Re: [aqm] [Bloat] TCP BBR paper is now generally available

Aaron Wood <> Fri, 02 December 2016 19:15 UTC

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From: Aaron Wood <>
Date: Fri, 2 Dec 2016 11:15:41 -0800
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To: Dave Taht <>
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Subject: Re: [aqm] [Bloat] TCP BBR paper is now generally available
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This is really fascinating reading.

The following made me stop for a second, though:

"The bucket is typically full at connection startup so BBR learns the
underlying network's BtlBw, but once the bucket empties, all packets sent
faster than the (much lower than BtlBw) bucket fill rate are dropped. BBR
eventually learns this new delivery rate, but the ProbeBW gain cycle
results in continuous moderate losses. To minimize the upstream bandwidth
waste and application latency increase from these losses, we added policer
detection and an explicit policer model to BBR."

So, how is this likely to be playing with our qos_scripts and with cake?

Given we have people from both Google and qos_scripts/cake development
here, do we need to compare some notes on how these interact?  Are there
settings in the HTB setup used by qos_scripts that will make it play more
nicely with BBR (smaller quantums, smaller burst sizes, etc)?


On Fri, Dec 2, 2016 at 7:52 AM, Dave Taht <> wrote:

> --
> Dave Täht
> Let's go make home routers and wifi faster! With better software!
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