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88TELECOMMUNICATIONSTELECOMMUNICATIONS
AND NETWORKSAND NETWORKS
LEARNING OBJECTIVES
DESCRIBE COMPONENTS OF TELECOMMUNICATIONS SYSTEM
CALCULATE CAPACITY OF TELECOMMUNICATIONS CHANNELS & EVALUATE TRANSMISSION MEDIA
COMPARE TYPES OF NETWORKS & NETWORK SERVICES
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LEARNING OBJECTIVES
COMPARE ALTERNATIVE NETWORK SERVICES
IDENTIFY APPLICATIONS FOR SUPPORTING ELECTRONIC COMMERCE, BUSINESS
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MANAGEMENT CHALLENGES
TELECOMMUNICATIONS REVOLUTION
COMPONENTS, FUNCTIONS OF TELECOMMUNICATIONS SYSTEM
COMMUNICATIONS NETWORKS ELECTRONIC COMMERCE &
ELECTRONIC BUSINESS TECHNOLOGIES
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MANAGEMENT CHALLENGES
1. MANAGING LOCAL AREA NETWORKS: Must be carefully administered, monitored, vulnerable to interruption, data loss, viruses
2. MANAGING BANDWIDTH: While costs per unit are dropping and capacity is growing, sudden demand can overwhelm system
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TELECOMMUNICATIONS
COMMUNICATING INFORMATIONVIA ELECTRONIC MEANSOVER SOME DISTANCE
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INFORMATION SUPERHIGHWAY
NATIONAL / WORLDWIDEHIGH SPEED
DIGITAL TELECOMMUNICATIONSACCESSIBLE BY GENERAL PUBLIC
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SYSTEM COMPONENTS
COMPUTERS TERMINALS: Input / output devices COMMUNICATIONS CHANNELS PROCESSORS: Modems, multiplexers,
front-end processors COMMUNICATIONS SOFTWARE Routers, Hubs and Switches
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PROTOCOL
RULES & PROCEDURESTO GOVERN TRANSMISSION
BETWEEN COMPONENTS IN A NETWORK
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ANALOG SIGNAL CONTINUOUS WAVEFORM PASSES THRU SYSTEM VOICE COMMUNICATIONS
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DIGITAL SIGNAL
DISCRETE WAVEFORM TWO DISCRETE STATES:
1-BIT & 0-BIT ON / OFF PULSE
DATA COMMUNICATION USES MODEM TO TRANSLATE
ANALOG TO DIGITAL, DIGITAL TO ANALOG
*0010111010011101001010101110111100100010000101111010110100111010010010110010101101100
COMMUNICATION CHANNELSMEANS BY WHICH DATA ARE
TRANSMITTED: TWISTED WIRES: Copper Wires COAXIAL CABLE: Insulated Copper Wires FIBER-OPTIC CABLE MICROWAVE Radio Frequency
*
SUPER CLEAR GLASS STRANDS FAST, LIGHT, DURABLE TRILLIONS OF BITS PER SECOND, FULL
DUPLEX EXPENSIVE, HARDER TO INSTALL OFTEN USED AS BACKBONE OF
NETWORKS*
FIBER OPTICS
SIGNALSIGNAL LASERLASER CABLECABLE PHOTOPHOTODETECTORDETECTOR SIGNALSIGNAL
BACKBONE: Fiber optics cable carries light signals to distribution nodes, which use copper wires to user
DENSE WAVE DIVISION MULTIPLEXING (DWDM): Next-generation, uses many colors, (up to 160) each a channel, increases capacity of a fiber to 6.4 terabits per second
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FIBER OPTICS
WIRELESS TRANSMISSION TECHNOLOGIES PAGERS: Small pager beeps when
receives short message CELLULAR TELEPHONE: Device uses
radio waves to reach antennas within areas called cells
MOBILE DATA NETWORKS: Radio - based data network using hand-held computers, cheap, efficient
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WIRELESS TRANSMISSION TECHNOLOGIES
PERSONAL COMMUNICATION SERVICE: Cellular; lower power; higher frequency. Smaller phones not shielded by buildings, tunnels
PERSONAL DIGITAL ASSISTANT: Pen sized, hand-held, digital
communicator SMART PHONE: Wireless, voice, text,
Internet*
ORBITING SATELLITES
UPLINKUPLINK
MICROWAVE MICROWAVE TRANSMISSIONTRANSMISSION
DOWNLINKDOWNLINK
TRANSMISSION SPEED: Bits per Second (BPS) or Baud
BANDWIDTH: Capacity of Channel; Difference between Highest & Lowest Frequencies
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COMMUNICATIONS 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 MEDIA
COMMUNICATIONS PROCESSORS
FRONT- END PROCESSOR: Minicomputer manages communication for host computer
CONCENTRATOR: Computer collects messages for batch transmission to host computer
CONTROLLER: Computer controls interface between CPU and peripheral devices
MULTIPLEXER: Allows channel to carry multiple sources simultaneously
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NETWORK TOPOLOGIES
HOSTHOST
USERUSER
USERUSER
USERUSER USERUSER
STARHost mainframe computers use this with terminals.
NETWORK TOPOLOGIES
BUSCollision detection is required for multiple devices to share the same bus. This creates some inefficiency.
USERUSER
USERUSER
USERUSER
USERUSER
USERUSER
USERUSER
Network devices may look like a
star configuration
NETWORK TOPOLOGIES
DeviceDevice
DeviceDevice
DeviceDevice
DeviceDevice
RINGA token is passed from device to device. Synchronizing access to the ring. Single rings exists in older systems. Newer double rings are more reliable.
LOCAL NETWORKS
PRIVATE BRANCH EXCHANGE (PBX): firm’s central switching system
LOCAL AREA NETWORK (LAN): dedicated channels; limited distance (less than 2000 foot radius); higher capacity than PBX. Can share expensive hardware & software
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LOCAL AREA NETWORK (LAN)
GATEWAY: Connection to other networks ROUTER: Forwards data to other networks NETWORK OPERATING SYSTEM (NOS):
Manages file server; routes communications on network
PEER - TO - PEER: In some small networks all computers have equal power
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Network spans large geographic distances. Can include cable, satellite, microwave
SWITCHED LINES: Route determined by current traffic
DEDICATED LINES: Constantly available for high-volume traffic
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WIDE - AREA NETWORK (WAN)
VALUE-ADDED NETWORK (VAN) PRIVATE, MULTIPATH, DATA ONLY 3rd PARTY MANAGED USED BY SEVERAL ORGANIZATIONS SUBSCRIPTION BASIS
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NETWORK SERVICES
PACKET SWITCHING FRAME RELAY ASYNCHRONOUS TRANSFER MODE (ATM) INTEGRATED SERVICES DIGITAL
NETWORK (ISDN) SYMMETRIC DIGITAL SUBSCRIBER LINE CABLE MODEM T1 LINE
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PACKET SWITCHING (X.25) FORM OF Value Added Network BREAKS DATA BLOCKS INTO SMALL
PACKETS (e.g.: 128 Bytes) PACKETS ROUTED BY MOST
ECONOMICAL MEANS REASSEMBLED AT DESTINATION
*
FRAME RELAY PACKAGES DATA INTO BLOCKS
(FRAMES) HIGH-SPEED TRANSMISSION RELIABLE LINES NO ERROR-CORRECTION
ROUTINES*
ASYNCHRONOUS TRANSFER MODE (ATM)
CELL: 53 Groups of 8 Bytes Each USES FIBER OPTICS CABLE INDEPENDENT OF VENDOR
HARDWARE SPEEDS CAN TIE LAN TO WAN
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INTEGRATED SERVICES DIGITAL NETWORK (ISDN)
INTERNATIONAL STANDARD FOR TRANSMITTING VOICE, VIDEO,
DATAOVER PUBLIC TELEPHONE LINES
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OTHER SERVICES:
DIGITAL SUBSCRIBER LINE (DSL): enhancing capacity over copper telephone lines
CABLE MODEM: modem for cable TV for high-speed access to Internet
T1 LINE: dedicated telephone connection, 24 channels @ 1.544 megabits per second
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OTHER SERVICES:
BROADBAND: High-speed transmission, multiple channels
NETWORK CONVERGENCE: Enables simultaneous transmission of voice, data, video. Attractive for multimedia applications: Video collaboration, voice-data call centers, distance learning, unified messaging
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E-COMMERCE & E-BUSINESS TECHNOLOGIES
ELECTRONIC MAIL (e-mail) GROUPWARE VOICE MAIL FACSIMILE MACHINES (fax) TELECONFERENCING DATACONFERENCING VIDEOCONFERENCING
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E-COMMERCE & E-BUSINESS TECHNOLOGIES
DIGITAL INFORMATION SERVICES: Commercial service provides desired mix
DISTANCE LEARNING: Education, training delivered over a distance, can include printed material, teleconferencing, interactive multimedia, Web sites
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COMMERCIAL DIGITAL INFORMATION SERVICES
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 (EDI)
COMPUTER - TO - COMPUTEREXCHANGE BETWEEN TWO
ORGANIZATIONSOF STANDARD BUSINESS TRANSACTION DOCUMENTS
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COMPUTER COMPUTER
SELLER CUSTOMER
ORDERS, PAYMENTS
SHIPPING NOTICES, PRICE
UPDATES, INVOICES
88TELECOMMUNICATIONSTELECOMMUNICATIONS
AND NETWORKSAND NETWORKS
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