CSMA

• “Sense the carrier” (radio lingo) before transmitting

• 1-persistent CSMA: If the channel is idle, transmitIf the channel is busy, wait until idle and transmit

• 0-persistent CSMA: If the channel is busy, go away for a random period of time

• p-persistent CSMA: Applies to slotted channels.

  • If the channel is busy, wait until next slot.
  • If the channel is idle, transmit with a probability p or wait until next slot with probability 1-p
  • Slot length = propagation delay

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