Transcript ภาพนิ่ง 1

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Telecommunications
and
Networks
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Learning Objectives
• Identify major developments and
trends in the industries,
technologies, and business
applications of telecommunications
and Internet technologies.
• Provide examples of the business
value of Internet, intranet, and
extranet applications.
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4 Learning Objectives (continued)
• Identify the basic components,
functions, and types of
telecommunications networks used
in business.
• Explain the functions of major types
of telecommunications network
hardware, software, media, and
services.
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Section I
• The Networked Enterprise
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Networking the Enterprise
• Networking business and
employees
• Connecting them to customers,
suppliers, and other stakeholders.
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Trends in Telecommunications
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Trends in Telecommunications (continued)
– Industry
• More competitive
• More options for the firm
– Technology
• Unrestricted connectivity
• Easy access for end users
– Open systems
» Use common standards for hardware,
software, applications, & networking.
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Trends in Telecommunications (continued)
– Technology (continued)
• High degree of interoperability
• Digital networks
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Higher transmission speeds
Moves larger amounts of information
Greater economy
Lower error rates
Multiple types of communications on the same
circuits
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Trends in Telecommunications (continued)
– Technology (continued)
– Fiber-optic lines & cellular, PCS, satellite &
other wireless technologies
» Faster transmission speeds
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Trends in Telecommunications (continued)
– Business applications
• Dramatic increase in the number of
feasible telecommunication applications.
• Cut costs, reduce lead times, shorten
response times, support e-commerce,
improve collaboration, share resources,
lock in customers & suppliers, & develop
new products & services
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Business Value of Telecommunications
Networks
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The Internet
• A network of networks
• Popular uses
– E-mail
– Instant messaging
– Browsing the World Wide Web
– Newsgroups and chat rooms
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The Internet (continued)
• The business value of the Internet
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Intranets
• Within an organization
• Uses Internet technologies
• Business value of Intranets
– Used for information sharing,
communication, collaboration, &
support of business processes.
– Web publishing
• Comparatively easy, attractive, & lower
cost alternative for publishing & accessing
multimedia business information
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Intranets (continued)
– Business Operations & Management
• Used for developing & deploying critical
business applications
• Supports operations and managerial
decision making
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Extranets
• Network links that use Internet
technologies to interconnect the
firm’s intranet with the intranets of
customers, suppliers, or other
business partners
– Consultants, subcontractors, business
prospects, & others
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Extranets (continued)
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• Business value
– Improve communication with
customers and business partners
– Gain competitive advantage in
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Product development
Cost savings
Marketing
Distribution
Leveraging their partnerships
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Section II
• Telecommunications Network
Alternatives
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Telecommunications Network Alternatives
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A Telecommunications Network Model
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A Telecommunications Network Model
(continued)
• Consists of five basic components
– Terminals
• Any input/output device that uses
telecommunication networks to transmit or
receive data
– Telecommunication processors
• Support data transmission and reception
between terminals and computers
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A Telecommunications Network Model
(continued)
• Telecommunications channels
– The medium over which data are transmitted
and received
• Computers
– Interconnected by telecommunications
networks
• Telecommunications control software
– Control telecommunications activities &
manage the functions of telecommunications
networks
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Types of Telecommunications Networks
• Wide Area Networks (WAN)
– Cover a large geographic area.
• Local Area Networks (LAN)
– Connect computers & other information
processing devices within a limited
physical area.
– Connected via ordinary telephone
wiring, coaxial cable, or wireless radio
& infrared systems
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Types of Telecommunications Networks
(continued)
• Virtual Private Networks
– A secure network that uses the
Internet as its main backbone network,
but relies on fire walls and other
security features
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Types of Telecommunications Networks
(continued)
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Types of Telecommunications Networks
(continued)
• Client/Server Networks
– Clients – end user PCs or NCs
– Server – helps with application
processing and also manages the
network
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Types of Telecommunications Networks
(continued)
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Types of Telecommunications Networks
(continued)
• Network computing
– “the network is the computer”
• Thin clients process small application
programs called “applets.”
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Types of Telecommunications Networks
(continued)
• Peer-to-Peer (P2P)
– Two major models
• Central server architecture
• Pure peer-to-peer
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Telecommunications Media
• Twisted-pair wire
• Coaxial cable
– Minimizes interference and distortion
– Allows high-speed data transmission
• Fiber optics
– Glass fiber that conducts pulses of light
generated by lasers
– Size and weight reduction
– Increased speed and carrying capacity
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Telecommunications Media (continued)
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Wireless Technologies
• Terrestrial Microwave
– Line-of-sight path between relay stations
spaced approximately 30 miles apart.
• Communications Satellites
– Geosynchronous orbits
– Serve as relay stations for communications
signals transmitted from earth stations
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4 Wireless Technologies (continued)
• Cellular & PCS Systems
– Each cell is typically from one to
several square miles in area.
– Each cell has its own low-power
transmitter or radio relay antenna.
– Computers & other communications
processors coordinate & control the
transmissions to/from mobile users as
they move from one cell to another
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4 Wireless Technologies (continued)
• Wireless LANs
– Spread spectrum
– Wi-Fi (wireless fidelity)
• Wireless Web
– Uses Web-enabled information
appliances
– Very thin clients
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4 Telecommunications Processors
• Modems
(modulation/demodulation)
– Changes signals from analog to digital
and back to analog
• Multiplexers
– Allows a single communication
channel to carry simultaneous data
transmissions from many terminals
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Telecommunications Processors (continued)
• Internetwork Processors
– Switches
• Makes connections between telecomm
circuits so a message can reach its
intended destination
– Router
• Interconnects networks based on different
rules or protocols
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Telecommunications Processors (continued)
– Hub
• Port switching communications processor
– Gateway
• A processor that interconnects networks that
use different communications architecture
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Telecommunications Software
• Provides a variety of
communications support services
including connecting &
disconnecting communications links
& establishing communications
parameters such as transmission
speed, mode, and direction.
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Telecommunications Software (continued)
• Network Management
– Traffic management
– Security
– Network monitoring
– Capacity planning
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Network Topologies
• Star
– Ties end user computers to a central
computer
– Considered the least reliable
• Ring (sometimes called Token Ring)
– Ties local computer processors together in a
ring on a more equal basis.
– Considered more reliable & less costly
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4 Network Topologies (continued)
• Bus
– Local processors share the same
bus, or communications channel
– Tree is a variation which ties several
bus networks together
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4 Network Topologies (continued)
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4 Network Architectures & Protocols
• Protocols
– A standard set of rules & procedures for the
control of communications in a network
– Standards for the physical characteristics of
cables and connectors
• Network Architecture
– Goal is to promote an open, simple, flexible,
efficient telecommunications environment
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Network Architectures and Protocols
(continued)
• OSI Model
• TCP/IP
– Transmission Control
Protocol/Internet Protocol
• Used by the Internet and all intranets and
extranets
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Bandwidth Alternatives
• Bandwidth is the frequency range of a
telecommunications network
• Determines the channel’s maximum
transmission rate
• Measured in bits per second (bps) or
baud
• Narrow-band
– Low-speed transmission
• Broadband
– High-speed transmission
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Switching Alternatives
• Circuit switching
• Packet switching
• Cell switching
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Discussion Questions
• The Internet is the driving force behind
developments in telecommunications,
networks, and other information
technologies. Do you agree or disagree?
• How is the trend toward open systems,
connectivity, and interoperability related to
business use of the Internet, intranets,
and extranets?
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4 Discussion Questions (continued)
• How will wireless information appliances
and services affect the business use of
the Internet and the Web?
• What are some of the business benefits
and management challenges of
client/server networks? Network
computing? Peer-to-peer networks?
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4 Discussion Questions (continued)
• What is the business value driving
so many companies to rapidly install
and extend intranets throughout
their organizations?
• What strategic competitive benefits
do you see in a company’s use of
extranets?
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4 Discussion Questions (continued)
• Do you think that business use of the
Internet, intranets, and extranets has
changed what businesspeople expect
from information technology in their jobs?
• Do you believe that the insatiable
demand for everything wireless, video,
and Web-enabled will be the driving force
behind developments in
telecommunications, networking, and
computing technologies for the
foreseeable future?
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References
• James A. O'Brien; George M. Marakas.
Management Information Systems:
Managing Information Technology in the
Business Enterprise 6th Ed., Boston:
McGraw-Hill/ Irwin,2004
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