How do SFP and QSFP transceivers differ in terms of data-rate capabilities?

• A. SFPs typically support up to ~1 Gbps; QSFPs support higher rates (e.g., 4x1G, 40G)
• B. SFPs are faster than QSFPs
• C. SFPs are fiber optic transmitters; QSFPs are copper only
• D. SFPs support only 10G; QSFP supports 100G

Answer: (A)

The key idea is how many lanes the module uses and how fast each lane can run. An SFP module carries a single data channel, so its typical data rate is around 1 Gbps. A QSFP module bundles four lanes in one package, so it can deliver much higher total throughput by aggregating those lanes. For example, four lanes at 10 Gbps each give 40 Gbps, which is a common QSFP rate. In newer versions, four lanes at 25 Gbps each push the total toward 100 Gbps. So, SFPs are limited to lower, single-lane speeds, while QSFPs combine several lanes to achieve significantly higher data rates.