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CSMA/CD or CSMA/CA for a wireless LAN

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4 replies

by h.sanber

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Why I cant use CSMA/CD for a wireless LAN.

4 replies

by spitfire_sysop

Why would you even want to if it were physically possible? (It's not). What are you trying to accomplish?

by sanjeeb69

CSMA/CD (Collision Detection) is the MAC method used in
a wired LAN (Ethernet). Wired LAN stations can (whereas
wireless stations cannot) detect collisions.

In case of WLAN, while transmitting, the strength of its own transmissions would mask all other signals on the air. So, the protocol can't directly detect collisions like with Ethernet and only tries to avoid them.

However, on a wire, the transceiver has the ability to listen while transmitting and so to detect collisions (with a wire all transmissions have approximately the same strength).

by robo_dev

is only effective if the client can communicate back to the sender to tell it to slow down or re-send the data. Since a WLAN typically has a much higher collision rate than a wired LAN, this would mean that the collision detection messages would not make it back to the sender. WLAN is a shared medium, so collision rates tend to be very high.

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