Transcript Chap9

9.1
LEARNING OBJECTIVES
• COMPARE TYPES OF
NETWORKS & NETWORK
SERVICES
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9.2
LEARNING OBJECTIVES
• DESCRIBE CONNECTIVITY
NETWORK STANDARDS
• IDENTIFY APPLICATIONS FOR
SUPPORTING ELECTRONIC
COMMERCE, BUSINESS
• ANALYZE MANAGEMENT
PROBLEMS OF
NETWORKING
9.3
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MANAGEMENT CHALLENGES
• TELECOMMUNICATIONS REVOLUTION
• COMPONENTS, FUNCTIONS OF
TELECOMMUNICATIONS SYSTEM
• COMMUNICATIONS NETWORKS
• ELECTRONIC COMMERCE, ELECTRONIC
BUSINESS TECHNOLOGIES
• MANAGEMENT ISSUES, DECISIONS
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9.4
PROTOCOL
RULES & PROCEDURES
TO GOVERN TRANSMISSION
BETWEEN COMPONENTS
IN A NETWORK
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9.8
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
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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
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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
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9.24
VALUE-ADDED
NETWORK (VAN)
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9.25
PRIVATE; MULTIPATH; DATA ONLY
3rd PARTY MANAGED
USED BY SEVERAL ORGANIZATIONS
SUBSCRIPTION BASIS
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NETWORK SERVICES
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PACKET SWITCHING
FRAME RELAY
ASYNCHRONOUS TRANSFER MODE (ATM)
INTEGRATED SERVICES DIGITAL
NETWORK
• DIGITAL SUBSCRIBER LINE
• CABLE MODEM
• T1 LINE
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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
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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
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9.28
INTEGRATED SERVICES
DIGITAL NETWORK (ISDN):
INTERNATIONAL STANDARD FOR
TRANSMITTING VOICE, VIDEO, DATA
OVER PUBLIC TELEPHONE LINES
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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
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ENTERPRISE NETWORK
• HARDWARE; SOFTWARE;
TELECOMMUNICATIONS, DATA
RESOURCES
• MORE COMPUTING POWER ON THE
DESKTOP
• NETWORK LINKING SMALLER
NETWORKS
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9.31
INTERNETWORKING
LINK NETWORKS
EACH RETAINS IDENTITY
INTO INTERCONNECTED NETWORK
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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
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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
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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
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9.35
OPEN SYSTEM
INTERCONNECT (OSI)
INTERNATIONAL REFERENCE
MODEL
FOR LINKING DIFFERENT TYPES
OF
COMPUTERS & NETWORKS
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9.36
FACILITATING
APPLICATIONS
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9.37
ELECTRONIC MAIL (e-mail)
VOICE MAIL
FACSIMILE MACHINES (fax)
TELECONFERENCING
DATACONFERENCING
VIDEOCONFERENCING
GROUPWARE
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ELECTRONIC DATA
INTERCHANGE (EDI)
COMPUTER - TO - COMPUTER
EXCHANGE BETWEEN TWO
ORGANIZATIONS
OF STANDARD BUSINESS
TRANSACTION DOCUMENTS
SELLER
CUSTOMER
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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
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9.40
COSTS OF CLIENT/SERVER
SYSTEMS
• OPERATIONS & SUPPORT
• APPLICATION DEVELOPMENT
• HARDWARE, SOFTWARE, INSTALLATION,
MAINTENANCE
• EDUCATION &
TRAINING
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9.41
TELECOMMUNICATIONS PLAN:
• KNOW LONG-RANGE PLANS
• AUDIT EXISTING CAPABILITIES
• IDENTIFY, PRIORITIZE CRITICAL
IMPROVEMENTS
• ENHANCE FIRM’S STRATEGIC POSITION
IMPLEMENT PLAN
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9.42
IMPLEMENTATION FACTORS
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9.43
DISTANCE
RANGE OF SERVICES
SECURITY
MULTIPLE ACCESS
UTILIZATION
COST
INSTALLATION
CONNECTIVITY
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