Transcript Chapter 7

The Internet, Intranets, and
Extranets
Chapter 7
Chapter 7, The Internet, Intranets, and Extranets,
covers the Internet and its use and effects.
After studying chapter 7, you should be able to
address the learning objectives described in the next
3 slides.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 2
Learning Objectives
Define how the Internet works
Describe the services associated with
the Internet
Describe the World Wide Web
Define the terms intranet and extranet
and discuss how organizations use
them
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 3
The Internet is relatively young, and its services and
features are evolving. Technologies pioneered by the
Internet are currently being used by organizations to
create intranets and extranets.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 4
Learning Objectives
Identify who is using the Web to
conduct business
Discuss some pros and cons of Web
shopping
Identify several issues associated with
the use of networks
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 5
Before the Internet is routinely used for business, many
issues, such as those related to service, privacy, and
security, must be resolved.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 6
Learning Objectives
Outline a process for creating web
pages
Describe Java and its potential impact
on the software world
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 7
The Internet is impacting business and individuals. It’s
important to understand some of its underlying
technologies, such as web page creation and Java.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 8
Use and Functioning of the
Internet
The Internet is an international collection of computer
networks connected together by routers. Devices use
specific protocols to communicate over the Internet and
individuals and business access it through Internet
Service Providers, or ISPs.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 10
Use and Functioning of the
Internet
Fig 7.1
Figure 7.1 shows how the Internet is composed of
many networks. These networks are connected
together using routers.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 12
Use and Functioning of the
Internet
Interconnected networks
Global though US is the largest user
Internet Protocol (IP)
Research for a faster Internet
 Internet2 (I2)
 Next Generation Internet (NGI)
 Corporate efforts
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 13
The United States is the largest user of the Internet today,
although use by other nations is increasing rapidly. There
is no single point of registration and control for the
network; it has no central infrastructure. The many
networks communicate by using the Internet Protocol,
common standards for routing messages.
Universities, corporations, and the government are
conducting research to speed Internet access. The Next
Generation Internet, or Internet2, is probably the most
publicized effort.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 14
How the Internet Works
Hosts
Routers forward packets to other
networks
Internet Protocol Stack (TCP/IP)
Internet Protocol (IP)
 Transport Control Protocol (TCP)

Backbones
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 15
Computers on the Internet, whether mainframes or PCs,
are called hosts. Routers forward messages in pieces,
called packets, on the Internet, from one network to
another, using the Internet Protocol. When a host sends a
message to a computer on a different network, it goes
first to a router. The router sends it to another network,
where another router may pass it on. All networks
connected to the Internet use the Internet Protocol stack,
also called TCP/IP. IP is the network layer protocol that
helps route packets from one network to another.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 16
TCP, Transport Control Protocol, is one of several other
protocols included in the Internet Protocol stack used
by most hosts on the Internet.
Networks using TCP/IP standards connect to one of the
Internet’s fast, long distance communications links, a
backbone, to communicate with other networks on the
Internet.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 17
How the Internet Works
Uniform Resource Locator (URL)
http://www.whitehouse.gov
World Wide Web
Hypertext
transfer protocol
Chapter 7
Domain category
Host Network Name
Principles of Information Systems,
Fifth Edition
Slide 18
Each host on the Internet has been assigned a unique
address to distinguish it from other computers on the
Internet. The address is a long sequence of numbers –
easy for computers and routers to process, but hard for
people. Unique logical names, called URLs, or
uniform resource locators, are also assigned to
correspond with the numeric address, making it easier
for people to remember.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 19
Consider the URL for the White House,
http://www.whitehouse.gov/. The “http” signifies a
specific Internet protocol used by most web browser and
web server software. The “www” means this site is part
of the “World Wide Web”, one of several Internet
services. “Whitehouse.gov” is the domain name.
Domain names follow specific rules. Dots separate the
components of the address, and there will be at least two
components, as in whitehouse.gov.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 20
With the exception of most US domain names, the
rightmost part is typically a country designator. For
example, the National Library of Australia has the
URL http://www.nla.gov.au/, where “au” designates
Australia. The leftmost part of the domain name
identifies the host network, such as “nla” or
“whitehouse”. The rightmost part of a US domain
name (and the part next to the country code for a nonUS name) designates the category, or type, of the site.
Here, the category is “gov”, for government.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 21
Table 7.1
Table 7.1 shows various top-level domain extensions.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 23
Accessing the Internet
Fig 7.2
As shown in Figure 7.2, there are 3 ways to access the
Internet. First, you can connect to the Internet using a
LAN server. This is often found in businesses or
schools where individual PCs are connected to Local
Area Networks, or LANs. One of the nodes on the
LAN is a server connected to the Internet, generally at
56 kbps or faster. Using your residential phone
line,you can connect to and Internet Service Provider
using SLIP or PPP, 2 data link layer protocols used for
dial-up Internet access. You can also connect from a
home phone using an on-line service provider such as
America Online or Microsoft Network.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 25
The latter two ways access the Internet at speeds lower
than 56 kilobits per seconds.
In many parts of the country, residential Internet access is
also available through cable modems, satellite, ISDN or
DSL services. These connections are typically faster than
dialing up an ISP using your normal phone service.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 26
Internet Service Providers
(ISPs)
Provide Internet access to account
holders
Monthly fee varies
Some are free
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 27
An ISP is any company that provides internet access to
individuals or organizations. ISPs don’t normally offer
services as extensive as those on on-line services such as
America Online, although ISP’s offerings are continually
becoming more extensive. Some ISPs, such as Netzero,
offer no-fee Internet access to subscribers. Free ISPs
typically have more ads on their websites than do others,
since they earn income from the ads.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 28
Table 7.2
Table 7.2 shows a representative list of ISPs which
charge customers a monthly fee. Often, fee-based ISPs,
provide faster connections to the Internet, since free ISPs
are often used by numerous people.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 30
Internet Services
The Internet has impacted business and individuals
because of the many uses and services it provides.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 32
Table 7.3
Table 7.3 summarizes services offered on the Internet.
This list is continually expanding as the Internet is put to
new uses. We’ll discuss some of the more frequently
used services in the next few slides.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 34
Internet Services
E-mail (Electronic mail)
Can include images, attachments, or
HTML
 Routed by gateways and routers

Telnet: remote login
FTP: file transfer
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 35
Since e-mail travels across multiple networks, gateways
may be used to translate the format of an e-mail message
into one the next network can understand. Routers and
gateways use the address on the “to” line of the e-mail
message to send the message to networks that get it to its
destination. E-mail has changed the way people
communicate. Unlike using the telephone, e-mail
communications can be handled on your schedule, at
your pace.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 36
Telnet, or remote login, is a terminal emulation protocol
that lets you log on to remote computers on the Internet
& access public files. FTP, or file transfer protocol, is a
protocol for transferring files between computers on the
Internet. FTP allows you to copy files, such as software,
from a remote computer. Before the existence of the
world wide web, Telnet and FTP were the main way to
access resources on the Internet.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 37
Internet Services
Table 7.4
A Usenet is a virtual asynchronous forum for an
electronic group, or Newsgroup, to share messages
about particular topics. Users send e-mail to the Usenet
server, where all e-mail is stored and can be read by all
group members. Representative Usenet Newsgroups,
such as those focusing on Elvis, the LA Lakers, or
music, are listed in Table 7.4. Some newsgroups are
moderated; that is, a person screens incoming email
before it is posted to be sure it is appropriate. However,
many are unmoderated.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 39
Internet Services
Chat rooms: allow interactive
conversations
Instant Messaging: online, real-time
communication over the Internet
Videoconferencing
Internet phone
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 40
Chat rooms allow two or more people to “converse”
interactively over the Internet. Most often the
conversation is typed; however, in some chat rooms,
with the appropriate equipment, voice chat is possible.
Instant messaging allows individuals to interact online,
just as chat rooms allow real-time communication.
However, instant messaging is on a smaller scale than a
chat room. Some instant messaging programs also
allow voice communication.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 41
With the appropriate hardware and software, it is possible
to make phone calls over the Internet. This is an
attractive option for long distance calls to avoid, or
reduce, charges. Videoconferencing allows both voice
and video image to be displayed in real-time for an
interactive meeting.
A codec is hardware used in both Internet phone and
videoconferencing applications. Codecs are used to
convert analog inputs, such as voice conversations or
videos, into digital signals for transmission over the
Internet.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 42
Table 7.5
Table 7.5 lists current phone service available over the
Internet. Use of voice over IP may increase as new uses
are found for sending voice, video and data concurrently.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 44
Internet Services
Content streaming: transfers multimedia
files continuously so users can view
them in real-time
Music, radio & video
3-D Internet sites
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 45
Content streaming is a method of transferring multimedia
files so that users can view them in real-time without
breaks or pauses. Large multimedia files, such as video
clips, have long download times and a user might need to
wait an hour before she could play the video on her
machine. Content streaming allows the video to be
viewed as it is being received.
Music is rapidly expanding on the Internet. MP3 is a
popular format for compressed music, allowing it to be
easily downloaded from the web, stored, and listened to.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 46
The ability to download music and movies from the
Internet has the music and video industry concerned
about copyright violations and reduced income. It is
clear that the Internet will have a big role in shaping the
music and video industries – exactly how will be seen in
the next few years.
Virtual reality types of applications are now on the web,
and likely to increase in the near future. For example, on
some sites, potential buyers can take a virtual tour of
homes. People can see and interact with products, such
as cars or computers, online.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 47
Internet Services
Shopping on the Web
Bots: web search tools
Web Auctions
Office on the web
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 48
More and more people and business are buying on the
Internet. Although the online retailers started having
trouble in late 2000 and many have, and will, fail or be
acquired, commerce over the Internet will increase.
Bots, short for “knowledge robots”, can help you find
what you want on the Internet or find the best prices.
Auction websites have become very popular on the
Internet. Internet auction sites, such as eBay, enable
individuals to post items they wish to sell and receive
offers, or bids from potential buyers.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 49
Some websites allow you to set up a virtual office for a
monthly fee. Companies and individuals do this to
provide contact lists, calendars, and file storage space to
employees, especially those who travel.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 50
The World Wide Web
The World Wide Web was originally developed as an
internal document management system. It has grown to
a huge, global collection of independent computers, or
web servers, and is the most famous Internet service.
Using hypertext links, or hypermedia, a type of crossindexing tool, users can jump from one web server to
another immediately. To the user, the entire web is like
one giant computer. You can jump from a page on one
web server to a page on a related topic that is stored on
the other side of the world. Hypertext links are
maintained using URLs.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 52
A URL is the logical address, such as www.course.com,
that you type in your browser when going to a website.
Web pages on web servers can contain data in any format
– from ASCII characters to video images.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 53
Fig 7.4
HTML, or hypertext markup language, is the standard
language used to create web pages. HTML “tags” tell
your browser how to format a particular text segment,
as well as what images, sound or other elements to
insert on the page. Tags are enclosed by an opening
“less than” arrow and an ending “greater than” arrow.
You can view the HTML code for a web page by
selecting “View” and “Source” from your browser’s
menu.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 55
Web Software
Web browsers
Search engines
Keyword indexes: fast & broad
 Subject indexes: focused searches

Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 56
Web browsers take make using the Internet easy by
handling all the work involved in connecting to the
various URLs you select. Netscape Navigator and
Microsoft’s Internet Explorer are the two most widely
used Web browsers.
There is so much information on the web that you need
help finding what you want. Search engines help you
find relevant web pages. Different search engines may
index different web pages, so if you don’t find what
you want with one search engine, you may with
another.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 57
Meta search engines are tools that submit your search to
multiple search engines for you. Usually, though, the
problem is the opposite – that your search finds thousand
of web pages matching your criteria. Keyword indexes
are search engines that don’t look at the content of the
pages they return, but just match the keywords you enter
to keywords on web pages. Although these are broad and
fast, you’ll most likely get a lot of irrelevant results.
Subject directories use humans and computers to analyze
the content of web pages and assign them to a category,
so searches are more focused, although subject directories
are not as comprehensive as keyword indexes.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 58
Table 7.7
Table 7.7 lists some of the popular search engines
available. You’ll find more as you surf the web.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 60
Figure 7.5
Java is an object-oriented programming language that
allows small programs – called applets – to be included in
HTML documents. Applets are small programs that are
downloaded to, and run on, the user’s computer, the client
computer. Java-enabled web pages can include animation
and real-time updates. Figure 7.5 shows how an applet
works. When the user accesses a web page, it is
downloaded to his computer. If the web page includes
HTML tags indicating a Java applet, if the tag is activated
by the users clicking on an area of an HTML web page to
execute the program, the client’s browser software checks
to see if the applet is already stored on the client.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 62
If not, it is downloaded from the web server and
executed on the client. Java applets can run on any
hardware and operating system platform.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 63
Webcasting
aka Push Technology
Consolidates information according to a
user’s profile & displays in the browser
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 64
Although users can search for sites on the Internet, push
technology can automatically provide customized
content to individuals. Webcasting, or push technology,
gathers information and brings it to the client computer.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 65
Developing Web Content
Tools
Word processors
 HTML editor
 HTML Template
 Text editor

View your page
Add effects judiciously
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 66
HTML standards are evolving, with new tags being
added frequently. Not all browsers, or even versions of
the same browser, work the same way when viewing a
web page, since each may be based on a different set of
standards.
You can create a web page in several ways. You can
create a document using word processing software, such
as Microsoft Word, and then convert the document to
HTML. Most word processors have an option to save a
document as a web page, making this an easy way to
create web pages.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 67
You can use web site development software, such as
Microsoft’ FrontPage or Macromedia’s DreamWeaver,
to create professional-looking websites without much
more difficulty than using a word processor. You can
also develop use an HTML editor, writing text and
adding tags, or using an ordinary text editor to write
text and type in tags. Additionally, there are many
existing HTML templates that simplify HTML
creation.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 68
After you create a webpage, always view it with a
browser. In fact, it is best to view your page in different
browsers and different versions of the same browser, to
ensure your page can be viewed by users who aren’t
using the latest version. Images, audio, animation or
video can be used to enhance the page or add content.
However, keep in mind that the more such effects you
have, the longer it will take to open the web page. When
finished, upload you web page to a web server. Typically,
file transfer protocol, or FTP, is used for this.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 69
Many ISPs give subscribers a small amount of space on a
web server. Additionally, there are free web hosting sites,
such as geocities and angelfire offer limited space for a
web site, although ads will appear on your web page.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 70
Intranets and Extranets
An intranet is an internal organizational network that
uses Internet and World Wide Web standards and
technologies. An intranet can be local or may connect all
of a corporation’s worldwide resources. These private
networks are used to provide employees or other internal
users information and to handle administrative tasks. For
example, in some firms employees can complete and file
forms such as travel reports over the intranet. Since so
many people are familiar with the Internet and World
Wide Web, they need little help in using intranets
effectively.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 72
Intranets are integrating computers, software and
databases that are dispersed throughout businesses
together – a feat that has eluded technologists and
managers until now.
An increasing number of organizations are offering
limited access to their intranet to specific customers or
suppliers. These networks, called extranets, connect
external people to those in the company, based on the
technologies of the Web.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 73
Table 7.8
Table 7.8 summarizes the difference between the Internet,
intranets and extranets.
Security and privacy concerns are even more critical for
an extranet than an intranet. In order to secure an intranet
or extranet, many organizations use a Virtual Private
Network, which is a secure network over the Internet.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 75
Fig 7.7
Figure 7.7 shows how a virtual private network operates.
In a virtual private network, messages are encoded when
the are sent across the virtual private network and
decoded upon receipt. Virtual private networks are often
available from Internet service providers.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 77
Net Issues
All types of networks – the Internet, intranets, extranets,
LANs and WANs - are all affected by control, access,
hardware and security issues. Since there is no central
governing body for the Internet, issues such as privacy or
offensive or sensitive material being placed on the
Internet are difficult to address. These issues are easier to
deal with for corporate networks.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 79
Net Issues
Service bottlenecks
Firewalls
Privacy & security
Cookies
 Cryptography
 Encryption
 Digital signature

Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 80
Most service bottlenecks on the Internet and corporate
intranets alike are caused by the rapid growth of usage.
When setting up a web server for internal or external
use, organizations often underestimate the volume and
frequency with which it will be accessed. Growth in
Internet traffic is also causing service problems. Internet
traffic is usually carried by multiple providers – some
have good service and some don’t. For instance, links to
Pacific Rim countries have been slow due to the limited
bandwidth. The routers connecting the many networks
of the Internet also slow traffic.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 81
Routers must consult a destination table for each packet
routed and can become overloaded. When packets are
lost, they must be retransmitted, which increases the
traffic on the Internet, further straining the routers.
Backbone providers and equipment manufacturers are
trying to improve Internet service by improving the
technology. Prioritization of traffic is also being
considered – customers could pay more for guaranteed
delivery speed.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 82
Firewalls are a combination of computer hardware and
software that connect internal networks to the Internet
and limit access to and from the organization’s network
based on a defined policy. Firewalls filter incoming traffic
and can be configured to limit access to certain
computers, certain networks, or certain types of traffic.
Inappropriate traffic is refused.
Before the Internet becomes a widespread way to do
business, individuals and business want to see security
and privacy issues adequately addressed.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 83
For instance, when you visit a website, a cookie may be
placed on your computer. Cookies are text files that
contain information about your usage of the website.
Cookies enable websites to customize the page you see,
not only with content based on your interests or your
pattern of using the website, but also by using your
name. However, companies can also use the information
cookies collect to assemble a detailed profile of you.
Most browsers allow you to reject cookies; however,
some websites don’t work correctly if you do.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 84
Cryptography involves encoding, or encrypting, a
message so that it can’t be read without the correct key,
and then decoding it with the key. The unencoded
message is called plaintext, and the encoded message is
called ciphertext. Good ciphertext appears to be a
random string of characters, so it is useless to anyone
intercepting it. Corporations are increasingly using
cryptography to ensure data security. Cryptography
requires specialized software. A digital signature is a
special encoding technique used to verify the sender’s
identity.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 85
Fig 7.8
The encryption and decoding processes are done by
software. Figure 7.8 shows how this process takes
place.
Chapter 7
Principles of Information Systems,
Fifth Edition
Slide 87