Transcript communications and networks

9
COMMUNICATIONS
AND NETWORKS
McGraw-Hill Technology Education
© 2006 by the McGraw-Hill Companies, Inc. All rights reserved.
Competencies (Page 1 of 2)
Discuss connectivity, the
wireless revolution, and
communication systems
Describe physical and wireless
communications channels
Discuss connection devices,
including modems, T1, DSL,
cable modem, and satellite
connections
Describe data transmission
factors, including bandwidths
and protocols
Discuss network and key
network terminology
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Competencies (Page 2 of 2)
Describe different types of
networks, including local area,
metropolitan area, and wide
area networks
Describe network
architectures, including
configurations and strategies
Describe organizational uses of
Internet technologies,
including intranets, extranets,
and firewalls
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Communications
The process of sharing data, programs, and
information between two or more computers
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Communications Today
Numerous applications depend on communication
systems—E-mail, Instant messaging (IM), Internet
telephone, and Electronic commerce
Connectivity uses computer networks to link people
and resources
Going wireless has been the most dramatic change
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Communication Systems
Four basic elements
Sending and receiving devices
Communication channel
Connection devices
Data transmission specifications
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Communication Channels
Channels carry data from one computer to
another
Two categories of communication channels
Physical connection
Wireless connection
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Connection Device Signals
Types of signals
Analog
Digital
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Connection Device Types
Types of modems
External
Internal
PC Card
Wireless
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Connection Services
Dial-Up services
Leased lines – T1, T2, T3 and T4
Digital subscriber line (DSL)
Uses existing phone lines
One type widely used is ADSL
Cable modems
Uses existing TV cable
Provides speeds as fast as DSL at a lower cost
Satellite/air connection services
Seven times faster than dial-up
Slower than DSL & cable modem
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Typical User Connection Costs & Speeds
Type
Fee
Speed
Seconds to Get
Images
Dial-up
$16
56 kbps
45.0
DSL
50
1.5 mbps
1.7
Cable Modem
40
1.5 mbps
1.7
Satellite
60
900 kbps
2.8
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Bandwidth
Measurement of the capacity of the channel
Categories
Low bandwidths or Voiceband
Medium band
Broadband
Used for high capacity transmission
Used by DSL, cable, and satellite
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Protocols
Set of communication rules
Standard for Internet: TCP/IP (Transmission
control protocol/Internet protocol)
Identifies devices
Reformats information
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Networks
A computer network is a communication
system
Connects two or more computers
Allows information exchange
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Network Terms
Computer Networks Connect Computers
Node
Client
Server
Hub
Network interface cards (NIC)
Network operating system
(NOS)
Distributed processing
Host computer
Network manager
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Network Types
Local area networks
Home networks
WLAN
Metropolitan
area networks
Wide area networks
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Network Architecture
Architecture describes how a network is
arranged
Arrangement is called topology
Types of network topology
Star
Bus
Ring
Hierarchical
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Strategies
Strategy is a way of
coordinating the
sharing of information
and resources
Common network
strategies
Terminal
Client/server
Peer-to-peer
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Internets and Extranets
Intranets
Private network within an
organization
Provides information to employees
Extranets
Private network that connects
organizations
Used to allow suppliers and others
access
Firewalls
Security system
Protects against external threats
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A Look to the Future
Wireless Robotic Car
Pod car (Personalization on Demand)
Predicts and responds
Designed to learn and adapt to an individual's
driving needs and habits
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Discussion Questions
Define and discuss connectivity, the wireless
revolution, and communications.
Identify and describe the various physical and
wireless communication channels.
Identify the standard Internet protocol and
discuss its essential features.
Define and discuss the four principal network
topologies.
Define and discuss the three most common
network strategies.
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