Questions and Answers

  • Network: A set of devices connected by a physical medium, where we can cal each device as a node.
  • Link: The physical medium of connection is called as a link.
  • Communication Networks
    • Simplex: The sender sends and the receiver receives. Eg: Radio
    • Half-Duplex: When the sender is sending the listener receives but cannot send at the time when the sender is transmitting data. Once the sender is done the receiver can transmit the data. Eg: walkie-talkie
    • Full-Duplex: Eg: Telephone call
  • Explain Unicasting, Anycasting, Multicasting and Broadcasting.
    • Unicasting: Sending to only one address.
    • Anycasting: Message is sent from the source to any specific node.
    • Multicasting: Sending the message to group of subset of people
    • Broadcasting: Sending the messages to everyone(used by DHCP and ARP)
  • Explain the types of networks based on different categories
    • Transmission media:
      • Twisted Pair: Contains two pairs. It is twisted to reduce the signal attenuation that is caused by the electromagnetic waves. There are basically two types
        • UTP: These are the normal ethernet cables we use. Usually just wrapped in a plastic cover. There can be disturbances in the signals.
        • STP: It doesn't have any disturbances in the symbol. Applications: Medical connection(remember about disturbances and what happens in Medical Applications)s
      • Co-axial: Contains four pairs. Used in TV cables. They are of two types
        • Thick net
        • Thin net
      • Fibre Optics: Works on the idea of the critical angle that causes the total internal reflection. The light/signal is made to reflect in an angle more than the critical angle and henceforth cause internal reflection and then the data can be transferred very fast.