chapter copyright 2003 the mcgraw-hill companies, inc.copyright 2003 the mcgraw-hill companies, inc....
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Copyright 2003 The McGraw-Hill Companies, Inc.
Copyright 2003 The McGraw-Hill Companies, Inc.
1
CH
AP
TE
R
Connectivity, the Wireless Revolution,
and Communications
7777computing ESSENTIALS
Copyright 2003 The McGraw-Hill Companies, Inc.
2
Competencies
Connectivity
Wireless Revolution
Communication systems
Connection devices
Transmissions and protocols
Network architecture
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3
Connectivity
Computer networks
that link people and
resources
Other computers
Large storage
devices
Internet
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4
Wireless Revolution Wireless and mobile
telephones Most dramatic change in
connectivity Connected all the time
anywhere Originally voice
communication Computer communications
Bluetooth Device connections
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Communication Systems
Electronic systems that transmit and receive information
Basic elements Sending/Receiving device Communication channel Connection devices Data transmission specifications
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Communication Channels
Essential element of communication system
Two categories
Physical connection
Wireless connection
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Wired Connections Telephone lines
Twisted pair Old standard
• Coaxial cable– Single solid-copper core– 80 times faster
• Fiber-optic cable– Light through glass– 26,000 times faster
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Wireless Connections
Microwave High-frequency radio waves Line-of-sight communication Relayed
Satellite Microwave relay stations Geostationary Large volume of data
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9
Connection Devices
Modulator-demodulator Converts analog signal to digital signal
Speed in bits per second (bps) External Internal PC Card Wireless
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Connection Types Dial-up service
Most popular, but slow T1 – T4 lines
Special high-speed lines Digital subscriber line (DSL)
Uses existing phone lines, fast Cable
Existing television cables Satellite/air connection services
Slower than DSL, but faster than dial-up
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Data Transmission
Bandwidth How much information can be transmitted at
one time
Protocol Specific rules guiding the exchange of
information
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Bandwidth Measurement of capacity of the
communication channel Categories
VoicebandStandard phone line, dial-up
Medium bandSpecial leased lines
BroadbandHigh capacity transmissionsDSL, cable, satellite
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Data Transmission Direction
Simplex
One direction only
Half-duplex
One direction at a time
Full-duplex
Both direction simultaneously
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Protocols Set of communication rules for exchange of
information Transmission control protocol/Internet
protocol (TCP/IP) Identification
IP AddressDomain name system (DNS)
ReformattingReassemble packets
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Networks Two or more connected computers that share
information and resources Node
Device connected to a network Client
Node that requests and uses resources available from other nodes
Server Node that shares resources with other
nodes
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More Network Terms
Network operating system (NOS) Software to control and coordinate activities
between nodes on a network Distributed processing
Computing power located and shared at different locations
Host computer Large centralized computer, usually a
mainframe
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Network Architecture Arrangement of network communication
channel Coordinates and shares resources Topology
Star network Bus network Ring network Hierarchical
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Star Network
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Bus Network
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Ring Network
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Hierarchical Network
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Strategies
Ways to coordinate sharing of resources
Most common
Terminal network system
Peer-to-peer network system
Client/Server network system
Enterprise computing
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Network Types
Networks differ in geographical size
Types of networks
Local Area Network (LAN)
Metropolitan Area Network (MAN)
Wide Area Network (WAN)
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Local Area Networks
Computers and devices linked in close
proximity to each other
Typically use a bus form of organization
Network gateways
Network bridge
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Metropolitan Area Networks
Link nodes and resources within the
geographical bounds of a city
Link between buildings
Cellular phones can extend the reach of a MAN
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Wide Area Networks
Countrywide and worldwide network
Use microwave relays and satellites
Internet
Widest of all WAN
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Look to Future
Wireless robotic car Toyota and Sony collaboration
Pod Connects wirelessly to portable terminal
Download songs from Internet Use GPS to determine location Communicate with other cars
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