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9.1
LEARNING OBJECTIVES
• DESCRIBE COMPONENTS OF
TELECOMMUNICATIONS SYSTEM
• CALCULATE CAPACITY OF
TELECOMMUNICATIONS CHANNELS
& EVALUATE TRANSMISSION MEDIA
• COMPARE TYPES OF
NETWORKS & NETWORK
SERVICES
9.2
*
LEARNING OBJECTIVES
• DESCRIBE CONNECTIVITY
NETWORK STANDARDS
• IDENTIFY APPLICATIONS FOR
SUPPORTING ELECTRONIC
COMMERCE, BUSINESS
• ANALYZE MANAGEMENT
PROBLEMS OF
NETWORKING
9.3
*
MANAGEMENT CHALLENGES
• TELECOMMUNICATIONS REVOLUTION
• COMPONENTS, FUNCTIONS OF
TELECOMMUNICATIONS SYSTEM
• COMMUNICATIONS NETWORKS
• ELECTRONIC COMMERCE, ELECTRONIC
BUSINESS TECHNOLOGIES
• MANAGEMENT ISSUES, DECISIONS
*
9.4
TELECOMMUNICATIONS
COMMUNICATING INFORMATION
VIA ELECTRONIC MEANS
OVER SOME DISTANCE
*
9.5
INFORMATION
SUPERHIGHWAY
NATIONAL / WORLDWIDE
HIGH SPEED
DIGITAL TELECOMMUNICATIONS
ACCESSIBLE BY GENERAL PUBLIC
• *
9.6
SYSTEM COMPONENTS
•
•
•
•
COMPUTERS
TERMINALS (Input / Output Devices)
COMMUNICATIONS CHANNELS
PROCESSORS (Modems; Multiplexers;
Front-end Processors)
• COMMUNICATIONS
SOFTWARE
SYSTEM
*
INPUT
PROCESS
FEEDBACK
9.7
OUTPUT
PROTOCOL
RULES & PROCEDURES
TO GOVERN TRANSMISSION
BETWEEN COMPONENTS
IN A NETWORK
*
9.8
ANALOG SIGNAL
• CONTINUOUS WAVEFORM
• PASSES THRU SYSTEM
• VOICE COMMUNICATIONS
*
9.9
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
0010111010011101001010101110111100100010000101111010110
ANALOG
*
9.10
COMMUNICATION
CHANNELS
MEANS BY WHICH DATA ARE
TRANSMITTED:
• TWISTED WIRES (Copper Wires)
• COAXIAL CABLE: (Insulated Copper
Wires)
• FIBER-OPTIC CABLE
• MICROWAVE
*
9.11
FIBER OPTICS
• SUPER CLEAR GLASS STRANDS
• FAST, LIGHT, DURABLE
• UP TO TEN BILLION BITS PER SECOND,
FULL DUPLEX
• EXPENSIVE, HARDER TO INSTALL
• OFTEN USED AS BACKBONE OF
NETWORKS
PHOTO
*
SIGNAL
LASER
CABLE
SIGNAL
DETECTOR
9.12
LOW-ORBIT SATELLITE
MICROWAVE
TRANSMISSION
UPLINK
9.13
DOWNLINK
WIRELESS TRANSMISSION
TECHNOLOGIES
9.14
• 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
• SMART PHONE: Wireless, voice, text,
Internet
*
9.15
COMMUNICATIONS
CHANNELS
• TRANSMISSION SPEED: Bits per
Second (BPS) or Baud
• BANDWIDTH: Capacity of Channel;
Difference between Highest & Lowest
Frequencies
*
9.16
SPEEDS & COST OF MEDIA
MEDIUM
TWISTED WIRE
SPEED
300 BPS - 10 MBPS
MICROWAVE
256 KBPS - 100 MBPS
SATELLITE
256 KBPS - 100 MBPS
COAXIAL CABLE
56 KBPS - 200 MBPS
FIBER OPTICS
500 KBPS - 10 GBPS
BPS: BITS PER SECOND
KBPS: KILOBITS PER SECOND
MBPS: MEGABITS PER SECOND
GBPS: GIGABITS PER SECOND
9.17
COST
LOW
HIGH
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
*
9.18
NETWORK TOPOLOGIES
USER
USER
STAR
9.19
HOST
USER
USER
NETWORK TOPOLOGIES
BUS
9.20
USER
USER
USER
USER
USER
USER
NETWORK TOPOLOGIES
USER
USER
RING
9.21
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
*
9.22
LOCAL AREA NETWORK (LAN)
• SERVER: stores programs, data; determines
access to network
• GATEWAY: connection 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
*
9.23
WIDE - AREA NETWORK (WAN)
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
*
9.24
VALUE-ADDED
NETWORK (VAN)
•
•
•
•
9.25
PRIVATE; MULTIPATH; DATA ONLY
3rd PARTY MANAGED
USED BY SEVERAL ORGANIZATIONS
SUBSCRIPTION BASIS
*
NETWORK SERVICES
•
•
•
•
PACKET SWITCHING
FRAME RELAY
ASYNCHRONOUS TRANSFER MODE (ATM)
INTEGRATED SERVICES DIGITAL
NETWORK
• DIGITAL SUBSCRIBER LINE
• CABLE MODEM
• T1 LINE
*
9.26
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
*
9.27
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
*
9.28
INTEGRATED SERVICES
DIGITAL NETWORK (ISDN):
INTERNATIONAL STANDARD FOR
TRANSMITTING VOICE, VIDEO, DATA
OVER PUBLIC TELEPHONE LINES
*
9.29
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
9.30
*
ENTERPRISE NETWORK
• HARDWARE; SOFTWARE;
TELECOMMUNICATIONS, DATA
RESOURCES
• MORE COMPUTING POWER ON THE
DESKTOP
• NETWORK LINKING SMALLER
NETWORKS
*
9.31
INTERNETWORKING
LINK NETWORKS
EACH RETAINS IDENTITY
INTO INTERCONNECTED NETWORK
*
NETWORK
C
NETWORK
A
NETWORK
B
9.32
CONNECTIVITY
MEASURE OF ABILITY OF
COMPUTING DEVICES TO PASS &
SHARE INFORMATION WITHOUT
HUMAN INTERVENTION
OPEN SYSTEMS: Software Able to
Function on Different Computer
Platforms. Nonproprietary Operating
Systems, Applications, Protocols
*
9.33
TRANSMISSION CONTROL
PROTOCOL / INTERNET
PROTOCOL (TCP / IP)
REFERENCE MODEL DEVELOPED BY
DEPARTMENT OF DEFENSE IN 1972
1. APPLICATION: Provides Screen
Presentations
2. TRANSMISSION CONTROL PROTOCOL
(TCP): Breaks Data into Datagrams
3. INTERNET PROTOCOL (IP): Breaks,
Sends Datagrams as Smaller IP Packets;
Can Repeat Transmission to Increase
Reliability
9.34
*
TRANSMISSION CONTROL
PROTOCOL / INTERNET
PROTOCOL (TCP / IP)
4. NETWORK INTERFACE: Handles
Addressing and Interface Between
Computer & Network
5. PHYSICAL NET: Defines Electrical
Transmission Characteristics for Sending
Signal Along Networks to Destination
*
9.35
OPEN SYSTEM
INTERCONNECT (OSI)
INTERNATIONAL REFERENCE
MODEL
FOR LINKING DIFFERENT TYPES
OF
COMPUTERS & NETWORKS
*
9.36
FACILITATING
APPLICATIONS
•
•
•
•
•
•
•
9.37
ELECTRONIC MAIL (e-mail)
VOICE MAIL
FACSIMILE MACHINES (fax)
TELECONFERENCING
DATACONFERENCING
VIDEOCONFERENCING
GROUPWARE
*
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
9.38
ELECTRONIC DATA
INTERCHANGE (EDI)
COMPUTER - TO - COMPUTER
EXCHANGE BETWEEN TWO
ORGANIZATIONS
OF STANDARD BUSINESS
TRANSACTION DOCUMENTS
SELLER
CUSTOMER
*
ORDERS, PAYMENTS
COMPUTER
SHIPPING NOTICES, PRICE
UPDATES, INVOICES
9.39
COMPUTER
PROBLEMS POSED BY
ENTERPRISE NETWORKING
• CONNECTIVITY
• LOSS OF MANAGEMENT CONTROL
• ORGANIZATIONAL CHANGE
REQUIREMENTS
• HIDDEN COSTS OF CLIENT/SERVER
COMPUTING
• RELIABILITY & SECURITY
*
9.40
COSTS OF CLIENT/SERVER
SYSTEMS
• OPERATIONS & SUPPORT
• APPLICATION DEVELOPMENT
• HARDWARE, SOFTWARE, INSTALLATION,
MAINTENANCE
• EDUCATION &
TRAINING
*
9.41
TELECOMMUNICATIONS PLAN:
• KNOW LONG-RANGE PLANS
• AUDIT EXISTING CAPABILITIES
• IDENTIFY, PRIORITIZE CRITICAL
IMPROVEMENTS
• ENHANCE FIRM’S STRATEGIC POSITION
IMPLEMENT PLAN
*
9.42
IMPLEMENTATION FACTORS
•
•
•
•
•
•
•
•
9.43
DISTANCE
RANGE OF SERVICES
SECURITY
MULTIPLE ACCESS
UTILIZATION
COST
INSTALLATION
CONNECTIVITY
*
Connect to the INTERNET
PRESS LEFT MOUSE BUTTON ON ICON TO
CONNECT TO THE LAUDON & LAUDON
WEB SITE FOR MORE INFORMATION ON
THIS CHAPTER
9.44
9.45