Carrier Sense

Devices based on the 802.3 and 802.11 standards must use the carrier sense multiple access (CSMA) technique to determine if the media is available before transmitting. Wired devices are able to sense an electrical signal on the wire to detect a transmission already in progress. Wireless devices can use a two-fold process to detect a channel in use:

Image Physical Carrier Sense—When a wireless client is not transmitting, it can listen to the channel to overhear any other transmissions that might be occurring. If it overhears a frame that is destined for its own MAC address, then it receives the frame for processing. Otherwise, if a transmission ...

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