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CSMA/CD - technical definition

The most common medium access control (MAC) protocol used in bus networks, including 802.3 (Ethernet). The transmitting Ethernet station sends a data frame in both directions of the bus. Each transceiver of each station in the path of the frame reads the address in the frame header. If the address matches, the transceiver provides the frame to the target device. If the address does not match, the transceiver forwards the frame to the next transceiver. If any node detects a data collision, that station sends a brief jamming signal over a subcarrier frequency to advise all stations of the collision. All devices then back off the network. If the network is running the Nonpersistent CSMA protocol, each station then calculates a random time interval before monitoring the network again, and attempting a retransmission. See also 802.3, bus, CSMA, CSMA/CA, Ethernet, frame, MAC, Nonpersistent CSMA, subcarrier, and transceiver.

See CSMA/CD in Computer

(Carrier Sense Multiple Access/Collision Detection) The LAN access method used in Ethernet. When a device wants to gain access to the network, it checks to see if the network is quiet (senses the carrier). If it is not, it waits a random amount of time before retrying. If the network is quiet and two devices access the line at exactly the same time, their signals collide. When the collision is detected, they both back off and each wait a random amount of time before retrying. See CSMA/CA and Ethernet.

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CSMA/CD - technical definition

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