Transcript CHAP9

9.1
INFORMATION SYSTEM
BUSINESS
CHALLENGE
MANAGEMENT
INFORMATION
INFORMATION
BUSINESS
SYSTEM
SOLUTIONS
TECHNOLOGY
SELECTING A
TELECOMMUNICATIONS PLATFORM
ORGANIZATION
9.2
MANAGING LOCAL AREA NETWORKS
TELECOMMUNICATIONS
• COMMUNICATING INFORMATION
• VIA ELECTRONIC MEANS
• OVER SOME DISTANCE
*
9.3
INFORMATION SUPERHIGHWAY
•
•
•
•
9.4
NATIONAL / WORLDWIDE
HIGH SPEED
DIGITAL TELECOMMUNICATIONS
ACCESSIBLE BY GENERAL PUBLIC
*
COMMON BUSINESS TASKS
REQUIRING TELECOMMUNICATIONS
APPLICATION
EXAMPLE
REQUIREMENT
ONLINE DATA ENTRY
INVENTORY CONTROL
DIRECT RESPONSE REQUIRED
ON-LINE TEXT RETRIEVAL
HOSPITAL INFO SYSTEM
LIBRARY SYSTEMS
HIGH VOLUME REAL TIME RESPONSE
INQUIRY / RESPONSE
POINT-OF SALES
AIRLINE RESERVATIONS
CREDIT CHECKING
RESPONSE WITHIN SECONDS
ADMINISTRATIVE MESSAGES
ELECTRONIC MAIL
SHORT RESPONSE / DELIVERY TIMES
PROCESS CONTROL
COMPUTER AIDED
MANUFACTURING : NUMERIC
MACHINE CONTROL
INTERCOMPUTER DATA
EXCHANGE
ELECTRONIC FUNDS TRANSFER
9.5
CONTINUOUS INPUT / ONLINE
RESPONSES
BURST TRANSFER OF LARGE DATA
BLOCKS ON-LINE IMMEDIATE RESPONSE
SYSTEM COMPONENTS
•
•
•
•
COMPUTERS
TERMINALS (Input / Output Devices)
COMMUNICATIONS CHANNELS
PROCESSORS (Modems; Multiplexers;
SYSTEM
SYSTEM
Front-end Processors)
• NETWORK SOFTWARE
PROCESS
* INPUT
FEEDBACK
9.6
OUTPUT
PROTOCOL
RULES & PROCEDURES
TO GOVERN TRANSMISSION
BETWEEN COMPONENTS
IN A NETWORK
*
9.7
ANALOG SIGNAL
• CONTINUOUS WAVEFORM
• PASSES THRU SYSTEM
• VOICE COMMUNICATIONS
*
9.8
DIGITAL SIGNAL
• DISCRETE WAVEFORM
• TWO DISCRETE STATES:
– 1-BIT & 0-BIT
– ON / OFF PULSE
• DATA COMMUNICATION
*
9.9
COMMUNICATION CHANNELS
MEANS BY WHICH DATA ARE
TRANSMITTED:
• TWISTED PAIR (Copper Wires)
• COAXIAL CABLE: (Insulated Copper
Wires)
• FIBER-OPTIC CABLE
• WIRELESS
*
9.10
FIBER OPTICS
•
•
•
•
SUPER CLEAR GLASS STRANDS
OVER 4 MILLION MILES IN U.S.
NATION-WIDE BY 2015
UP TO TEN BILLION BITS PER
SECOND
• FULL DUPLEX
*
PHOTO
SIGNAL
9.11
LASER
CABLE
DETECTOR
SIGNAL
WIRELESS TRANSMISSION
(Megahertz)
• 105 - 108: AM Radio; Short Wave; FM;
VHF-TV
• 108 - 1010: UHF-TV, Cellular Phones,
RAM Mobile, Data, Cordless Phone,
Paging, Narrow Band PCS, Industrial
• 1010 - 1012: Radar, Microwave
• 1013 - 1014: Infra Red, Remote Control,
Wireless
9.12
*
WIRELESS TRANSMISSION
(Megahertz)
• 1015 - 1016: Visible Light; Fiber Optics
• 1018 - 1022: X-Ray, Gamma, Cosmic,
Personal Communication Services
(PCS)
*
9.13
LOW-ORBIT SATELLITE
MICROWAVE
TRANSMISSION
UPLINK
9.14
DOWNLINK
WIRELESS TRANSMISSION
TECHNOLOGIES
9.15
• PAGING SYSTEM: Small Page 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
*
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
*
9.16
COMMUNICATIONS CHANNELS
• TRANSMISSION SPEED: Bits per
Second (BPS) or Baud
• BANDWIDTH: Capacity of Channel;
Difference between Highest & Lowest
Frequencies
*
9.17
SPEEDS & COST OF MEDIA
MEDIUM
TWISTED PAIR
SPEED
300 BPS - 10 MBPS
MICROWAVE
256 KBPS - 100 MBPS
SATELLITE
256 KBPS - 100 MBPS
COAXIAL CABLE
56 KBPS - 200 MBPS
FIBER OPTICS
56 KBPS - 10 GBPS
BPS: BITS PER SECOND
KBPS: KILOBITS PER SECOND
MBPS: MEGABITS PER SECOND
GBPS: GIGABITS PER SECOND
9.18
COST
LOW
HIGH
TRANSMISSION MODES
• ASYNCHRONOUS: One Character at
a Time; Start, Stop, Parity Bits; Low
Speed
• SYNCHRONOUS: Timing Circuitry
determines Start & End of Block
Transmission; High Speed
*
9.19
TRANSMISSION DIRECTION
• SIMPLEX: One Direction Only
• HALF-DUPLEX: Can Flow Both
Ways; Only One Direction at a Time
• FULL-DUPLEX: Both Directions
Simultaneously
*
9.20
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
*
9.21
NETWORK TOPOLOGIES
USER
USER
STAR
9.22
HOST
USER
USER
NETWORK TOPOLOGIES
BUS
9.23
USER
USER
USER
USER
USER
USER
NETWORK TOPOLOGIES
USER
USER
RING
9.24
USER
USER
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
*
9.25
LOCAL AREA NETWORK
• FILE SERVER: Stores Programs,
Data; Determines Access to Network
• NETWORK OPERATING SYSTEM:
Manages File Server; Routes
Communications on Network
• GATEWAY: Connection to Other
Networks
*
9.26
LOCAL AREA NETWORK
• BASEBAND: Provides Single Path for
Transmitting either Text, Graphics,
Voice, or Video at One Time
• BROADBAND: Provides Several
Paths for Transmitting Several Types
of Data Simultaneously
*
9.27
WIDE - AREA NETWORK
• 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
*
9.28
VALUE-ADDED NETWORK
(VAN)
•
•
•
•
9.29
PRIVATE; MULTIPATH; DATA ONLY
3rd PARTY MANAGED
USED BY SEVERAL ORGANIZATIONS
SUBSCRIPTION BASIS
*
PACKET SWITCHING
• FORM OF VAN
• BREAKS DATA BLOCKS INTO
SMALL PACKETS (e.g.: 128 Bytes)
• PACKETS ROUTED BY MOST
ECONOMICAL MEANS
• REASSEMBLED AT DESTINATION
*
9.30
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
*
9.31
HOW ORGANIZATIONS USE
TELECOMMUNICATIONS
• FACILITATING APPLICATIONS
• ELECTRONIC DATA INTERCHANGE
• GROUPWARE
*
9.32
FACILITATING APPLICATIONS
•
•
•
•
•
•
•
9.33
ELECTRONIC MAIL (e-mail)
VOICE MAIL
FACSIMILE MACHINES (fax)
DIGITAL INFORMATION SERVICES
TELECONFERENCING
DATACONFERENCING
VIDEOCONFERENCING
*
9.34
DIGITAL INFORMATION SERVICES
PROVIDER
TYPE OF SERVICE
AMERICA ONLINE
GENERAL INTEREST / BUSINESS INFORMATION
COMPUSERVE
GENERAL INTEREST / BUSINESS INFORMATION
PRODIGY
GENERAL INTEREST / BUSINESS INFORMATION
DOW JONES NEWS RETRIEVAL BUSINESS / FINANCIAL INFORMATION
QUOTRON
FINANCIAL INFORMATION
DIALOG
BUSINESS / SCIENTIFIC / TECHNICAL INFORMATION
LEXIS
LEGAL RESEARCH
NEXIS
NEWS / BUSINESS INFORMATION
GROUPWARE
•
•
•
•
•
•
9.35
GROUP WRITING & COMMENTING
ELECTRONIC MAIL DISTRIBUTION
SCHEDULING MEETINGS
SHARED FILES & DATABASES
SHARED TIME LINES & PLANS
ELECTRONIC MEETINGS
*
MANAGEMENT ISSUES &
DECISIONS
TELECOMMUNICATIONS PLAN:
• KNOW LONG-RANGE PLANS
• AUDIT EXISTING CAPABILITIES
• IDENTIFY, PRIORITIZE CRITICAL
IMPROVEMENTS
• ENHANCE FIRM’S STRATEGIC POSITION
IMPLEMENT PLAN
*
9.36
IMPLEMENTATION FACTORS
•
•
•
•
•
•
•
•
9.37
DISTANCE
RANGE OF SERVICES
SECURITY
MULTIPLE ACCESS
UTILIZATION
COST
INSTALLATION
CONNECTIVITY
*
9.38