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Telecommunications

Telecommunications. Chapter 5. The Components of an Information System. Importance of Telecommunications. Work Group Communication E-mail Video conferencing Emerging Business Applications Electronic Commerce Electronic Data Interchange (EDI) Rapid rate of change in technology.

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Telecommunications

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  1. Telecommunications Chapter 5

  2. The Components of an Information System

  3. Importance of Telecommunications • Work Group Communication • E-mail • Video conferencing • Emerging Business Applications • Electronic Commerce • Electronic Data Interchange (EDI) • Rapid rate of change in technology

  4. Data Communication • All communications require three things: • Senders and receivers that have something to share • Coded by sender • Decoded by receiver • A pathway or transmission media to send the message • Rules or protocols of communication

  5. Human vs Computer Communication

  6. Computer Networks • Computers and other devices connected by a communications channel • Share files and other resources between users • Channel: the transmission media • Bandwidth: carrying capacity of the media • Protocols: the physical and logical rules for transmission

  7. Remaining Topics • Computing Network Models • Classes of Computer Networks • Building Blocks of Computer Networks

  8. Computing Network Models • Centralized computing • Uses mainframes and “dumb” terminals • Distributed computing • Uses separate computers • Collaborative computing • Uses two or more networked computers • Networks today include all three models

  9. Centralized Computing Model

  10. Distributed Computing Model

  11. Collaborative Computing Model

  12. Computing Network Models • Centralized, distributed, collaborative • Classes of Computer Networks • Building Blocks of Computer Networks

  13. Classes of Computer Networks • Private Branch Exchange (PBX) • A privately owned telephone switch • Local Area Network (LAN) • Usually confined to a single building or site • Wide Area Network (WAN) • Enterprise network - one organization • Global network

  14. Private Branch Exchange

  15. Local Area Network

  16. Enterprise Network

  17. Computing Network Models • Centralized, distributed, collaborative • Classes of Computer Networks • PBX, LAN, WAN (enterprise & global) • Building Blocks of Computer Networks

  18. Building Blocks of Computer Networks • Servers, Clients, and Peers • Network Services • Transmission Media • Network Topologies • Network Access Control Methods • Major Standards

  19. Servers, Clients, and Peers • Server-centric networks • Server • A network computer that makes services available to users • Client • Uses services provided by a server • Peer-to-peer networks • Allow any computer or device to provide and request services

  20. Servers, Clients, and Peers

  21. Computing Network Models • Centralized, distributed, collaborative • Classes of Computer Networks • PBX, LAN, WAN (enterprise & global) • Building Blocks of Computer Networks • Server-centric/peer-to-peer • Network Services • Transmission Media • Network Topologies • Network Access Control Methods • Major Standards

  22. Network Services • Offered by the network operating system • File services • Store, retrieve, and move data • Print services • Control access to printers and fax machines • Message services • Deal with communication between network users • Application services • Run software for network clients

  23. Computing Network Models • Centralized, distributed, collaborative • Classes of Computer Networks • PBX, LAN, WAN (enterprise & global) • Building Blocks of Computer Networks • Server-centric/peer-to-peer • Network Services • Transmission Media • Network Topologies • Network Access Control Methods • Major Standards

  24. Transmission Media • The physical pathway that carries signals • Media characteristics • Bandwidth - transmission capacity stated in megabits per second (Mbps) • Attenuation - weakening of signal over distance • EMI - electromagnetic interference • Two forms • Cable media • Wireless media

  25. Cable Media • Twisted Pair • Two or more pairs of insulated copper wires • Coaxial • Inner copper conductor surrounded by plastic insulation with outer braided foil shield • Fiber Optic • Uses pulses of light to send data • Glass or plastic core surrounded by cladding with a tough outer sheath

  26. Wireless Media • Infrared Line of Sight • Light waves transmit data on unobstructed path • High-Frequency Radio • Radio signals up to 39.6 meters • Microwave Line of Sight • Terrestrial uses earth-based antennas • Satellite sends signals between antennas on earth and orbiting satellites

  27. Computing Network Models • Centralized, distributed, collaborative • Classes of Computer Networks • PBX, LAN, WAN (enterprise & global) • Building Blocks of Computer Networks • Server-centric/peer-to-peer • Network Services • Transmission Media (Cable, Wireless) • Network Topologies • Network Access Control Methods • Major Standards

  28. Network Topologies • Star Network • All nodes attached to center a hub • Messages must pass through the hub • Ring Network • A closed loop • Messages move in one direction • Bus Network • An open-ended line • Nodes receive message at the same time

  29. Star Network

  30. Ring Network

  31. Bus Network

  32. Computing Network Models • Centralized, distributed, collaborative • Classes of Computer Networks • PBX, LAN, WAN (enterprise & global) • Building Blocks of Computer Networks • Server-centric/peer-to-peer • Network Services • Transmission Media (Cable, Wireless) • Network Topologies (Star, Ring, Bus) • Network Access Control Methods • Major Standards

  33. Network Access Control Methods • Distributed Access Control • Token passing • Circulating electronic token prevents collisions • Must possess the token to transmit a message • Random Access Control • CSMA/CD • “Listen” for quiet line; then send message • Collision occurs with simultaneous messages • Must wait and resend

  34. Token Ring Operation

  35. Computing Network Models • Centralized, distributed, collaborative • Classes of Computer Networks • PBX, LAN, WAN (enterprise & global) • Building Blocks of Computer Networks • Server-centric/peer-to-peer • Network Services • Transmission Media (Cable, Wireless) • Network Topologies (Star, Ring, Bus) • Network Access Control Methods (Distributed—Token passing, Random) • Major Standards

  36. The OSI Model

  37. The OSI Model andMessage Passing

  38. Network Operating Systems • Client/server architecture LANs • The system software runs on the file server • Part of the NOS runs on each workstation • Peer-to-peer networks • NOS is installed on each attached workstation • Runs on top of the local operating system

  39. Computing Network Models • Centralized, distributed, collaborative • Classes of Computer Networks • PBX, LAN, WAN (enterprise & global) • Building Blocks of Computer Networks • Server-centric/peer-to-peer • Network Services (File, print, message, application) • Transmission Media (Cable, Wireless) • Network Topologies (Star, Ring, Bus) • Network Access Control Methods (Distributed -Token passing, Random) • Major Standards (The OSI Model)

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