TELECOMMUNICATIONS AND NETWORKS

8.1 © 2004 by Prentice Hall

Management Information Systems 8/eManagement Information Systems 8/eChapter 8 Telecommunications and NetworksChapter 8 Telecommunications and Networks8

TELECOMMUNICATIONSTELECOMMUNICATIONS

AND AND

NETWORKSNETWORKS

Chapter


Management Information Systems 8/eManagement Information Systems 8/eChapter 8 Telecommunications and NetworksChapter 8 Telecommunications and Networks

• 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?

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



COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM

Telecommunications:Telecommunications:• Communication of information by Communication of information by

electronic meanselectronic means

• Includes digital data transmission Includes digital data transmission as well as voice transmissionas well as voice transmission




• 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 Transmits data coded into two

discrete states as 1-bits and 0-bitsdiscrete states as 1-bits and 0-bits• Used for data communicationsUsed for data communicationsModemModem• Translates computer’s digital Translates computer’s digital

signals into analog and vice versasignals into 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 speed:Transmission speed: Baud, bandwidth Baud, bandwidth

Communications Channels




Frequency Ranges for Communications Media and Devices

Figure 8-3



Figure 8-4


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 Enables single communication channel to carry data transmissions channel to carry data transmissions

Communications Processors and Software



COMMUNICATIONS NETWORKS

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

• Require their own dedicated channels Require their own dedicated channels

• Encompass a limited distanceEncompass a limited distance

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






A Local Area Network (LAN)

Figure 8-8



Wireless LANsWireless LANs

• Wi-Fi (802.11b) standard: Up to 11 Mbps, low Wi-Fi (802.11b) standard: Up to 11 Mbps, low cost, high-speed mobile Internet access, links cost, high-speed mobile Internet access, links work groupswork groups

• Bluetooth standard: Up to 720 Kbps, small Bluetooth standard: Up to 720 Kbps, small personal area networkspersonal area networks





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

• Span large geographical distanceSpan large geographical distance

• Consist of variety of cable, satellite, and Consist of variety of cable, satellite, and microwave technologiesmicrowave technologies

• Switched lines, dedicated linesSwitched lines, dedicated lines





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

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

Other Network ServicesOther Network Services

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

• Integrated Services Digital Network (ISDN), Digital Integrated Services Digital Network (ISDN), Digital subscriber line (DSL), Cable modems, T1 line - subscriber line (DSL), Cable modems, T1 line - BroadbandBroadband

Network Services and Broadband Technologies




Packed-Switched Networks and Packet Communications

Figure 8-9




Converged networkConverged network• Enables voice, video and data to run Enables voice, video and data to run

over a single networkover a single 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 TechnologiesELECTRONIC 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

Electronic Commerce and Electronic Business Technologies

ELECTRONIC COMMERCE AND ELECTRONIC BUSINESS TECHNOLOGIES



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 (EDI)




Electronic Data Interchange (EDI)

Figure 8-10



Management Information Systems 8/eManagement Information Systems 8/eChapter 8 Telecommunications and NetworksChapter 8 Telecommunications and Networks8

TELECOMMUNICATIONSTELECOMMUNICATIONS

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TELECOMMUNICATIONS AND NETWORKS

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