1 / 40

Telecommunications

This chapter discusses the essential components of telecommunications and computer networks, exploring the importance of effective communication in information systems. Key topics include the roles of senders, receivers, and coded messages within a transmission medium, along with rules and protocols for successful data exchange. It covers network models (centralized, distributed, collaborative), classes of networks (PBX, LAN, WAN), and the infrastructure necessary for efficient communication, such as servers, clients, transmission media, and network topologies.

damia
Télécharger la présentation

Telecommunications

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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)

More Related