9. TELECOMMUNICATIONS

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9. TELECOMMUNICATIONS AND NETWORKS
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LEARNING OBJECTIVES

• DESCRIBE COMPONENTS OF TELECOMMUNICATIONS SYSTEM
• CALCULATE CAPACITY OF TELECOMMUNICATIONS CHANNELS
  EVALUATE TRANSMISSION MEDIA
• COMPARE TYPES OF NETWORKS

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TELECOMMUNICATIONS

• COMMUNICATING INFORMATION
• VIA ELECTRONIC MEANS
• OVER SOME DISTANCE

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INFORMATION SUPERHIGHWAY

• NATIONAL / WORLDWIDE
• HIGH SPEED
• DIGITAL TELECOMMUNICATIONS
• ACCESSIBLE BY GENERAL PUBLIC

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SYSTEM COMPONENTS

• COMPUTERS
• TERMINALS (Input / Output Devices)
• COMMUNICATIONS CHANNELS
• PROCESSORS (Modems Multiplexers Front-end
  Processors)
• COMMUNICATIONS SOFTWARE

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PROTOCOL

• RULES PROCEDURES
• TO GOVERN TRANSMISSION
• BETWEEN COMPONENTS
• IN A NETWORK
• (ALLOWS COMPONENTS
• IN A NETWORK TO TALK
• TO EACH OTHER)

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ANALOG SIGNAL

• A CONTINUOUS WAVEFORM THAT PASSES THROUGH A
  COMMUNICATIONS MEDIUM USED FOR 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

00101110100111010010101011101111001000100001011110
10110
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COMMUNICATION CHANNELS

• MEANS BY WHICH DATA ARE TRANSMITTED
• TWISTED WIRES (Copper Wires)
• COAXIAL CABLE (Insulated Copper Wires)
• FIBER-OPTIC CABLE
• WIRELESS

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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 (MAJOR
  TRAFFIC)

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LOW-ORBIT SATELLITE
MICROWAVE TRANSMISSION
UPLINK
DOWNLINK
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WIRELESS TRANSMISSION TECHNOLOGIES

• PAGING SYSTEM 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

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COMMUNICATIONS CHANNELS

• TRANSMISSION SPEED Bits per Second (bps) Baud
• BANDWIDTH Capacity of Channel Difference
  between Highest Lowest Frequencies

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SPEEDS COST OF MEDIA
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NETWORK TOPOLOGIES
STAR
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NETWORK TOPOLOGIES
BUS
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NETWORK TOPOLOGIES
RING
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LOCAL NETWORKS

• PRIVATE BRANCH EXCHANGE (PBX) special-purpose
  computer designed for handling and switching
  office telephone calls at a company site
• 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)

• SERVER stores programs, data determines access
  to network
• GATEWAY connection to other dissimilar networks
• ROUTER route data through several connected LANs
  or to a WAN
• 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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ELEMENTS OF A BASIC LAN

• SERVER
• CABLING
• NETWORK INTERFACE CARDS (NICs)
• SOFTWARE (network operating system) FOR CLIENTS,
  SERVERS OR PEERS

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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 (typically a flat rate is
  paid for total access to the line)

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ENTERPRISE NETWORKING

• ORGANIZATIONS HARDWARE, SOFTWARE,
  TELECOMMUNICATIONS AND DATA RESOURCES ARE
  ARRANGED TO PUT MORE COMPUTING POWER ON THE
  DESKTOP AND TO CREATE A COMPANYWIDE NETWORK
  LINKING MANY SMALLER NETWORKS

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INTERNETWORKING

• LINKING OF SEPARATE NETWORKS, EACH OF WHICH
  RETAINS ITS OWN IDENTITY, INTO AN INTERCONNECTED
  NETWORK

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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 (e.g.
  Java)

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PROBLEMS POSED BY ENTERPRISE NETWORKING

• CONNECTIVITY
• LOSS OF MANAGEMENT CONTROL
• ORGANIZATIONAL CHANGE REQUIREMENTS
• HIDDEN COSTS OF CLIENT/SERVER COMPUTING
• NETWORK RELIABILITY SECURITY

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COSTS OF CLIENT/SERVER SYSTEMS

• OPERATIONS SUPPORT
• APPLICATION DEVELOPMENT
• HARDWARE, SOFTWARE, INSTALLATION AND MAINTENANCE
• EDUCATION TRAINING

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SOME SOLUTIONS TO PROBLEMS

• Managing the change
• Education and training
• Data administration disciplines (accurateness,
  data available only to authorized users and
  properly backed up)
• Planning for connectivity

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9. TELECOMMUNICATIONS AND NETWORKS
9.45