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Working Outside
the Box
Basic Concepts
•
•
•
•
Telecommunications Basics 
The Internet, a network of networks 
The World-wide-web, an Internet implementation 
Serious Issues 

MIS 300, Chapter 4
2
Principles and Learning Objectives -1
• Effective communications are essential to
organizational success. 
– Define the term telecommunications and describe the
function of the components of a telecommunications
system.
– Identify the three types of telecommunications
carriers and discuss the services they provide.
– Name three distributed processing alternatives and
outline their basic features.
MIS 300, Chapter 4
3
Principles and Learning Objectives -2
• The Internet is like many other technologies—it
provides a wide range of services, some of which
are effective and practical for use today, others are
still evolving, and still others will fade away from lack
of use. 
– Briefly describe how the Internet works, including
alternatives for connecting to it and the role of Internet
service providers.
MIS 300, Chapter 4
4
Principles and Learning Objectives -3
• Originally developed as a document-management
system, the World Wide Web is a menu-based
system that is easy to use for personal and business
applications. 
– Describe the World Wide Web and the way it works,
including the use of Web browsers, search engines,
and other Web tools.
MIS 300, Chapter 4
5
Principles and Learning Objectives -4
• Because the Internet and the World Wide Web are
becoming more universally used and accepted for
business, management, service, and speed, privacy
and security issues must continually be addressed
and resolved. 
– Identify and briefly describe the applications
associated with the Internet and the Web.
– Define the terms intranet and extranet and discuss
how organizations are using them.
– Identify several issues associated with the use of
networks.
MIS 300, Chapter 4
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An Overview of Telecommunications
and Networks
• Telecommunications: the electronic transmission
of signals for communications
• Telecommunications medium: anything that
carries an electronic signal and interfaces between a
sending device and a receiving device
• Telecommunications carrier: any business that
provides (leases, services) telecommunications
media.
• Telecommunications service: any service to
customers at least partially facilitated by
telecommunications
MIS 300, Chapter 4
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Communication Model
Expression
Meaning1
Sender
Encoding
Interpretation
Channel
Decoding
Meaning2
Receiver
Challenges:
1. Various processes
2. Will meanings match?
3. Why encode?
4. Purpose? Intention?
MIS 300, Chapter 4
M e s s ag e
8
Characteristics of Communication
•
•
•
•
•
•
•
Encoding/decoding scheme
Speed of transmission (baud)
Directionality (one-way, bidirectional, switchable)
Noise
Equivocation (loss of signal)
Ambiguity (loss of meaning)
Turntaking (protocol)
MIS 300, Chapter 4
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The Telecommunications Problem
Sender
Encoding
Channel
Decoding
Receiver
Distance: Sender and Receiver are not in direct contact
Equivocation: Message loses power over distance
Noise: Channel introduces unwanted message
Coordination: It’s not clear what a message event is
MIS 300, Chapter 4
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Solutions to the problems
Sender
Encoding
Channel
Decoding
Receiver
Distance: Long “wires” of various types
Equivocation: Boosting of power (introduces noise)
Noise: Special encoding schemes
Coordination: Coordination messages (protocols)
Notice: Nothing about meaning, intention
MIS 300, Chapter 4
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Basic Economics
•
•
•
•
Sources aren’t “on” all the time
Sources make mistakes; repetition is dangerous and costly
Channels are usually relatively expensive
Sharing channels is a good use of an expensive resource;
sharing is costly
• All channels are error-prone; the way to compensate is
redundancy
• The more complex the scheme, the higher the cost and the
more likely is failure or error.
MIS 300, Chapter 4
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What Is a Signal?
ANALOG
signal: strength
is proportional to
“content”
• A communication event
• Has a definite start and stop
• Carries information (which is NOT the signal)
DIGITAL signal:
strength is fixed
at either 0 or a
constant
1
0
MIS 300, Chapter 4
1
1
1
0
1
0
0
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Inside a Digital Signal
The bits that form part of the byte
may be ones (at or above a certain
level) or zero (below this level). This
byte is 1011 0110 (1’s in color)
Ending of byte has
special “bit” called a
bit4
MIS 300,stop
Chapter
Beginning of byte
has special “bit”
called a start bit
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What Is the Advantage of Digital Signalling?
• First, simplicity, only two signal levels
• Second, resistance to noise
• Third, amplification can work without amplifying
noise
• Fourth, potential to add check bits to reconstruct
byte in the event of errors (for example, parity
checking).
MIS 300, Chapter 4
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“On” threashold
Amplification
Original 0-1
Signal is “clipped”
at threashold level
MIS 300, Chapter 4
Over
distance,
signal
weakens
…and then
amplified
Noise
intrudes
…and sent on its way again
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The Equipment is Connected
This is only
what you see!
Figure 4.1: Elements of a (Physical) Telecommunications
System
MIS 300, Chapter 4
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Transmission Media -1
Table 4.1: Telecommunications Transmission Media Types
MIS 300, Chapter 4
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Transmission Media - 2
Table 4.1: Telecommunications Transmission Media Types
MIS 300, Chapter 4
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Telecommunications Devices
Table 4.2: Common Telecommunications Devices
MIS 300, Chapter 4
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Carriers and Services
• Local exchange carrier (LEC): a public telephone
company in the United States that provides service
to homes and businesses within its defined
geographical area
• Competitive local exchange carrier (CLEC): a
company that is allowed to compete with the LECs,
such as a wireless, satellite, or cable service
provider
• Long-distance carrier: a traditional long-distance
phone provider, such as AT&T, Sprint, or MCI
MIS 300, Chapter 4
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Carriers and Services (continued)
Figure 4.3: Local Exchange Carriers
MIS 300, Chapter 4
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Networks
• Computer network: the communications media,
devices, and software needed to connect two or
more computer systems or devices
• Network nodes: the computers and devices on
the networks
Node
MIS 300, Chapter 4
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What Are Networks For?
• At an electrical level, networks move electrons along paths
between nodes
• At a signal level, networks move coded characters along
links connecting nodes
• At a transportation level, networks move packages or packets
of characters between source and destination along paths
within the network
• At a session level, networks move messages from sender to
receiver.
• At the application level, networks move information from a
server to a client.
Businesses can select various ways for this to happen.
MIS 300, Chapter 4
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Basic Processing Strategies
• Centralized processing: all processing occurs in a
single location or facility
• Decentralized processing: processing devices are
placed at various remote locations
• Distributed processing: computers are placed at
remote locations but connected to each other via a
network
MIS 300, Chapter 4
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Terminal-to-Host, File Server, and
Client/Server Systems
• Connecting computers in distributed information
processing:
– Terminal-to-host: the application and database
reside on one host computer, and the user interacts
with the application and data using a “dumb” terminal
– File server: the application and database reside on
the one host computer, called the file server
– Client/server: multiple computer platforms are
dedicated to special functions, such as database
management, printing, communications, and program
execution
MIS 300, Chapter 4
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Terminal-to-Host, File Server, and
Client/Server Systems -2
Figure 4.6: Client/Server Connection
MIS 300, Chapter 4
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Network Types
•
•
•
•
•
•
Personal area network (PAN)
Local area network (LAN)
Metropolitan area network (MAN)
Wide area network (WAN)
International network
Corrupt local area network (CLAN) 
MIS 300, Chapter 4
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Network Types -2
Figure 4.7: A Typical LAN
MIS 300, Chapter 4
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Network Types - 3
Figure 4.8: A Wide Area Network
MIS 300, Chapter 4
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Communications Software and
Protocols
• Communications software: software that provides
a number of important functions in a network, such
as error checking and data security
• Network operating system (NOS)
• Network management software
• Communications protocol: a standard set of rules
that controls a telecommunications connection
MIS 300, Chapter 4
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Packet Switching
• Sender’s message is broken into (generally short,
fixed-length) packets
• Each packet is numbered and sent “into” the
network
• The network transmits the packets
• The node assembles the packets in order (not an
easy task)
• The receiver gets the message from the node.
MIS 300, Chapter 4
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Example of Packet Switching
456
Message
FROM: Node 223
TO: Node 456
P3
Count: 4
This is packet 1
This is packet 2
This is packet 3
P2
P4
223
P4
P3
P2
P1
P1
Packet reassembly
Transmission: each
packet has its own path
through the network
This is packet 4
Costs
Packet creation
MIS 300, Chapter 4
Benefits
Packet creation Better use of network
Packet handling Smaller units
Chance of error More even use of n/w
Retransmissions Higher traffic
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Use and Functioning of the Internet
• Internet: a collection of interconnected networks, all
freely exchanging information
• ARPANET
– The ancestor of the Internet
– A project started by the U.S. Department of Defense
(DoD) in 1969
• Internet Protocol (IP): communication standard
that enables traffic to be routed from one network to
another as needed
MIS 300, Chapter 4
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How the Internet Works
• The Internet transmits data from one computer
(called a host) to another
• If the receiving computer is on a network to which
the first computer is directly connected, it can send
the message directly
• If the receiving computer is not on a network to
which the sending computer is connected, the
sending computer relays the message to another
computer that can forward it
MIS 300, Chapter 4
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How the Internet Works (continued)
Figure 4.9: Routing Messages over the Internet
MIS 300, Chapter 4
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How the Internet Works (continued)
• Data is passed in chunks called packets
• Internet Protocol (IP): communications standard
that enables traffic to be routed from one network to
another as needed
• Transmission Control Protocol (TCP): widely
used transport-layer protocol that is used in
combination with IP by most Internet applications
• Uniform Resource Locator (URL): an assigned
address on the Internet for each computer
MIS 300, Chapter 4
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Accessing the Internet
• Connect via a LAN server
• Connect via Serial Line Internet Protocol
(SLIP)/Point-to-Point Protocol (PPP)
• Connect via an online service
• Other ways to connect
MIS 300, Chapter 4
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Accessing the Internet (continued)
Figure 4.10: Several Ways to Access the Internet
MIS 300, Chapter 4
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Internet Service Providers
• Internet service provider (ISP): any company that
provides individuals or organizations with access to
the Internet
• Most charge a monthly fee
• Many ISPs and online services offer broadband
Internet access through digital subscriber lines
(DSLs), cable, or satellite transmission

MIS 300, Chapter 4
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The World Wide Web
• The Web, WWW or W3
• A menu-based system that uses the client/server
model
• Organizes Internet resources throughout the world
into a series of menu pages, or screens, that appear
on your computer
• Hypermedia: tools that connect the data on Web
pages, allowing users to access topics in whatever
order they want
MIS 300, Chapter 4
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The World Wide Web (continued)
• Hypertext Markup Language (HTML): the
standard page description language for Web pages
• HTML tags: codes that let the browser know how to
format the text on a Web page and whether images,
sound, and other elements should be inserted
MIS 300, Chapter 4
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The World Wide Web (continued)
Figure 4.11: Sample Hypertext Markup Language
MIS 300, Chapter 4
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Web Browsers
• Web browser: software that creates a unique,
hypermedia-based menu on a computer screen,
providing a graphical interface to the Web
• The menu consists of graphics, titles, and text with
hypertext links
• Ubiquitous and non-proprietary web browsers make
it possible for the Internet to be a business platform.
MIS 300, Chapter 4
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Search Engines
•
•
•
•
Search engine: a Web search tool
Examples: Yahoo.com, Google.com
Most search engines are free
Searches can use words, such as AND and OR, to
refine the search
MIS 300, Chapter 4
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Web Programming Languages
• Java
– An object-oriented programming language from Sun
Microsystems based on C++
– Allows small programs (applets) to be embedded
within an HTML document
MIS 300, Chapter 4
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Web Services
• Standards and tools that streamline and simplify
communication among Web sites for business and
personal purposes
• Can also be used to develop new systems to send
and receive secure messages between healthcare
facilities, doctors, and patients, while maintaining
patient privacy
MIS 300, Chapter 4
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Internet and Telecommunications
Services
• E-mail and instant messaging
– Instant messaging: a method that allows two or
more individuals to communicate online, using the
Internet
• Internet cell phones and handheld computers
• Career information and job searching
• Web log (blog): a Web site that people can create
and use to write about their observations,
experiences, and feelings on a wide range of topics
MIS 300, Chapter 4
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Internet and Telecommunications
Services (continued)
• Chat rooms: enable two or more people to engage
in interactive “conversations” over the Internet
• Internet phone and videoconferencing services
• Content streaming: a method for transferring
multimedia files over the Internet so that the data
stream of voice and pictures plays more or less
continuously without a break, or very few of them
• Shopping on the Web
MIS 300, Chapter 4
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Internet and Telecommunications
Services (continued)
• Web auctions
• Music, radio, and video on the Internet
• Other Internet services and applications
MIS 300, Chapter 4
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Intranets and Extranets
• Intranet
– Internal corporate network built using Internet and
World Wide Web standards and products
– Used by employees to gain access to corporate
information
– Slashes the need for paper
MIS 300, Chapter 4
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Intranets and Extranets (continued)
• Extranet
– A network based on Web technologies that links
selected resources of a company’s intranet with its
customers, suppliers, or other business partners
• Virtual private network (VPN): a secure
connection between two points across the Internet
• Tunneling: the process by which VPNs transfer
information by encapsulating traffic in IP packets
over the Internet
MIS 300, Chapter 4
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Intranets and Extranets (continued)
Figure 4.12: Virtual Private Network

MIS 300, Chapter 4
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Net Issues
• Management issues
– No centralized governing body controls the
Internet
• Service and speed issues
– Web server computers can be overwhelmed by
the amount of “hits” (requests for pages)
– More and more Web sites have video, audio clips,
or other features that require faster Internet
speeds
MIS 300, Chapter 4
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Net Issues (continued)
• Privacy
– Spyware: hidden files and information trackers that
install themselves secretly when you visit some
Internet sites
– Cookie: a text file that an Internet company can place
on the hard disk of a computer system
• Fraud
– Phishing
MIS 300, Chapter 4
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Net Issues (continued)
• Security with encryption and firewalls
– Cryptography: converting a message into a secret
code and changing the encoded message back to
regular text
– Digital signature: encryption technique used to verify
the identity of a message sender for processing
online financial transactions
– Firewall: a device that sits between an internal
network and the Internet, limiting access into and out
of a network based on access policies
MIS 300, Chapter 4
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Net Issues (continued)
Figure 4.13: Cryptography is the process of converting a
message into a secret code and changing the encoded
message back into regular text. 
MIS 300, Chapter 4
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Summary
• Telecommunications is the electronic transmission of
signals for communications
• A computer network consists of the communications
media, devices, and software needed to connect
two or more computer systems or devices
• Ways of connecting computers in distributed
information processing: terminal-to-host, file server,
and client/server
MIS 300, Chapter 4
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Summary (continued)
• Network types: personal area network (PAN), local
area network (LAN), metropolitan area network
(MAN), wide area network (WAN), and international
network
• The Internet is a collection of interconnected
networks, all freely exchanging information
• Internet Protocol (IP) is a communication standard
that enables traffic to be routed from one network to
another as needed
MIS 300, Chapter 4
59
Summary (continued)
• Uniform Resource Locator (URL) is an assigned
address on the Internet for each computer
• An intranet is an internal corporate network built
using Internet and World Wide Web standards and
protocols
• An extranet is a network based on Web
technologies that links selected resources of a
company’s intranet with its customers, suppliers, or
other business partners
MIS 300, Chapter 4
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