Why do collisions reduce network performance?

Why do collisions reduce network performance?

• A. Because the signal is encrypted
• B. Because the signal must be retransmitted
• C. Because bandwidth doubles after collision
• D. Because devices switch channels

Answer: (B)

Collisions waste time on a shared network medium. When two or more devices transmit at the same moment, their signals interfere and the frames get garbled. The network protocol detects the collision and must retry sending the frames. That retry process uses additional time and consumes bandwidth without delivering useful data, which lowers the effective throughput. Saying the signal must be retransmitted captures this core effect: the original transmission fails due to the collision, so the data must be sent again, adding overhead and slowing down overall performance. The other options aren’t accurate explanations: encryption isn’t related to collisions; bandwidth doesn’t magically double after a collision (it remains the same but with wasted time); and devices don’t typically switch channels to resolve a collision on a shared Ethernet.

Collisions waste time on a shared network medium. When two or more devices transmit at the same moment, their signals interfere and the frames get garbled. The network protocol detects the collision and must retry sending the frames. That retry process uses additional time and consumes bandwidth without delivering useful data, which lowers the effective throughput.

Saying the signal must be retransmitted captures this core effect: the original transmission fails due to the collision, so the data must be sent again, adding overhead and slowing down overall performance. The other options aren’t accurate explanations: encryption isn’t related to collisions; bandwidth doesn’t magically double after a collision (it remains the same but with wasted time); and devices don’t typically switch channels to resolve a collision on a shared Ethernet.