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8.1 © 2004 by Prentice Hall
TELECOMMUNICATIONSTELECOMMUNICATIONS
AND AND
NETWORKSNETWORKS
8.2 © 2004 by Prentice Hall
• 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
8.3 © 2004 by Prentice Hall
• 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
8.4 © 2004 by Prentice Hall
• Managing LANsManaging LANs
• Managing bandwidthManaging bandwidth
MANAGEMENT CHALLENGES
8.5 © 2004 by Prentice Hall
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
8.6 © 2004 by Prentice Hall
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
8.7 © 2004 by Prentice Hall
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
Components of a Telecommunications System
Figure 8-1
8.8 © 2004 by Prentice Hall
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
• 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
8.9 © 2004 by Prentice Hall
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
• 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
8.10 © 2004 by Prentice Hall
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
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
8.11 © 2004 by Prentice Hall
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
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 communications
ModemModem
• 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
8.12 © 2004 by Prentice Hall
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
Functions of the Modem
Figure 8-2
8.13 © 2004 by Prentice Hall
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
• 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
8.14 © 2004 by Prentice Hall
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
• 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
8.15 © 2004 by Prentice Hall
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
Frequency Ranges for Communications Media and Devices
Figure 8-3
8.16 © 2004 by Prentice Hall
Figure 8-4
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
Amoco’s Satellite Transmission System
8.17 © 2004 by Prentice Hall
COMPONENTS AND FUNCTIONS OF A TELECOMMUNICATIONS SYSTEM
• Front-end processor:Front-end processor: Manages Manages communications for the host computercommunications for 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
8.18 © 2004 by Prentice Hall
COMMUNICATIONS NETWORKS
• 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
8.19 © 2004 by Prentice Hall
A Star Network Topology
COMMUNICATIONS NETWORKS
Figure 8-5
8.20 © 2004 by Prentice Hall
A Bus Network Topology
COMMUNICATIONS NETWORKS
Figure 8-6
8.21 © 2004 by Prentice Hall
A Ring Network Topology
COMMUNICATIONS NETWORKS
Figure 8-7
8.22 © 2004 by Prentice Hall
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)
COMMUNICATIONS NETWORKS
8.23 © 2004 by Prentice Hall
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
Private Branch Exchanges, Local Area Networks (LANs), and Wide Area Networks (WANs)
COMMUNICATIONS NETWORKS
8.24 © 2004 by Prentice Hall
COMMUNICATIONS NETWORKS
A Local Area Network (LAN)
Figure 8-8
8.25 © 2004 by Prentice Hall
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, cost, high-speed mobile Internet access, links work groupslinks work groups
• Bluetooth standard: Up to 720 Kbps, small Bluetooth standard: Up to 720 Kbps, small personal area networkspersonal area networks
Private Branch Exchanges, Local Area Networks (LANs), and Wide Area Networks (WANs)
COMMUNICATIONS NETWORKS
8.26 © 2004 by Prentice Hall
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
Private Branch Exchanges, Local Area Networks (LANs), and Wide Area Networks (WANs)
COMMUNICATIONS NETWORKS
8.27 © 2004 by Prentice Hall
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
COMMUNICATIONS NETWORKS
8.28 © 2004 by Prentice Hall
Packed-Switched Networks and Packet Communications
Figure 8-9
COMMUNICATIONS NETWORKS
8.29 © 2004 by Prentice Hall
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
COMMUNICATIONS NETWORKS
8.30 © 2004 by Prentice Hall
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
ELECTRONIC COMMERCE AND ELECTRONIC BUSINESS TECHNOLOGIES
8.31 © 2004 by Prentice Hall
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
8.32 © 2004 by Prentice Hall
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
Electronic Commerce and Electronic Business Technologies
ELECTRONIC COMMERCE AND ELECTRONIC BUSINESS TECHNOLOGIES
8.33 © 2004 by Prentice Hall
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
Electronic Commerce and Electronic Business Technologies
ELECTRONIC COMMERCE AND ELECTRONIC BUSINESS TECHNOLOGIES
8.34 © 2004 by Prentice Hall
• 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 COMMERCE AND ELECTRONIC BUSINESS TECHNOLOGIES
8.35 © 2004 by Prentice Hall
Electronic Data Interchange (EDI)
Figure 8-10
ELECTRONIC COMMERCE AND ELECTRONIC BUSINESS TECHNOLOGIES
8.36 © 2004 by Prentice Hall
TELECOMMUNICATIONSTELECOMMUNICATIONS
AND AND
NETWORKSNETWORKS