locator (URL)
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The complete, unique address of a Web page
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Web page URL begins with http
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HyperText Transfer Protocol – allows communication
by using links to transfer data between sites
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 or purpose of organization
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URL
Uniform Resource Locator
http://domain-name.top-level-domain/last-section
Unique address of a web page or file on the
Internet
 Case-sensitive
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Processing Requests
URL
 User
enters a URL
 User computer sends request to the ISP
server
 ISP server sends request across networks of
TCP/IP computers
 Destination site is reached
 Content is transmitted back to your computer
(process in reverse)
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Plug-ins
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Software that increases browser functionality
Most downloaded from their own Web sites
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Once downloaded and installed, the browser can handle
the new features
Most enhance a site’s audio-video experience
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Shockwave permits viewing sites that include quality
animation
Adobe Acrobat Reader displays and prints documents
created in Portable Document Format (PDF) form
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Web Page Programs
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Small programs can be downloaded to run in your
browser
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Allow Web pages to perform many tasks
Allow dynamic interaction
Come in several forms
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Scripting languages
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Produce instructions to be interpreted and executed by your
browser
JavaScript and VBScript are most common
Programs embedded in Web page
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Java applets and ActiveX controls are most common
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Programming
Java
 Write software that is machine independent
 Programming language
Dancing icons
 Sound clips
 Flashing messages
 Banners that scroll
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Applets – Permits dynamic web pages
Display animations
 Receive input
 Perform calculations
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Programming
ActiveX Controls
Capabilities similar to Java
Browser must be enabled to support applets /
ActiveX Controls
Security issues
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Wireless Internet Access
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Use handheld devices such as pagers,
PDAs, or pocket computers to access the
Internet
Wireless Application Protocol (WAP) –
convert Web pages into a format more
compatible with limited capabilities of
handheld devices
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Wireless Internet Access
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Supports mobile handheld devices
Text pagers
 PDAs
 Pocket computers
 Web-enabled cellular phones
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Applications
E-mail
 Checking weather
 Making airline reservations
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Searching the Internet
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Search Engine – lets a user
specify search terms
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Search engine builds database of
sites that match those terms
Uses spider software (or bots) to
build database
Metasearch – searches search
engines and builds
comprehensive list
Internet directory – database is
developed by human researchers
rather than spider
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Processing Requests: Search Engine
Database
Request same search using different engines
yields different results
 Databases built independently
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Size
Content
Search methodology
Pages may be submitted by the owner
Metasearch – automatically puts the same request
to several search engines
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Processing Requests: Search
Engine Limitations
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Index only a fraction of the Web
Approximately 20% to 33% of sites
More web pages added daily
Solution
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Same request to several search engines
Metasearch
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Not Perfect
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Unregulated
Useless web sites
Misinformation and misstatements on web
sites
Concern over government censorship
Security & Privacy Issues
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Newsgroups
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Usenet – an informal network of computers
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Allows posting and reading of messages
Typically focuses on specific topics
Requires a newsreader
Some are moderated
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Messages sent to a moderator, who determines whether
the message is appropriate
Prevents users from attacking other members and
prevents inappropriate material from being posted
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File Transfer Protocol (FTP)
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A protocol for transferring files among
computers
FTP servers maintain collections of
downloadable files
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Downloading can often be done anonymously,
without logging in
Many FTP servers can be accessed through
Web browser
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Telnet
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A protocol that allows remote users to log
onto a host computer
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Users use their own PCs
Users log in over the Internet
Users’ experience is the same as if they were
sitting at the host computer’s local terminal
Remote user typically has to have a user ID
and password
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E-Mail
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The most commonly used feature of the
Internet
Network provides mail server
E-mail client software on your computer
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Mail Server
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Collects and stores messages in mailbox
E-mail address consists of user name,
followed by @ symbol, then domain name of
mail server
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E-Mail Client Software
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Allows you to manage your e-mail messages
Features
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Address books
The ability to attach files
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Some e-mail servers block all attached files
Filters
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Direct incoming e-mail to specific folders
Block spam
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IRC: Internet Relay Chat
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Not Perfect: Social Issues
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Behavior problems
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Who is out there?
What are they doing?
Netiquette
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Suggestions for appropriate behavior
Example: TYPING IN CAPS is shouting
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The World of E-Commerce
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Electronic commerce - buying and selling
over the Internet
Three forms
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Business-to-consumer (B2C)
Business-to-business (B2B)
Consumer-to-consumer (C2C)
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Business-to-Consumer
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Businesses selling goods to consumers
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Has received the most media attention
Estimates of U.S. online sales
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$48 billion in 2002
Projected $130 billion by 2006
Several models
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Pure-play
Bricks-and-clicks
Flips-and-clicks
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Pure-Play Model
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Companies operate
exclusively over the Internet
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Some have their own
warehouses
Others relay orders to
manufacturer or wholesaler
Examples include
Amazon.com and etoys.com
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Bricks-and-Clicks Model
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Traditional retail outlets that
have established a Web
site
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Name is a play on “bricks and
mortar”
Examples include J.C.
Penney and Macys
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Well-known brand names
Loyal customer base
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Flips-and-Clicks Model
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Traditional mail-order retailers
that have established Web sites
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Catalogs placed on Web sites
Allow customers to replace
flipping pages with clicking links
and icons
Examples include L.L. Bean and
Land’s End
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Allows retailer to reach many
more customers
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Business-to-Business
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Businesses selling to other businesses
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Has not received much media attention
Estimates of worldwide sales
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$1.9 trillion in 2002
Projected $8.5 trillion by 2005
Internet exchanges are being developed to
provide electronic marketplaces
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Internet Exchanges
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Create a marketplace
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Advantages
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Bring together many buyers and
sellers
Reduced costs of procurement
(purchasing)
The ability to consider many
suppliers
Potential concerns
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Security
Antitrust concerns (possible
price-fixing)
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Consumer-to-Consumer
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Takes place on online
auction sites
Make buying and selling
unique items easy
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Your item is visible to anyone
in the world with an Internet
connection
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Payments and Taxes
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E-commerce payments
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Some people are leery of submitting credit card
information online
Secure Sockets Layer (SSL) protocol provides a secure
way to make online payments
E-commerce taxes
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Internet Tax Freedom Act provides tax relief on Internet
commerce
Commission studies the effects of taxation of Internet
commerce
Act set to expire in 2005
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Internet Portals
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Your first stop on the Internet
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Provide personalization to users
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Site is customized based on
information you provide
Encourages you to visit the site
often
Provide referrals to other
businesses
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Site contains links to affiliate
sites
If you click on an affiliate site and
make a purchase, the portal
receives a percentage of the sale
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Internet Advertising
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Many advertisements on Web
sites are banner ads
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Originally in the shape of a long
rectangle
Require the user to leave the
current site
Other ad types
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Pop-over ads open a new
window on top of your current
window
Pop-under ads open a new
window underneath your current
window
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Intranets
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A private Internet-like network
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Internal to a certain company
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Extranets allow selected customers and suppliers to
have access to a company’s intranet
Easy to set up
Offer many potential uses
Can be linked to the Internet
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Setting up an Intranet
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Easy to set up
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Most organizations already have a local area
network
Hardware requirements
Software requirements
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Hardware Requirements
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Server computer handles requests
Computer for storing databases and other
documents
Client computers needed for access to the
Intranet
TCP/IP protocols must be in place
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Software Requirements
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Server must be able to process requests from
other computers
Server must be able to retrieve data from
computers that store it
Each access computer needs a browser
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Uses of Intranets
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Users can
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Retrieve information such as benefits information
and job openings
Submit vacation requests, applications for open
positions, etc.
Employers can post employee handbooks,
corporate policies, and other information in a
central location
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Virtual Private Network
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Technology that uses the Internet as a
channel for private data communication
Uses tunneling technology
Offers many benefits over a private network

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Much cheaper than dedicated lines
Data is secure
Turns remote network administration over to ISP
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Tunneling
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Also called encapsulation
Transfers data between two similar networks over
an intermediate network
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Data packets follow Point-to-Point Tunneling Protocol
(PPTP)
Data embedded in TCP/IP packets carried by the Internet
Data packets are encoded before encapsulation
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When received, they are separated and returned to their
original format
Provides security for data packets
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