The CSMA/CD algorithm mitigated this problem significantly.
Briefly, using the CSMA/CD approach, when a computer on a LAN wants to transmit,
it listens to the cable (i.e., ???senses??? the cable); if the cable is busy, the computer waits
until it goes idle; otherwise, it transmits immediately. If other computers on the
cable simultaneously begin transmission as well (since they all sensed the cable was
idle), collisions will occur. When a computer detects a collision, it stops transmission
immediately for a random amount of time, after which it starts the process of listening
to the cable again. The amount of time that a computer waits before listening again is
determined by a ???binary exponential backoff??? algorithm, which dynamically adjusts the
random interval before which a computer can attempt to retransmit. When two colliding
computers back off using this algorithm, the chance of their respective transmissions
colliding yet again when they both attempt to retransmit is negligible.20 If a collision
reoccurs, however, then a new backoff time is computed before a retransmission attempt
is scheduled, so the possibility of colliding on this second retransmission is reduced
exponentially again.
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