Work out tcp throughput from latency instantly with clear inputs, formula shown and shareable results.
A single TCP stream can have at most one window of data outstanding per round trip, so throughput is window divided by RTT. Loss imposes a second ceiling described by the Mathis formula, MSS x 1.22 / (RTT x sqrt(loss)), because congestion control halves the window on every loss event. On long fat links, either constraint can dominate.
TCP throughput limits
window limit = window bytes x 8 / RTT; loss limit = MSS x 8 x 1.22 / (RTT x sqrt(loss)); actual = the lower of the two
Because window over RTT caps it. A 256 KB window over an 80 ms path yields about 26 Mbps regardless of the link being 10 Gbps — window scaling or parallel streams are required.
Yes. BBR models bandwidth and RTT rather than treating loss as congestion, so it sustains much higher rates on lossy long paths than loss-based algorithms like CUBIC.