Is it really necessary to go beyond a fairness metric for next-generation congestion control?

A recent article suggests that the potential for deployment of congestion control mechanisms in the future Internet should be evaluated using a new concept called "harm" instead of measuring "fairness". While there are good arguments in favor of this new approach, its practical benefits have not yet been experimentally evaluated, and calculating harm requires producing more experimental data. We apply the harm concept to data produced in real-life experiments with competing pairs of various TCP variants: Cubic vs. Reno, BBR vs. Cubic, and Reno vs. Vegas. These experiments cover various levels of "aggression" as well as different feedback types that the controls are based upon. We present a new linear representation of relative harm between scenarios, which can help us to assess the differences in harm between a variety of situations. Among other results, we can see that BBR is on average 1.6 times more harmful to Cubic in high-BDP situations (when Cubic is most aggressive) than Cubic is to Reno.