CSMA (Carrier Sense Multiple Access): A MAC method of listening before transmitting (collision avoidance) and listening while transmitting (collision detection). For a wired network, such as Ethernet, collision detection is employed and packets are retransmitted should a collision be detected while transmitting. For wireless networks, this type of collision detection is usually not possible since the strength of a radio’s own transmissions would mask all other signals on the air. So for wireless networks, collision avoidance is employed.