[Bloat] BBR high RTT unfairness: Fifty Shades of Congestion Control: A Performance and Interactions Evaluation

[Dave Taht]

I have been trying to work through this paper:
https://arxiv.org/pdf/1903.03852.pdf
which is enormous and well worth reading.

I have a theory, though, about TABLE XII, which contrasts four BBR
flows at different RTTs, in that BBRv1's probe phase makes a 200ms
assumption, thus
not seeing the real rtt at ong rtts, and thus the longest RTT flow
gets the most bandwidth on this test, and the second (testable) theory
is that were these rtts not exactly on the 100ms boundaries, we  would
see more throughput fairness.

and thus we end up with the
                      tput
BBR(100ms) 0.94 95.90 1.02 1.02 0.62
BBR(200ms) 2.36 95.89 2.53 2.48
BBR(300ms) 1.09 95.89 1.20 1.14
BBR(400ms) 4.57 95.89 4.79 4.59

-- 

Dave Täht
CTO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-831-205-9740