Carrier-sense multiple access with collision detection

When two stations sense the channel to be idle and start transmitting simultaneously, they will both detect collision immediately. rather than finish transmitting their frame, that are irretrievably garbled anyway,they should abruptly stop transmitting as soon as the collision is detected. quickly terminating damaged frames saves time and bandwidth. This protocol is known as CSMA\CD.

This is widely used on LANs in the MAC sublayer.