Transcript Intro to Information Systems

McGraw-Hill/Irwin
6-1
Copyright © 2007 by The McGraw-Hill Companies, Inc. All rights reserved.
Chapter
6
Telecommunications and
Networks
Business value of networks
The Internet
Network components
McGraw-Hill/Irwin
Copyright © 2007 by The McGraw-Hill Companies, Inc. All rights reserved.
Learning Objectives
Understand the concept of a network.
2. Apply Metcalfe’s law in understanding the value of
a network.
3. Identify several major developments and trends in
the industries, technologies, and business
applications of telecommunications and Internet
technologies.
4. Provide examples of the business value of Internet,
intranet, and extranet applications.
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Learning Objectives
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6.
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Identify the basic components, functions, and types
of telecommunications networks used in business.
Explain the functions of major components of
telecommunications network hardware, software,
media, and services.
Explain the concept of client/server networking.
Understand the two forms of peer-to-peer
networking.
Explain the difference between digital and analog
signals.
Learning Objectives
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Identify the various transmission media and
topologies used in telecommunications networks.
Understand the fundamentals of wireless network
technologies.
Explain the concepts behind TCP/IP.
Understand the seven layers of the OSI network
model.
Case 1: Wireless, Wireless Everywhere
 Wireless
sensor devices or motes
 Package
together a circuit board, software, sensors and
wireless radio
 Uses
mesh networking software to transmit data
from one mote to another
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Case Study Questions
What are some of the business benefits associated
with using wireless networks to collect and
transmit data?
2. What are some of the challenges being faced in this
use of wireless technologies? What solutions can
you offer?
3. The use of wireless networking as described in the
case is both innovative and useful. What other
business uses can you envision for this approach?
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Real World Internet Activity
1.
The companies mentioned in this case, Intel, IBM,
SAIC, and GE are all familiar names often
associated with innovative approaches to
technology. Using the Internet,
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See if you can find examples of other companies that
have found ways in which to apply mote wireless
technology to business needs.
Real World Group Activity
 One
way of describing this use of wireless
technologies is that it represents a marriage between
RFID and wireless networking. This combination of
enabling technologies results in an entirely new way
of accomplishing an old task. In small groups,
 Brainstorm
other combinations of existing technologies
to create new approaches to existing business activities.
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Network Concepts
 Network
 An
interconnected chain, group or system
 Number
(N-1)
 Where
of possible connections on a network is N *
N = number of nodes (points of connections on
the network)
 Example, if there are 10 computers on a network, there
are 10 * 9 = 90 possible connections
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Metcalfe’s Law
 The
usefulness of a network equals the square of the
number of users
 On a small network, a change in technology affects
technology only
 On a large network like the Internet, a change in
technology affects social, political and economic
systems
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Telecommunications
 Telecommunications
 Exchange
of information in any form (voice, data, text,
images, audio, video) over networks
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Trends in Telecommunications
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Open Systems
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Information systems that use common standards for hardware,
software, applications and networks
Internet networking technologies are a common standard for
open systems
Connectivity:
 Ability of networked computers to easily access and
communicate with each other and share information
Interoperability:
 The ability of an open system to enable end user applications
to be accomplished using different varieties of computer
systems, software packages, and databases provided by a
variety of interconnected networks
Middleware
 Any
programming that serves to “glue together” two
separate programs
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Digital Network Technologies
 Rapid
change from analog to digital network
technologies
 Analog: voice-oriented transmission, sound waves
 Digital: discrete pulse transmission
 Digital allows:
 Higher
transmission speed
 Larger amounts of information
 Greater economy
 Lower error rates
 Multiple forms of communications on same circuit
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Internet2
 Next
generation of the Internet
 High-performance network
 In use at 200 universities, scientific institutions,
communications corporations
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Business Value of
Telecommunication Networks
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The Internet
 Over
46 million servers (2004)
 710 – 945 million users (2004)
 No central computer system
 No governing body
 No one owns it
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Internet Service Provider
 ISP
A
company that specializes in providing easy access to
the Internet
 For a monthly fee, you get software, user name,
password and access
 ISPs
are connect to one another through network
access points
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Popular uses of the Internet
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Using the Internet for business
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Business value of the Internet
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An Intranet
A
network inside an organization
 That
uses Internet technologies (such as Web browsers
and servers, TCP/IP protocols, HTML, etc.)
 To provide an Internet-like environment within the
organization
 For information sharing, communications,
collaboration and support of business processes
 Protected by security measures
 Can be accessed by authorized users through the
Internet
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Enterprise Information Portal
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Extranet
 Network
 To
links that use Internet technologies
connect the Intranet of a business
 With the Intranets of its customers, suppliers or other
business partners
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Extranet Uses
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Case 2: Maryland and Colorado
Serving their customers without using wires
 Earth
Alert Emergency Management System in
Maryland provides
 Devices
to communicate warning to individuals before
a disaster, and
 Tools to collect timely information after a disaster
 Aurora
Colorado
 Connects
police and fire department vehicles via wireless connections
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Case Study Questions
What is the business value of advanced mobile
technologies to Maryland’s emergency
management services?
2. In what other government services could GPS serve
to provide business value? Give some examples.
3. Are there disadvantages or risks associated with
the deployment of GPS systems to monitor the
location of people? Explain.
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Real World Internet Activity
1.
The global positioning system (GPS) is a major
technological achievement that has broad-reaching
implications for business. Using the Internet,
See if you can find other innovative uses for GPS.
 Good places to start familiarizing yourself with
current accomplishments are
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The GPSWorld site at
http://www.gpsworld.com/gpsworld/
The GPS Overview at
http://www.colorado.edu/geography/gcraft/notes/gp
s/gps_f.html
Real World Group Activity
 The
first Real World Case in this chapter discussed
the combination of two existing technologies, RFID
and wireless networking, to create an innovative
business solution. In small groups,
 Brainstorm
innovative applications of GPS and other
existing technologies.
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Telecommunications network
 Any
arrangement where a sender transmits a
message to a receiver over a channel consisting of
some type of medium
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Telecommunications network
components
 Terminals:
any input/output device that uses
networks to transmit or receive data
 Telecommunications Processors: devices that support
data transmission and reception
 Telecommunications Channels: media over which
data are transmitted and received
 Computers: all sizes and types
 Telecommunications Control Software: programs
that control telecommunications activities
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Telecommunications network
model
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Wide Area Network (WAN)
 Telecommunications
geographic area
network that covers a large
Source: Courtesy of Cisco Systems Inc.
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Local Area Network (LAN)
 Connect
computers within a limited physical area
such as an office, classroom, or building
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Virtual Private Networks (VPN)
A
secure network that uses the Internet as its
backbone but relies on firewalls, encryption
and other security
 A pipe traveling through the Internet
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VPN
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Client/Server networks
 Clients:
End user personal computers or
networked computers
 Interconnected by LANs
 Servers: manage networks
 Processing shared between clients and
servers
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Client/Server Network
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Network Computing
 Networks
are the central computing resource of the
organization
 Thin clients: network computers and other clients
provide a browser-based user interface
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Peer-to-peer networks
 Networks
that connect from one PC to another PC
 Common use is the downloading and trading of files
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Peer-to-Peer Network
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Telecommunications Media
 Twisted-pair
wire:
 Ordinary telephone
wire
 Copper wire twisted
into pairs
Source: Phil Degginger/Getty Images.
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Telecommunications Media
 Coaxial
cable:
 Sturdy copper or
aluminum wire
wrapped with spacers
to insulate and
protect it
Source: Ryan McVay/Getty Images.
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Telecommunications Media
 Fiber-optic
cable:
 One or more hair-thin
filaments of glass
fiber wrapped in a
protective jacket
Source: CMCD/Getty Images.
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Problem of “The Last Mile”
 Network
providers use fiber optic to provide
backbone
 But houses are connected to the backbone via
twisted-pair
 Cannot get the benefit of the faster, better technology
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Wireless Technologies
 Terrestrial
microwave
 Earthbound
microwave systems that transmit highspeed radio signals in a line-of-sight path
 Between relay systems spaced approximately 30-miles
apart
 Communications
 Satellite serves
satellites
as relay stations for communications
signals
 Uses microwave radio signals
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Wireless Technologies
 Cellular
and PCS telephone and pager systems
 Divide
the geographic area into small areas or cells
 Each cell has transmitter or radio relay antenna to send
message from one cell to another
 Wireless
LANs
 Radio
signals within an office or building
 Connect PCs to networks
 Bluetooth
 Short-range
wireless technology
 To connect PC to peripherals such as printer
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Wireless Web
 Connect
Internet
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portable communications devices to the
Telecommunications Processors
 Modems
 Convert
digital signals from a computer into
 Analog frequencies that can be transmitted over
ordinary telephone lines
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Comparing modem and other
technologies
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Internetwork Processors
 Switch
– makes connections between
telecommunications circuits in a network
 Router – intelligent communications processor that
interconnects networks based on different protocols
 Hub – a port switching communications processor
 Gateway – connects networks using different
communications architectures
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Communications Processors
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Telecommunications Processors
 Multiplexer
 Allows
a single communications channel to carry
simultaneous data transmissions from many terminals
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Telecommunications Software
 Used by
servers and other computers to manage
network performance
 Network Operating Systems
 Middleware
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Network management functions
 Traffic
Management – manage network resources
and traffic to avoid congestion and optimize service
levels to users
 Security – provide authentication, encryption,
firewall, auditing and enforcement
 Network Monitoring – troubleshoot and watch over
the network, informing network administrators of
potential problems before they occur
 Capacity Planning – survey network resources and
traffic patterns and users’ needs to determine how
best to accommodate the needs of the network as it
grows and changes
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Network Topologies
 Topology:
 Star:
structure of a network
ties end user computers to a central computer
 Ring: ties local computer processors together in a
ring on a relatively equal basis
 Bus: local processors share the same communications
channel
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Network Topologies
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Network Architectures &
Protocols
 Protocol:
standard set of rules and procedures for the
control of communications in a network
 Network Architecture:
 Master
plan of standard protocols, hardware, software
and interfaces between end users and computer
systems
 Goal of promoting an open, simple, flexible, and
efficient telecommunications environment
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OSI & TCP/IP Models
 Open
Systems Interconnection (OSI) Model
A
seven-layer model that serves as a standard model
for network architectures
 Model for how messages should be transmitted
between two points in a network
 Each layer adds functions
 Transmission
(TCP/IP)
A
Control Protocol / Internet Protocol
five layer telecommunications protocol used by the
Internet
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OSI & TCP/IP Models
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Internet Telephony
 Using
an Internet connection to pass voice data using
IP
 Voice over IP (VoIP)
 Skips standard long-distance phone charges
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Bandwidth
 Bandwidth
 Frequency
range of a telecommunications channel
 Determines transmission rate
 Classified in bits per second (bps)
 Transmission
Rates:
 Narrow-band
– low-speed
 Broadband – high-speed
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Transmission Speeds
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Switching Alternatives
 Circuit
Switching
 Switch
opens a circuit to establish a link between a
sender and receiver
 it remains open until the communication session is
completed
 Packet
Switching
 Break
messages into groups called packets
 Transmit packets separately
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Network Interoperability
 Ensure
that anyone anywhere on one network
 Can communicate
 With anyone anywhere on another network
 Telecommunications
as discussed in this chapter
wouldn’t be possible without interoperability
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Case 3: Voice Over IP is the Real
Thing
 VoIP
works by
 Digitizing
a voice signal,
 Chopping it into packets, and
 Sending them over a company’s network or the
Internet
 Packets are reassembled at the destination
 Minnesota
Department of Labor has cut its monthly
phone bill in half
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Case Study Questions
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What are the main benefits that can be gained by
companies that switch to VoIP systems?
What are some of the major cost factors that may
limit a positive rate of return from investments in
VoIP projects?
Should more companies switch to VoIP systems?
Visit the websites of Avaya and Cisco Systems to
view their VoIP news, products, and services to
help you answer.
Real World Internet Activity
1.
VoIP is becoming a highly competitive marketplace
for the delivery of services and the development of
software to support the process. Using the Internet,
See if you can identify who the major players are in
this market.
 Where do you see the next significant development
for VoIP?
 Do you think the concept will eventually replace
conventional telephone technologies? Why or why
not?
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Real World Group Activity
 The
original concept for the Internet never included
many of the uses we have found for it and consider
commonplace today. While Internet2 is on the
horizon, we need to think about what uses we may
want from the Internet in the future. In small groups,
 Brainstorm
how we might use the Internet in the
future.
 Do we run the risk of overloading the Internet or
relying on it too much?
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