Which statement best differentiates bandwidth from throughput?

• A. Bandwidth is the maximum data rate of a link; Throughput is the actual data rate achieved.
• B. Bandwidth is the actual data rate achieved; Throughput is the maximum data rate.
• C. Bandwidth is the time delay; Throughput is the data rate.
• D. Bandwidth is the protocol overhead measure; Throughput is the link utilization.

Answer: (A)

Bandwidth is the maximum data rate a link can carry, i.e., its capacity. Throughput is the actual data rate that is successfully delivered over the link, which is the observed performance after accounting for overhead, errors, retransmissions, and other inefficiencies. In practice, throughput cannot exceed bandwidth, and it is often less due to protocol overhead (headers, framing), network congestion, and delays. So the best statement is the one that describes bandwidth as the link’s maximum capacity and throughput as the real data rate achieved.