• In this scheme, if a station wants to transmit a frame and it finds that the channel is busy (some other station is transmitting) then it will wait for fixed interval oftime.
• After this time, it again checks the status of the channel and if the channel is.free it will transmit.
• A station that has a frame to send senses the channel.
• If the channel is idle, it sends immediately.
• If the channel is busy, it waits a random amount of time and then senses the channel again.
• In non-persistent CSMA the station does not continuously sense the channel for the purpose of capturing it when it detects the end of previous transmission.
Advantage of non-persistent
• It reduces the chance of collision because the stations wait a random amount of time. It is unlikely that two or more stations will wait for same amount of time and will retransmit at the same time.
Disadvantage of non-persistent
• It reduces the efficiency of network because the channel remains idle when there may be stations with frames to send. This is due to the fact that the stations wait a random amount of time after the collision.