Information Systems Today: Managing in the Digital World TB4-1
4Technology Briefing
Networking
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Learning Objectives
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Learning Objectives
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Evolution of Computer Networking• Computer networking
o Sharing of information or services
o Comparable to human communication
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Messages, Senders, and Receivers• Components of communication:
o Senders and receivers with something to share
o A transmission medium to send the message
o Protocols (rules) dictating communication
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Coding, Sending, Decoding
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Computer Networks• Computer communication
o Bits are sent
o Any type of information can be transmitted
• Documents, art, music, film, information
• Digitizingo Conversion of
analog into digital information
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Bandwidth Requirements
• Voiceo Telephone: 64 KBps
o Compact Disc: 1.41 MBps
• Datao Single screen of text: 14.4 KB
o Publication-quality photograph: 230.4 MB
• Videoo Video telephony: 9.3 MBps
o HDTV: 1.33 GBps
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Centralized Computing• 1940s – 1970s (mainframe era)
• Central computer (mainframe)o Processing and
storage of data
• Terminalo Local input/output
device
• Not a true network – no information sharing
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Distributed Computing• 1980s
• Driver: Introduction of PCs
• Separate computers work on subsets of tasks
• Results are pooled via network
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Collaborative Computing• 1990s
• Synergistic form of distributed computing
• Two or more computers working on a common processing tasko Computers collaborate to keep employee records current
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Collaborative Computing
• Collaborative functionality in IM platforms
• Collaborative components in office automation applications
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Computing Networks Today• All types are still present
o (centralized, distributed, collaborative)
• Usually combined into a networko Networks classified by size, distance
covered and structure:•Private branch exchange
•Local area network
•Wide area network
•Metropolitan area network
•Personal area network
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Private Branch Exchange
• Telephone system serving a particular locationo Connects phones
and computers
o Connects PBX to outside network
• Limited bandwidth
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Local Area Network• Spans relatively small area – tens of kilometers
• Computers share:o Information o Peripheral devices
• Wireless Local Area Network (WLAN)
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Wide Area Network
• Spans relatively large areao Usually connects multiple LANs
• Used by multinational companies
• Information transmitted across cities and countries
• 4 specific types of WAN
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Global and Enterprise Networks
• Global networkso Span multiple
countrieso E.g., The Internet
• Enterprise networkso Connect disparate
networks of a single organization
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Value-Added and Metropolitan Area Networks
• Value-added networkso Medium speed WANso Third party managedo Shared by multiple organizationso Added value:
• network management, e-mail, EDI, security
• Metropolitan area networkso Limited geographic scope – citywide area
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Personal Area Networks
• Exchange data between computing devices
• Short range radio communication – 10 meterso E.g., networking of PCs,
peripheral devices, mobile phones, portable stereos, etc.
• Enabling Technology: Bluetooth
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Learning Objectives
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Transmission Media• Physical pathways for sending data
• Two types:o Cable media
o Wireless media
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Networking Fundamentals
• Three different roles:o Servers
o Clients
o Peers
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Servers
• Only provide services
• Usually have:o More advanced
microprocessorso More memory
• Many users share services
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Clients
• Request services
• Workstations or PCs
• Software applications
• Usually one user per client
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Peers
• May request and provide services
• Peer-to-peer networkso Equivalent capabilities and
responsibilities
• Usually found in small offices and homes
• Popular for file sharingo E.g., BitTorrent, KaZaA
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Network Services
• File serviceso Store, retrieve
and move data files
• Print serviceso Control and
manage access to printers
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Network Services (II)• Message services
o Store, access and deliver data
o Communication between users and applications
• Application Serviceso Run software for network
clients
o Enable computers to share processing power
o Client/server computing
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Network Operating System (NOS)• System software controlling the network
• Enables computers to communicate
• Two parts:o Network server
• Coordinates: user accounts, information access, security, resource sharing
o Workstation
• Runs on top of the local OS
• Sometimes integrated into the OS
• Example: Novell NetWare, Microsoft Windows Server