300+ms of hotel wifi bufferbloat - peaking at 1.5 sec!

Mon Jun 1 20:15:23 UTC 2015

On Mon, Jun 1, 2015 at 11:58 AM, Josh Reynolds <josh at spitwspots.com> wrote:
> There's a bit of discussion on the AFMUG list about that speed test Dave.
> People with 500Mb, 1Gb,10Gb pipes were getting drastically different results
> depending on what "type" of test they did.

There were also huge discussions of the dslreports testing ideas on
the bufferbloat "bloat" list.

Along the way we came up with some ideas and recommendations, which we
piled into a document here (comments welcomed!)

https://docs.google.com/document/d/1z5NN4WRKQKK-RtxtKR__XIwkybvsKEmunek2Ezdw_90/edit

I would like it very much if the currently named "fiber,cable,dsl,
etc" options in the dslreports test were renamed something like
"insane, extreme, medium, low" and let users call out a wifi or
wireless test vs

A big flaw in it as structured is that it first tests how robust a
network is to lots of flows in slow start in the early stages of the
test.  The median idea = a grade needs work, also. But see above doc
and comment, please.

Also I have never trusted a browser to be able to drive tests like
this sanely, but I was pretty satisfied that the results I was getting
on the hardware I had (up to about 120Mbit) matched realities I could
also measure with the "flent.org" (formerly netperf-wrapper) tool. thx
for the steer to testers at higher rates.

Still, I would trust flent a LOT further than a browser at speeds
higher than that. It has been tested with reasonable results up to
40gigE.

>
> Josh Reynolds
> CIO, SPITwSPOTS
> www.spitwspots.com
>
>
> On 06/01/2015 10:52 AM, Dave Taht wrote:
>>
>> I did the dslreports tests on the NANOG wifi while listening to srikanth
>> today:
>>
>> http://www.dslreports.com/speedtest/593926
>>
>> And my own (flent data also in this dir)...
>>
>> http://snapon.lab.bufferbloat.net/~d/nanog/download_cdf.png
>>
>> pretty good bandwidth. Pretty horrific latency... a couple detours
>> around the moon.
>>
>>
>> On Sat, May 30, 2015 at 6:59 PM, Srikanth Sundaresan
>> <srikanth at gatech.edu> wrote:
>>>
>>> While I agree that upload speeds aren't great, it doesn't mean that the
>>> buffers aren't big. Buffer sizes of the order of MB's are uncalled for at
>>> the edge, unless we're talking really high speeds. The miniscule
>>> performance
>>> increase for single TCP flows doesn't really justify the potential
>>> increase
>>> in latency for everyone else.
>>>
>>>
>>> On 5/30/15 6:25 PM, Steven Tardy wrote:
>>>>
>>>> There's a corollary of the bufferbloat phenomenon: buffer drain time.
>>>> It's
>>>> not the size of the buffer, but how long it takes to empty. And US ISPs
>>>> continue to say "customers don't want upload speed".
>>>> If the ISP upload speed was symmetric you'd likely never notice the
>>>> 1-2MB
>>>> of buffers.
>>>>
>>>> I guess what I'm getting at is why do you continue to say buffers are
>>>> too
>>>> big instead of saying ISP upload is too slow?
>>>>
>>>>
>>>>> On May 30, 2015, at 1:50 PM, Dave Taht <dave.taht at gmail.com> wrote:
>>>>>
>>>>> http://www.dslreports.com/speedtest/578850
>>>>>
>>>>> I would get a kick out of it if folk here tried this new speedtest
>>>>> periodically (on the "cable" setting) during the nanog conference. ;)
>>>>> There is a hires option for more detail on the resulting charts...
>>>>>
>>>>> (or fiddled with "flent" (flent.org))
>>>>>
>>>>> --
>>>>> Dave Täht
>>>>> What will it take to vastly improve wifi for everyone?
>>>>> https://plus.google.com/u/0/explore/makewififast
>>
>>
>>
>

-- 
Dave Täht
What will it take to vastly improve wifi for everyone?
https://plus.google.com/u/0/explore/makewififast