Carrier Sense Multiple Access(CSMA) In certain situations nodes can hear each other by listening to the channel “Carrier Sensing CSMA: Polite version of Aloha Nodes listen to the channel before they start transmission Channel idle=> Transmit Channel busy = Wait (join backlog) When do backlogged nodes transmit? When channel becomes idle backlogged nodes attempt transmission with probability q=1 Persistent protocol, q=1 Non-persistent protocol,< 1