Chapter08: Telecommunications and networks

8.1 © 2003 by Prentice Hall

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TELECOMMUNICATIONSTELECOMMUNICATIONS

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NETWORKSNETWORKS

Chapter


• What technologies are used in What technologies are used in telecommunications systems?telecommunications systems?

• What telecommunications transmission What telecommunications transmission media should our organization use?media should our organization use?

• How should our organization design its How should our organization design its networks?networks?

Essentials of Management Information SystemsEssentials of Management Information SystemsChapter 8 Telecommunications and NetworksChapter 8 Telecommunications and Networks

OBJECTIVES


• What alternative network services are What alternative network services are available to our organization?available to our organization?

• What telecommunications applications What telecommunications applications can be used for electronic commerce and can be used for electronic commerce and electronic business?electronic business?


OBJECTIVES


• Managing LANsManaging LANs

• Managing bandwidthManaging bandwidth

MANAGEMENT CHALLENGES



THE TELECOMMUNICATIONS REVOLUTION

• Telecommunications:Telecommunications: Communication Communication of information by electronic meansof information by electronic means

• The marriage of computers and The marriage of computers and communications:communications: The 1996 The 1996 Telecommunications Deregulation and Telecommunications Deregulation and Reform ActReform Act

• The Information Superhighway:The Information Superhighway: High- High-speed digital telecommunications speed digital telecommunications networks, accessible by the general publicnetworks, accessible by the general public



COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM

• Computers to process informationComputers to process information

• Terminals or any input/output devices Terminals or any input/output devices that send or receive datathat send or receive data

• Communications processorsCommunications processors

• Communications softwareCommunications software


Telecommunications System Components




Components of a Telecommunications System

Figure 8-1



• Transmit informationTransmit information

• Establish interface between sender and Establish interface between sender and the receiverthe receiver

• Route messages along most efficient Route messages along most efficient pathspaths


Functions of Telecommunications Systems



• Perform elementary processing of Perform elementary processing of information information

• Perform editorial tasks on data Perform editorial tasks on data

• Convert message speed or formatConvert message speed or format

• Control flow of informationControl flow of information


Functions of Telecommunications Systems



Analog signalAnalog signal

• Continuous waveform Continuous waveform

• Passes through communications mediumPasses through communications medium

• Used for voice communicationsUsed for voice communications


Types of Signals: Analog and Digital



Digital signalDigital signal

• Discrete waveformDiscrete waveform

• Transmits data coded into two discrete Transmits data coded into two discrete states as 1-bits and 0-bitsstates as 1-bits and 0-bits

• Used for data communicationsUsed for data communications

ModemModem

• Translates computer’s digital signals Translates computer’s digital signals into analog and vice versainto analog and vice versa


Types of Signals: Analog and Digital




Functions of the Modem

Figure 8-2



• Twisted wire:Twisted wire: Telephone systemsTelephone systems

• Coaxial cable:Coaxial cable: Cable televisionCable television

• Fiber optics and optical networks:Fiber optics and optical networks: Dense wave division multiplexing (DWDM)Dense wave division multiplexing (DWDM)


Communications Channels



• Wireless transmission:Wireless transmission: Microwave, Microwave, Satellites, Paging systems, Cellular Satellites, Paging systems, Cellular telephones, Personal communication telephones, Personal communication Services, Personal digital assistants, Services, Personal digital assistants, Mobile data networksMobile data networks

• Transmission:Transmission: Baud, bandwidth Baud, bandwidth


Communications Channels




Frequency Ranges for Communications Media and Devices

Figure 8-3



Figure 8-4

COMMUNICATIONS NETWORKS

Amoco’s Satellite Transmission System



• Front-end processor:Front-end processor: Manages communications Manages communications for the host computerfor the host computer

• Concentrator:Concentrator: Collects and temporarily stores Collects and temporarily stores messagesmessages

• Controller:Controller: Supervises communication traffic Supervises communication traffic

• Multiplexer:Multiplexer: Enables single communication channel Enables single communication channel to carry data transmissions to carry data transmissions


Communications Processors and Software



• Star Network:Star Network: All computers and other devices All computers and other devices are connected to a central host computerare connected to a central host computer

• Bus Network:Bus Network: Links a number of computers by a Links a number of computers by a single circuit single circuit

• Ring Network:Ring Network: All computers are linked by a All computers are linked by a closed loop closed loop


Network Topologies



A Star Network Topology


Figure 8-5



A Bus Network Topology


Figure 8-6



A Ring Network Topology


Figure 8-7


Private Branch ExchangesPrivate Branch Exchanges

• Central switching system Central switching system

• Handle firm’s voice and digital Handle firm’s voice and digital communicationscommunications


Private Branch Exchanges, Local Area Networks (LANs), and Wide Area Networks (WANs)



Local Area NetworksLocal Area Networks

• Telecommunication networkTelecommunication network

• Require its own dedicated channels Require its own dedicated channels

• Encompass a limited distanceEncompass a limited distance

• Gateway, router, Network Operating System (NOS), Gateway, router, Network Operating System (NOS), peer-to-peerpeer-to-peer







A Local Area Network (LAN)

Figure 8-8


Wide Area Networks (WANs)Wide Area Networks (WANs)

• Telecommunication networkTelecommunication network

• Span large geographical distanceSpan large geographical distance

• Consist of variety of cable, satellite, and microwave Consist of variety of cable, satellite, and microwave technologiestechnologies

• Switched lines, dedicated linesSwitched lines, dedicated lines





Value-Added Networks (VANs)Value-Added Networks (VANs)

• Private, multipath, data-only, third-party-Private, multipath, data-only, third-party-managed network managed network

Other Network ServicesOther Network Services

• Packet switching, Frame Relay, Packet switching, Frame Relay, Asynchronous transfer mode (ATM)Asynchronous transfer mode (ATM)

• Integrated Services Digital Network (ISDN), Integrated Services Digital Network (ISDN), Digital subscriber line (DSL), Cable modems, Digital subscriber line (DSL), Cable modems, T1 line, BroadbandT1 line, Broadband


Network Services and Broadband Technologies




Packed-Switched Networks and Packet Communications

Figure 8-9



Converged networkConverged network• Network with technology Network with technology • Enables voice and data to run over a Enables voice and data to run over a

single networksingle network

Unified messagingUnified messaging• System combining voice messages, System combining voice messages,

email, and fax email, and fax


Network Convergence



Electronic Mail and GroupwareElectronic Mail and Groupware

• E-mail:E-mail: Eliminates telephone tag and Eliminates telephone tag and costly long-distance telephone chargescostly long-distance telephone charges

• Groupware:Groupware: Enables work groups at Enables work groups at different locations to participate in different locations to participate in discussion forums and work on shared discussion forums and work on shared documents and projectsdocuments and projects


Electronic Commerce and Electronic Business Technologies



Voice Mail and FaxVoice Mail and Fax

• Voice mail:Voice mail: Digitizes spoken message Digitizes spoken message and transmits it over a networkand transmits it over a network

• Fax:Fax: Digitizes and transmits documents Digitizes and transmits documents over telephone linesover telephone lines





Teleconferencing, data conferencing, Teleconferencing, data conferencing, and videoconferencingand videoconferencing• Teleconferencing:Teleconferencing: Ability to confer Ability to confer

with a group of people simultaneouslywith a group of people simultaneously

• Data conferencing:Data conferencing: Two or more users Two or more users can edit and modify data files can edit and modify data files simultaneouslysimultaneously

• Videoconferencing:Videoconferencing: Participants are Participants are able to see each other over video able to see each other over video screensscreens





Digital information services, distance Digital information services, distance

learning and E-Learninglearning and E-Learning

• Distance learning:Distance learning: Education or training Education or training delivered over a distance to individuals in delivered over a distance to individuals in one or more locationsone or more locations

• E-learning:E-learning: Instruction delivered online Instruction delivered online using the Internet or private networksusing the Internet or private networks





• Direct computer-to-computer exchange Direct computer-to-computer exchange between two organizations of standard between two organizations of standard business transaction documentsbusiness transaction documents


Electronic Data Interchange




Electronic Data Interchange (EDI)

Figure 8-10



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