COMMUNICATIONS AND NETWORKS

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COMMUNICATIONS AND NETWORKS
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Competencies

• Discuss connectivity, the wireless revolution,
  and communication systems
• Describe physical and wireless communications
  channels
• Discuss connection devices
• Describe data transmission factors

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Competencies cont.

• Discuss networks and key network terminology
• Describe the different types of networks
• Describe network architectures
• Describe organizational uses of Internet
  technologies

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What is Communication?
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Communications Today
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Communication Systems
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Communication Channels

• Channels carry data from one computer to another
• Two categories of communication channels
• Physical connection
• Wireless connection

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Physical Connections

• Telephone lines
• Coaxial cable
• Fiber-optic cable

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Wireless Connections

• Infrared
• Broadcast radio
• Microwave
• Stations
• Bluetooth
• Satellite
• Uplink/Downlink
• Global Positioning System

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More on Satellites

• Global positioning
• Network of 24 satellites
• Owned by the Defense Department
• Global positioning system (GPS)
• Devices used to determine location
• Provides navigational support

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Connection Devices

• Types of signals
• Analog
• Digital
• Types of modems
• Internal
• External
• PC Card
• Wireless

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Types of Connections

• Digital subscriber line (DSL)
• Uses existing phone lines
• ADSL (Asymmetric digital subscriber line)
• Cable modems
• Uses existing TV cable
• Provides speeds as fast as DSL at a lower cost
• Satellite/air connection services
• Seven times faster than dial-up
• Slower than DSL cable modem

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User Connection Costs Speeds
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Bandwidth

• Measurement of the capacity of the channel
• Categories
• Low bandwidths or Voiceband
• Medium band
• Broadband
• Used for high capacity transmission
• Used by DSL, cable satellite

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Protocols

• Set of communication rules
• Standard for Internet TCP/IP
• Transmission control protocol/Internet protocol
• Identifies devices
• Reformats information

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Networks

• A computer network is a communication system
• Connects two or more computers
• Allows information exchange

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Network Terms

• Node
• Client
• Server
• Hub
• Network interface cards (NIC)

• Network operating system (NOS)
• Distributed processing
• Host computer
• Network manager

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Network Types

• Local area networks
• Home networks
• Metropolitan
  area networks
• Wide area networks

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Network Architecture

• Architecture describes how a network is arranged
• Arrangement is called topology
• Types of network topology
• Star
• Bus
• Ring
• Hierarchical

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Star Network

• Smaller computers linked to a central unit
• Central unit is called the network hub
• Control is maintained by polling

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Bus Network

• Each device handles its own communication control
• There is no host computer
• Has a common connecting cable called a backbone

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Ring Network

• Each device is connected to two other devices
• No central file server or computer
• Useful in a decentralized environment

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Hierarchical Network

• Several computers linked to a central host
• Computers are hosts to other computers
• Useful in centralized organizations

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Strategies

• Strategy is a way of coordinating the sharing of
  information and resources
• Common network strategies
• Terminal
• Client/server
• Peer-to-peer

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Organizational Internets
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Internets and Extranets

• Intranets
• Private network within an organization
• Provides information to employees
• Extranets
• Private network that connects organizations
• Used to allow suppliers and others access
• Firewalls
• Security system
• Protects against external threats

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A Look to the FutureWireless Robotic Car

• Pod car (Personalization on Demand)
• Predicts and responds
• Designed to learn and adapt to an individual's
  driving needs and habits

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FAQs

• What is fiber-optic cable?
• My Palm Pilot uses Bluetooth. What is it?
• What is a modem?
• What is DSL? How does it work?
• How fast is broadband bandwidth?
• What is a local area network?
• What is meant by peer-to-peer?

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Discussion Questions

• Discuss what is meant by the wireless revolution.
• Discuss the four types of service connections.
• Discuss the advantages and disadvantages of the
  four network topologies.
• Explain the connections in a home network.
• Describe the different network topologies.
• Describe a GPS system.