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Connectivity, the Wireless

Revolution, and Communications

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Objectives

• Connectivity

• Impact of wireless communications

• Elements of communications system– Channels– Connections– Transmissions– Network architecture and type

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Communication Channels

• Essential element of system

• Two categories

– Physical connection

– Wireless connection

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Wired Connections

• Telephone lines

•Coaxial cable

•Fiber-optic cable

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fiber-optic - 26,000

coaxial - 80

twisted-pair - 1

Number of Connections

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Wireless Connections

• Microwave

• Satellite

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Connection Devices

• Internal

• External

• Wireless

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Bandwidth

• Voiceband

• Medium band

• Broadband

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Serial vs. Parallel

• Serial

– Continuous stream of bits

• Parallel

– Simultaneously flow of bits

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Data Transmission Direction

• Simplex

• Half-duplex

• Full-duplex

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Protocols

• Set of communication rules

• Standard for Internet: TCP/IP

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Network Architecture

• Arrangement of

communication channel

• How resources shared

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Common Terms

• Node

• Client

• Server

• NOS

• Distributed processing

• Host computer

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Topology

• Star

• Bus

• Ring

• 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

• Terminal system

• Peer-to-peer system

• Client/Server system

• Enterprise computing

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Network Types

• LAN

• MAN

• WAN

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Look to Future

• Teledisc Corporation– Microsoft and Cellular

Communications

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