c h a p t e r

88TELECOMMUNICATIONSTELECOMMUNICATIONS

AND NETWORKSAND NETWORKS

LEARNING OBJECTIVESLEARNING OBJECTIVES

• DESCRIBE COMPONENTS OF DESCRIBE COMPONENTS OF TELECOMMUNICATIONS SYSTEMTELECOMMUNICATIONS SYSTEM

• CALCULATE CAPACITY OF CALCULATE CAPACITY OF TELECOMMUNICATIONS CHANNELS & TELECOMMUNICATIONS CHANNELS & EVALUATE TRANSMISSION MEDIAEVALUATE TRANSMISSION MEDIA

• COMPARE TYPES OF COMPARE TYPES OF NETWORKS & NETWORKS & NETWORK SERVICESNETWORK SERVICES

**

LEARNING OBJECTIVESLEARNING OBJECTIVES

• COMPARE ALTERNATIVE COMPARE ALTERNATIVE NETWORK SERVICESNETWORK SERVICES

• IDENTIFY APPLICATIONS FOR IDENTIFY APPLICATIONS FOR SUPPORTING ELECTRONIC SUPPORTING ELECTRONIC COMMERCE, BUSINESSCOMMERCE, BUSINESS

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MANAGEMENT CHALLENGESMANAGEMENT CHALLENGES

• TELECOMMUNICATIONS REVOLUTIONTELECOMMUNICATIONS REVOLUTION• COMPONENTS, FUNCTIONS OF COMPONENTS, FUNCTIONS OF

TELECOMMUNICATIONS SYSTEMTELECOMMUNICATIONS SYSTEM• COMMUNICATIONS NETWORKSCOMMUNICATIONS NETWORKS• ELECTRONIC COMMERCE & ELECTRONIC COMMERCE &

ELECTRONIC BUSINESS TECHNOLOGIESELECTRONIC BUSINESS TECHNOLOGIES

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MANAGEMENT CHALLENGESMANAGEMENT CHALLENGES

1. MANAGING LOCAL AREA NETWORKS:1. MANAGING LOCAL AREA NETWORKS: Must be carefully administered, Must be carefully administered, monitored, vulnerable to interruption, data monitored, vulnerable to interruption, data loss, virusesloss, viruses

2. MANAGING BANDWIDTH:2. MANAGING BANDWIDTH: While costs per While costs per unit are dropping and capacity is growing, unit are dropping and capacity is growing, sudden demand can overwhelm systemsudden demand can overwhelm system

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TELECOMMUNICATIONSTELECOMMUNICATIONS

COMMUNICATING INFORMATIONCOMMUNICATING INFORMATION

VIA ELECTRONIC MEANSVIA ELECTRONIC MEANS

OVER SOME DISTANCEOVER SOME DISTANCE

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INFORMATION SUPERHIGHWAYINFORMATION SUPERHIGHWAY

NATIONAL / WORLDWIDENATIONAL / WORLDWIDE

HIGH SPEEDHIGH SPEED

DIGITAL TELECOMMUNICATIONSDIGITAL TELECOMMUNICATIONS

ACCESSIBLE BY GENERAL PUBLICACCESSIBLE BY GENERAL PUBLIC

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SYSTEM COMPONENTSSYSTEM COMPONENTS

• COMPUTERSCOMPUTERS• TERMINALS:TERMINALS: Input / output devices Input / output devices• COMMUNICATIONS CHANNELSCOMMUNICATIONS CHANNELS• PROCESSORS:PROCESSORS: Modems, multiplexers, Modems, multiplexers,

front-end processorsfront-end processors• COMMUNICATIONS COMMUNICATIONS

SOFTWARESOFTWARE

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PROTOCOLPROTOCOL

RULES & PROCEDURESRULES & PROCEDURES

TO GOVERN TRANSMISSIONTO GOVERN TRANSMISSION

BETWEEN COMPONENTS BETWEEN COMPONENTS

IN A NETWORKIN A NETWORK

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ANALOG SIGNALANALOG SIGNAL

• CONTINUOUS WAVEFORMCONTINUOUS WAVEFORM

• PASSES THRU SYSTEMPASSES THRU SYSTEM

• VOICE COMMUNICATIONSVOICE COMMUNICATIONS

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DIGITAL SIGNALDIGITAL SIGNAL• DISCRETE WAVEFORMDISCRETE WAVEFORM• TWO DISCRETE STATES:TWO DISCRETE STATES:– 1-BIT & 0-BIT– ON / OFF PULSE

• DATA COMMUNICATIONDATA COMMUNICATION• USES MODEM TO TRANSLATE ANALOG USES MODEM TO TRANSLATE ANALOG

TO DIGITAL, DIGITAL TO ANALOGTO DIGITAL, DIGITAL TO ANALOG

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0010111010011101001010101110111100100010000101111010110100111010010010110010101101100

COMMUNICATION CHANNELSCOMMUNICATION CHANNELS

MEANS BY WHICH DATA ARE MEANS BY WHICH DATA ARE TRANSMITTED:TRANSMITTED:

• TWISTED WIRES:TWISTED WIRES: Copper WiresCopper Wires

• COAXIAL CABLE:COAXIAL CABLE: Insulated Copper Insulated Copper WiresWires

• FIBER-OPTIC CABLEFIBER-OPTIC CABLE

• MICROWAVEMICROWAVE

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• SUPER CLEAR GLASS STRANDSSUPER CLEAR GLASS STRANDS• FAST, LIGHT, DURABLEFAST, LIGHT, DURABLE• TRILLIONS OF BITS PER SECOND, FULL TRILLIONS OF BITS PER SECOND, FULL

DUPLEXDUPLEX• EXPENSIVE, HARDER TO INSTALLEXPENSIVE, HARDER TO INSTALL• OFTEN USED AS BACKBONE OF OFTEN USED AS BACKBONE OF

NETWORKSNETWORKS

**

FIBER OPTICSFIBER OPTICS

SIGNALSIGNAL LASERLASER CABLECABLE PHOTOPHOTODETECTORDETECTOR SIGNALSIGNAL

• BACKBONE:BACKBONE: Fiber optics cable carries Fiber optics cable carries light signals to distribution nodes, which light signals to distribution nodes, which use copper wires to useruse copper wires to user

• DENSE WAVE DIVISION MULTIPLEXING DENSE WAVE DIVISION MULTIPLEXING (DWDM):(DWDM): Next-generation, uses many Next-generation, uses many colors, (up to 160) each a channel, colors, (up to 160) each a channel, increases capacity of a fiber to 6.4 terabits increases capacity of a fiber to 6.4 terabits per secondper second

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FIBER OPTICSFIBER OPTICS

WIRELESS TRANSMISSION WIRELESS TRANSMISSION TECHNOLOGIESTECHNOLOGIES

• PAGERS:PAGERS: Small pager beeps when Small pager beeps when receives short messagereceives short message

• CELLULAR TELEPHONE:CELLULAR TELEPHONE: Device uses Device uses radio waves to reach antennas within radio waves to reach antennas within areas called cellsareas called cells

• MOBILE DATA NETWORKS:MOBILE DATA NETWORKS: Radio - Radio - based data network using hand-held based data network using hand-held computers, cheap, efficientcomputers, cheap, efficient

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WIRELESS TRANSMISSION WIRELESS TRANSMISSION TECHNOLOGIESTECHNOLOGIES

• PERSONAL COMMUNICATION SERVICE:PERSONAL COMMUNICATION SERVICE: Cellular; lower power; higher frequency. Cellular; lower power; higher frequency. Smaller phones not shielded by buildings, Smaller phones not shielded by buildings, tunnelstunnels

• PERSONAL DIGITAL ASSISTANT:PERSONAL DIGITAL ASSISTANT: Pen sized, hand-held, digital communicatorPen sized, hand-held, digital communicator

• SMART PHONE:SMART PHONE: Wireless, voice, text, Wireless, voice, text, InternetInternet

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ORBITING SATELLITESORBITING SATELLITES

UPLINKUPLINK

MICROWAVE MICROWAVE TRANSMISSIONTRANSMISSION

DOWNLINKDOWNLINK

• TRANSMISSION SPEED:TRANSMISSION SPEED: Bits per Bits per Second (BPS) or BaudSecond (BPS) or Baud

• BANDWIDTH:BANDWIDTH: Capacity of Channel; Capacity of Channel; Difference between Highest & Difference between Highest & Lowest FrequenciesLowest Frequencies

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COMMUNICATIONS CHANNELSCOMMUNICATIONS CHANNELS

MEDIUMMEDIUM SPEEDSPEED COSTCOST TWISTED WIRETWISTED WIRE 300 BPS - 10 MBPS300 BPS - 10 MBPS LOWLOW

MICROWAVEMICROWAVE 256 KBPS - 100 MBPS256 KBPS - 100 MBPS

SATELLITESATELLITE 256 KBPS - 100 MBPS256 KBPS - 100 MBPS

COAXIAL CABLECOAXIAL CABLE 56 KBPS - 200 MBPS56 KBPS - 200 MBPS

FIBER OPTICSFIBER OPTICS 500 KBPS - 6.4 TBPS500 KBPS - 6.4 TBPS HIGHHIGH BPS: BITS PER SECONDBPS: BITS PER SECOND KBPS: KILOBITS PS, MBPS: MEGABITS PS,KBPS: KILOBITS PS, MBPS: MEGABITS PS, GBPS: GIGABITS PS, TBPS: TERABITS PSGBPS: GIGABITS PS, TBPS: TERABITS PS

SPEEDS & COST OF MEDIASPEEDS & COST OF MEDIA

COMMUNICATIONS PROCESSORSCOMMUNICATIONS PROCESSORS

• FRONT- END PROCESSOR:FRONT- END PROCESSOR: Minicomputer Minicomputer manages communication for host computermanages communication for host computer

• CONCENTRATOR:CONCENTRATOR: Computer collects Computer collects messages for batch transmission to host messages for batch transmission to host computercomputer

• CONTROLLER:CONTROLLER: Computer controls interface Computer controls interface between CPU and peripheral devicesbetween CPU and peripheral devices

• MULTIPLEXER:MULTIPLEXER: Allows channel to carry Allows channel to carry multiple sources multiple sources simultaneouslysimultaneously

**

NETWORK TOPOLOGIESNETWORK TOPOLOGIES

HOSTHOST

USERUSER

USERUSER

USERUSER USERUSER

STAR

NETWORK TOPOLOGIESNETWORK TOPOLOGIES

BUS

USERUSER

USERUSER

USERUSER

USERUSER

USERUSER

USERUSER

NETWORK TOPOLOGIESNETWORK TOPOLOGIES

USERUSER

USERUSER

USERUSER

USERUSER

RING

LOCAL LOCAL NETWORKSNETWORKS

• PRIVATE BRANCH EXCHANGE (PBX):PRIVATE BRANCH EXCHANGE (PBX): firm’s central switching systemfirm’s central switching system

• LOCAL AREA NETWORK (LAN):LOCAL AREA NETWORK (LAN): dedicated dedicated channels; limited distance (less than 2000 channels; limited distance (less than 2000 foot radius); higher capacity than PBX. foot radius); higher capacity than PBX. Can share expensive hardware & softwareCan share expensive hardware & software

**

LOCAL LOCAL AREAAREA NETWORK (LAN) NETWORK (LAN)

• GATEWAY:GATEWAY: Connection to other networksConnection to other networks

• ROUTER:ROUTER: Forwards data to other networks Forwards data to other networks

• NETWORK OPERATING SYSTEM (NOS):NETWORK OPERATING SYSTEM (NOS): Manages file server; routes communications Manages file server; routes communications on networkon network

• PEER - TO - PEER:PEER - TO - PEER: In some small networks all In some small networks all computers have equal powercomputers have equal power

**

Network spans large geographic distances. Network spans large geographic distances. Can include cable, satellite, microwaveCan include cable, satellite, microwave

• SWITCHED LINES:SWITCHED LINES: Route determined Route determined by by current trafficcurrent traffic

• DEDICATED LINES:DEDICATED LINES: Constantly available Constantly available for high-volume trafficfor high-volume traffic

**

WIDE - AREA NETWORK (WAN)WIDE - AREA NETWORK (WAN)

VALUE-ADDED NETWORK VALUE-ADDED NETWORK (VAN)(VAN)

• PRIVATE, MULTIPATH, DATA ONLYPRIVATE, MULTIPATH, DATA ONLY

• 3rd PARTY MANAGED3rd PARTY MANAGED

• USED BY SEVERAL ORGANIZATIONSUSED BY SEVERAL ORGANIZATIONS

• SUBSCRIPTION BASISSUBSCRIPTION BASIS

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NETWORK SERVICESNETWORK SERVICES

• PACKET SWITCHINGPACKET SWITCHING• FRAME RELAYFRAME RELAY• ASYNCHRONOUS TRANSFER MODE ASYNCHRONOUS TRANSFER MODE (ATM)(ATM)• INTEGRATED SERVICES DIGITAL NETWORK INTEGRATED SERVICES DIGITAL NETWORK

(ISDN)(ISDN)• SYMMETRIC DIGITAL SUBSCRIBER LINESYMMETRIC DIGITAL SUBSCRIBER LINE• CABLE MODEMCABLE MODEM• T1 LINET1 LINE

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PACKET SWITCHINGPACKET SWITCHING (X.25)(X.25)

• FORM OF FORM OF VValue alue AAdded dded NNetworketwork

• BREAKS DATA BLOCKS INTO BREAKS DATA BLOCKS INTO SMALL PACKETS (e.g.: 128 Bytes)SMALL PACKETS (e.g.: 128 Bytes)

• PACKETS ROUTED BY MOST PACKETS ROUTED BY MOST ECONOMICAL MEANSECONOMICAL MEANS

• REASSEMBLED AT DESTINATIONREASSEMBLED AT DESTINATION

**

FRAME RELAYFRAME RELAY

• PACKAGES DATA INTO BLOCKS PACKAGES DATA INTO BLOCKS (FRAMES)(FRAMES)

• HIGH-SPEED TRANSMISSIONHIGH-SPEED TRANSMISSION

• RELIABLE LINESRELIABLE LINES

• NO ERROR-CORRECTION NO ERROR-CORRECTION ROUTINESROUTINES

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ASYNCHRONOUS TRANSFER ASYNCHRONOUS TRANSFER MODEMODE (ATM)(ATM)

• CELL:CELL: 53 Groups of 8 Bytes Each 53 Groups of 8 Bytes Each• USES FIBER OPTICS CABLEUSES FIBER OPTICS CABLE• INDEPENDENT OF VENDOR INDEPENDENT OF VENDOR

HARDWARE SPEEDSHARDWARE SPEEDS• CAN TIE LAN TO WANCAN TIE LAN TO WAN

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INTEGRATED SERVICES DIGITAL INTEGRATED SERVICES DIGITAL NETWORKNETWORK (ISDN)(ISDN)

INTERNATIONAL STANDARD FOR INTERNATIONAL STANDARD FOR TRANSMITTING VOICE, VIDEO, TRANSMITTING VOICE, VIDEO,

DATADATA

OVER PUBLIC TELEPHONE LINESOVER PUBLIC TELEPHONE LINES

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OTHER SERVICES:OTHER SERVICES:

• DIGITAL SUBSCRIBER LINE (DSL):DIGITAL SUBSCRIBER LINE (DSL): enhancing capacity over copper enhancing capacity over copper telephone linestelephone lines

• CABLE MODEM:CABLE MODEM: modem for cable TV for modem for cable TV for high-speed access to Internethigh-speed access to Internet

• T1 LINE:T1 LINE: dedicated telephone connection, dedicated telephone connection, 24 channels @ 1.544 megabits per second24 channels @ 1.544 megabits per second

**

OTHER SERVICES:OTHER SERVICES:

• BROADBAND:BROADBAND: High-speed transmission, High-speed transmission, multiple channelsmultiple channels

• NETWORK CONVERGENCE:NETWORK CONVERGENCE: Enables Enables simultaneous transmission of voice, simultaneous transmission of voice, data, video. Attractive for multimedia data, video. Attractive for multimedia applications: Video collaboration, voice-applications: Video collaboration, voice-data call centers, distance learning, data call centers, distance learning, unified messagingunified messaging

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E-COMMERCE & E-COMMERCE & E-BUSINESS TECHNOLOGIESE-BUSINESS TECHNOLOGIES

• ELECTRONIC MAIL (e-mail)ELECTRONIC MAIL (e-mail)• GROUPWAREGROUPWARE• VOICE MAILVOICE MAIL• FACSIMILE MACHINES (fax)FACSIMILE MACHINES (fax)• TELECONFERENCINGTELECONFERENCING• DATACONFERENCINGDATACONFERENCING• VIDEOCONFERENCINGVIDEOCONFERENCING

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E-COMMERCE & E-COMMERCE & E-BUSINESS TECHNOLOGIESE-BUSINESS TECHNOLOGIES

• DIGITAL INFORMATION SERVICES:DIGITAL INFORMATION SERVICES: Commercial service provides desired mixCommercial service provides desired mix

• DISTANCE LEARNING:DISTANCE LEARNING: Education, training Education, training delivered over a distance, can include delivered over a distance, can include printed material, printed material, teleconferencing, interactive teleconferencing, interactive multimedia, Web sitesmultimedia, Web sites

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COMMERCIAL DIGITAL INFORMATION COMMERCIAL DIGITAL INFORMATION SERVICESSERVICES

PROVIDER TYPE OF SERVICE

AMERICA ONLINE General interest / business information

PRODIGY General interest / business information

MICROSOFT NETWORK General interest / business information

DOW JONES NEWS RETRIEVAL Business / financial information

DIALOG Business / scientific / technical information

LEXIS Legal research

NEXIS News / business information

ELECTRONIC DATA INTERCHANGE ELECTRONIC DATA INTERCHANGE (EDI)(EDI)

COMPUTER - TO - COMPUTERCOMPUTER - TO - COMPUTER

EXCHANGE BETWEEN TWO EXCHANGE BETWEEN TWO ORGANIZATIONSORGANIZATIONS

OF STANDARD BUSINESS OF STANDARD BUSINESS TRANSACTION DOCUMENTSTRANSACTION DOCUMENTS

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COMPUTER COMPUTER

SELLER CUSTOMER

ORDERS, PAYMENTS

SHIPPING NOTICES, PRICE

UPDATES, INVOICES

c h a p t e r

88TELECOMMUNICATIONSTELECOMMUNICATIONS

AND NETWORKSAND NETWORKS