Question

Consider an Ethernet segment with a transmission speed of 10^8 bits/sec and a maximum segment length of 500 meters. If the speed of propagation of the signal in the medium is 2×10^8 meters/sec, then the minimum frame size (in bits) required for collision detection is ____.

Accepted Answer

The correct answer is 500 bits. Propagation delay = 500m / (2×10^8 m/s) = 2.5 μs. For collision detection, transmission time must be at least the round-trip propagation delay: 2×2.5 = 5 μs. Minimum frame size = transmission rate × time = 10^8 bits/sec × 5×10^-6 s = 500 bits.

Explanation