A condition that occurs when two or more stations on a network try to access the network media simultaneously. In other words, the stations are contending for control of the media.
There are different ways of resolving contention issues on a network. One way is to use a single station as the master or primary station that controls all communication on the network. Other devices on the network function as slave, or secondary, stations. The entire system is known as a master-slave system. The master station normally functions in transmit mode, while the slave stations operate in receive mode.
The master station tells individual slave stations when they should switch to transmit mode in order to transmit information over the network. This kind of scenario is used in networks based on IBM’s Systems Network Architecture (SNA).
In Ethernet networks, the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) method is used to resolve contention on the network by allowing collisions to occur, and then resolving them successfully.