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Transcript

  • 1. Networking BASICS
    • Network Media
    • Unit 1
    • Lesson 2
  • 2. Types of Networks
    • There are two types of networks by which information is transmitted:
      • circuit switched networks
      • packet switched networks
  • 3. Circuit Switched Network
    • There is a dedicated and direct physical connection between sender and receiver.
    • No other transmissions can take place while the connection is active.
    • Once the transmission is ended, other connections can be made with other devices.
    • It is ideal for voice communications because there are no interruptions from other devices or delays.
  • 4. Packet Switched Network
    • This network requires data transmission be broken into smaller units called packets .
    • Each packet is sent independently through the network.
    • It is used for data transmission because data is not as time-sensitive as voice communication.
    • It allows multiple devices to share one line or frequency.
    • It facilitates error correction.
  • 5. Signaling Techniques
    • There are two ways that a signal is sent across a network medium:
      • baseband signaling
      • broadband signaling
  • 6. Baseband Signaling
    • Sends one data signal across the network media
    • Entire capacity of the media is used for the one data signal
    • Signals are transmitted in a digital format
    • Many devices can send and receive across the medium, but only one at a time
  • 7. Baseband Signaling
  • 8. Broadband Signaling
    • Divides the cable into several different channels
    • Signals are transmitted at different frequencies in an analog mode
    • Allows many different signals to be sent simultaneously on a single cable
    • Signal sent in only one direction
    • Used for computer network data transmissions
  • 9. Broadband Signaling
  • 10. Factors Affecting Transmissions
    • The flow of a signal down the network media can become distorted.
    • Common types of distortions are attenuation and interference.
  • 11. Attenuation
    • Loss of signal power
    • Measured by the decrease in decibels (db) over a specific distance
  • 12. Interference
    • Interference is caused when a strong external signal interferes with a signal.
    • Radio frequency interference (RFI) - interference caused by broadcast signals from a radio or television transmitter.
    • Electromagnetic interference (EMI) - motor or source of intense electrical activity creates an electromagnetic signal that interferes with a data signal.
    • Near end crosstalk (NEXT) and Far end crosstalk (FEXT) - interference from another data signal being transmitted on adjacent wire.
  • 13. Transmission Media
    • Copper cables
    • Fiber optic cables
    • Wireless
  • 14. Copper Cables
    • Thin coaxial
    • Shielded twisted pair (STP)
    • Unshielded twisted pair (UTP)
    • UTP rated by Category 1 - 6
  • 15. Copper Cables
  • 16. Copper Cables
  • 17. Fiber Optic
    • This cable uses a thin cylinder of glass to send light impulses.
    • The cable consists of a strand of glass ( core) surrounded by a glass tube ( cladding ).
    • Single mode - one light source flashes a light down the cable.
    • Multimode - supports many simultaneous light transmissions.
  • 18. Fiber Optic
  • 19. Wireless
    • Transmission is sent and received through invisible waves
    • Less expensive than copper or fiber optic lines.
    • Allows the user to move freely around the office or campus and still remain connected to the network
    • Fastest-growing segment of network media today
  • 20. Wireless Transmissions
    • Infrared transmits data using infrared (IR) light.
    • IR shares many of the same properties as visible light .
    • Radio frequency signals can be transmitted over radio waves similar to local radio station transmissions.
    • The signal comes in at a lower power level and does not reach as far.
  • 21. Network Interface Card
    • The NIC serves as the connection between the personal computer and the network media.
    • It connects to the computer on its base by plugging into an expansion slot of the computer.
    • Another connection is accessible from the outside of the computer and has connections for the cables to plug into the network.
  • 22. Network Interface Card
    • Changes from parallel to serial transmission
    • Creates packets
    • Determines when to send
    • Transmits packet
  • 23. Network Interface Card