[Cerowrt-devel] Comcast's NANOG slides re Bufferbloat posted (Oct 2016)

[Dave Taht]

On Thu, Oct 20, 2016 at 11:12 AM, Mikael Abrahamsson <swmike at swm.pp.se> wrote:
> On Thu, 20 Oct 2016, Rich Brown wrote:
>
>>
>> https://www.nanog.org/sites/default/files/20160922_Klatsky_First_Steps_In_v1.pdf
>
>
> Does anyone understand what access speeds these customers had during these
> tests?

What that work showed was that basically all cablemodems had a fixed
upstream buffersize that is too large by factors of 25% to a factor of
10, and that 48Kbytes was a pretty good basic sweet spot... and if
they could just fix that across what's deployed life would get better
for everybody without fancy schmancy aqms... But we knew that
already....

http://www.dslreports.com/speedtest/results/bufferbloat?up=1

I note that I was called into consult a bit on this project and don't
feel at liberty at the moment to disclose their up/down parameters or
the direction of future work. Carl's nanog talk was filmed and there
were some interesting discussion afterwards about things like BBR.

https://www.youtube.com/watch?v=cA8FPHr8h7U&list=PLO8DR5ZGla8hcpeEDSBNPE5OrZf70iXZg&index=16

I was delighted that they used flent to exercise the connection(s).

> 96 kilobyte buffer on 1 megabit/s upstream or 50 megabit/s upstream makes a
> big difference.
>
> (I have 250/50 on my DOCSIS3.0 connection, but perhaps it's common knowledge
> what speeds Comcast customers typically has, that I don't know?)
>
> --
> Mikael Abrahamsson    email: swmike at swm.pp.se
>
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-- 
Dave Täht
Let's go make home routers and wifi faster! With better software!
http://blog.cerowrt.org