Carrier Sense Multiple Access / Collision Detection -- a set of rules that determine how network devices respond when two devices attempt to use a data channel simultaneously (called a collision). Standard Ethernet networks use CSMA/CD.

The standard enables devices to detect a collision. After detecting a collision, a device delays trying to access the cable again for a random delay time. If the device detects a collision again, it waits up to twice as long to try to re-transmit the message.