CSMA/CD is an algorithm for transmission where each node listens to the medium to check if the medium is idle. Once it is detected that the medium is idle, the node begins transmission. However, if during transmission the node detects a collision, the node sends a jam signal that notifies other nodes of the collision. Transmission is paused, and the node again listens to continue transmission. After a random period of several attempts, the node can abort the transmission and begin afresh. CSMA/CA is also an algorithm that allows nodes to avoid collisions by listening to confirm when the medium is idle. Once the medium is idle, the node can begin the transmission of data.
CSMA/CA is an algorithm that is used to reduce the probability of collision along with a transmission medium. The algorithm requires that each node listens for a specified period to ascertain that the medium is idle. Once it is confirmed, the node can begin to transmit data over the channel. In Wi-Fi applications, CSMA/CD is not used, and the more common approach is the use of CSMA/CA or another algorithm. The reason for this is that owing to the nature of the medium. It is not possible to listen while sending, as in the case of wired networks. On a wired network, it is possible to measure signal strength to detect collision. However, in Wi-Fi that uses radio waves, it is not possible to measure this hence the application of an avoidance scheme as opposed to a detection scheme.