If you are not too aware of what CSMA/CD is, this is a media control method. This is known to be one of the early methods that are used in order to do networking.
It will defer the other transmissions until such time when there will not be any stations that will provide other distracting transmissions. When a collision occurs, all of the other frames will be discarded. For example, if there is a LAN that comes with a lot of hosts, this might become a problem without the right CSMA/CD to keep track of everything.
A device listens and waits until the media is not busy before transmitting. All of the devices on a segment see data that passes on the network medium. After detecting a collision, hosts can attempt to resume transmission after a random time delay has expired.