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Computers
© 2005 Prentice-Hall, Inc.
Slide 1
Computers
Chapter 6
Networks and Networking
© 2005 Prentice-Hall, Inc.
Slide 2
Computers
Chapter 6 – Networks and Networking
Objectives
 Apply the concept of connectivity to your life
 Understand data communications hardware
 Identify data transmissions services
Understand the various network topologies
Recognize the potential of home networking
© 2005 Prentice-Hall, Inc.
Slide 3
Computers
Networks and Networking
Our Wired World
 Connectivity – the degree to which
software, hardware, and databases are
functionally linked
© 2005 Prentice-Hall, Inc.
Slide 4
Computers
Networks and Networking
Our Wired World
 Cooperative processing
 Intracompany networking – cooperation
within the company
 Intercompany networking – cooperation
with other companies and customers
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Slide 5
Computers
Networks and Networking
Our Wired World
 Intranet –internal network based on
Internet technology
 Extranet – an extension of an
intranet, partially available to
authorized customers and suppliers
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Slide 6
Computers
Networks and Networking
Our Wired World
 Virtual Private Network (VPN) –
network transmissions are tunneled
through the Internet
 Tunneling – one network uses
another to send data
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Slide 7
Computers
Networks and Networking
Data Communications Hardware
Data communications or
telecommunications – distribution of
data
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Slide 8
Computers
Networks and Networking
Data Communications Hardware
 Server computers – central computers
that control the network
 Client computers – computers, linked
to a server, that create the network
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Computers
Networks and Networking
Data Communications Hardware
 Proxy server computers – handle
some requests, hand others to the actual
server computers
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Slide 10
Computers
Networks and Networking
Data Communications Hardware
 Telephone-link modem – converts
analog signals to digital and digital
signals to analog
 Analog – voice communication, such
as over a telephone line
Digital – 1’s and 0’s used to represent
data in a computer
© 2005 Prentice-Hall, Inc.
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Computers
Networks and Networking
Data Communications Hardware
 Modem
Internal
External
Voice/data/fax modem
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Computers
Networks and Networking
Data Communications Hardware
 Cable modem – provides Internet
access via cable television lines
 DSL (Digital Subscriber Line) –
Internet access via special line provided
by a telephone company
 Satellite modem – Internet access via
communications satellite
© 2005 Prentice-Hall, Inc.
Slide 13
Computers
Networks and Networking
Data Communications Hardware
 Network interface card (NIC) – also
called network card and network
adapter
Needed to connect a personal computer
to a network
Ethernet – de facto standard
© 2005 Prentice-Hall, Inc.
Slide 14
Computers
Networks and Networking
Data Communications Hardware
 Gateway – allows for communication
between networks using different
protocols
 Router – routes messages to the
appropriate destination
Gateway router – both functions in
one device
© 2005 Prentice-Hall, Inc.
Slide 15
Computers
Networks and Networking
Data Communications Hardware
 Message
Source – device that sends the message
Destination – device that receives the
message
Handshaking – router establishes the
connection between the source and the
destination
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Slide 16
Computers
Networks and Networking
Data Communications Hardware
 Network address – assigned to each
computer on a network; used to send
messages to the appropriate destination
 Backbone – the routers, gateways,
and other equipment that link the
computers of the network
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Slide 17
Computers
Networks and Networking
Data Communications Hardware
 Hub – expands the number of nodes
on a network
Half-duplex – data can only be sent in
one direction at a time
 Switch – acts like a hub for a local
area network (LAN)
Full-duplex – data can be sent in both
directions at once
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Slide 18
Computers
Networks and Networking
Data Communications Hardware
 Terminals
Video Display Terminal (VDT) –
input/output device
Thin client – smart terminal, capable of
some processing
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Computers
Networks and Networking
Data Communications Hardware
 Telephony – integration of telephones
and computers
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Computers
Networks and Networking
Data Communications Hardware
Automatic Teller Machine (ATM) –
used in banking
 Point-of-Sale (POS) terminals – used
in retail
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Computers
Networks and Networking
The Data Communications Channel
Communications channel – media a
message must pass through on a
network
Line
Link
Pipe
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Computers
Networks and Networking
The Data Communications Channel
Transmission media
Measured in bits per second (bps)
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Computers
Networks and Networking
The Data Communications Channel
Twisted-pair wire
POTS (plain old telephone services)
Digital Subscriber Line (DSL)
Cat5 cabling – uses four twisted pairs
of wire; speeds of up to 100 Mbps
Cat5e cabling – speeds of up to 1
Gbps
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Slide 24
Computers
Networks and Networking
The Data Communications Channel
Coaxial cable – high capacity channel,
capable of speeds up to 10 M bps
Fiber optic cable – carries data as
laser generated pulses of light
© 2005 Prentice-Hall, Inc.
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