[Bloat] Fair queuing detection for congestion control

[Sebastian Moeller]

Hi Maximilian,

I read the following:
"D. Other variants of fair queuing

We also evaluated the performance of our fair queuing detection on a bottleneck managed by fq codel [5]. We chose a default target queuing delay of 10ms following Apple’s implementation3 because we argue that Apple probably spent a considerable amount of time fine-tuning their implementation and came to the conclusion that 10 ms work best as the default target delay."


And wonder whether you could:
a) repeat that experiment with fq_codel's defaults of 100ms interval and 5ms target using the Linux implementation. I am not saying Apple might not have a decent rationale for their choice, but as far as I can tell they have not communicated that rationale. The Linux defaults however are explained relatively well in e.g. fq_codel's IETF RFC.
b) produce some CDF plots that show the detection accuracy for the different RTTs and rates (you can probably combine either all RTTs or al rates into one plot)
c) maybe use signal detection theory terms to show the performance in terms that include false positive and false negative classifications?

Regards
	Sebastian


> On Jun 27, 2022, at 18:23, Maximilian Bachl via Bloat <bloat at lists.bufferbloat.net> wrote:
> 
> This paper (pre-print) 
> https://arxiv.org/abs/2206.10561 proposes a mechanism to monitor the presence of FQ continuously during a flow’s lifetime. This can be used to change the congestion control depending on the presence of FQ.
> 
> Furthermore, the paper argues that the presence of FQ can be considered a congestion signal: Only if there’s congestion, FQ can be detected. 
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