[Bloat] dslreports bufferbloat tests

[jb]

Regarding picking up advanced congestion management in a result, it
would be possible by adding a concurrent tcpdump on each test server -
running all the time and filtering for the appropriate bits.

But am I just looking for "ECN capable" flags originating from a given
public IP?
or am I filtering just for CE marks (11), indicating there was some
active queue management actually going on -- and only that would be
worth mentioning?

thanks


On Thu, Apr 7, 2016 at 1:30 AM, Dave Taht <dave.taht at gmail.com> wrote:
> On Tue, Apr 5, 2016 at 8:19 PM, jb <justinbeech at gmail.com> wrote:
>> I take your point regarding Quality
>
> Thx! I am not grumpy at you in particular, but at a world that
> continues to view packet loss as completely undesirable (I was at
> several ietf meetings like that yesterday, and 2 days ago the
> FCC's "nutrition labels for broadband" got a lot of press:
> http://arstechnica.com/business/2016/04/fccs-nutrition-labels-for-broadband-show-speed-caps-and-hidden-fees/
> )
>
> Does anyone know how these nutrition labels are calculated?
>
>> but both your examples in the post show A+ quality?
>
> Well, yes... :) I did both of those with ecn on. (I did also get an A+
> with ecn off)
>
> "desirable" packet loss, varies based on the number of flows, the
> targetted queuing delay, the bandwidth of the link, the tcp, and the
> RTT. It rapidly drops into the low percentage points for this
> particular test,for those particular parameters.
>
> as for:
>
> "Quality Grades
>
> Quality refers to average detected packet loss / re-transmit
> percentages during download phase. The higher the packet loss /
> re-transmit percentage the more inefficient the connection is, and a
> very poor result may be indicative of congestion, inside wiring issues
> or other problems that need addressing.
>
> "1% or less - A+
> 2.5% or less - A
> 3% or less - B
> 5% or less - C
> 12% or less - D
> over 12% - F"
>
> What I specifically objected to was this formula for calculating the
> grade. After stewing about it a while (um, er, *years*, now), I
> realized last night that with a little work, now that we know what
> aqms such as pie and fq_codel can achieve, that we could, indeed, get
> a desirable range of "packet loss" for X flows, Y RTT, and Z
> bandwidth.
>
> btw: Does your test have the ability to track "CE" marks? That would
> be like a "gold star" affixed to the test report. (latest IoS has some
> support for ecn now by default)
>
>> I'm thinking that packet loss significant enough to show as a "C" or
>> worse is mostly a bad situation
>
> I pointed at a case where 25% packet loss was good here.
>
> http://localhost:1313/post/rtt_fair_on_wifi/
>
> I am tempted to build on this theme, because it is not intuitive that
> desirable loss is a curve - a lot at low rates, but at higher rates,
> much less loss occurs and and really high rates one loss hurts...
>
>> even if avoiding all packet loss - by using huge buffers - is
>> definitely a disaster..
>
> Yes. 0 and major bufferbloat would be an F grade for me, for "Quality" :)
>
> In other news, I sure wish the cable modems out there had followed
> these guidelines at least.
>
> http://www.cablelabs.com/wp-content/uploads/specdocs/CM-GL-Buffer-V01-110915.pdf
>
>>
>>
>> On Wed, Apr 6, 2016 at 12:21 PM, Dave Taht <dave.taht at gmail.com> wrote:
>>> On Tue, Apr 5, 2016 at 6:33 PM, Brandon Applegate <brandon at burn.net> wrote:
>>>>
>>>>> On Apr 5, 2016, at 9:04 PM, Dave Taht <dave.taht at gmail.com> wrote:
>>>>>
>>>>> Does anyone know what the "quality" portion of dslreport's metric means?
>>>>
>>>> Basically - packet loss.
>>>>
>>>> https://www.dslreports.com/faq/17930
>>>
>>> Sigh. I ranted. I might rant harder.
>>>
>>> http://blog.cerowrt.org/post/bufferbloat_vs_quality/
>>>
>>>>
>>>> —
>>>> Quality Grades
>>>>
>>>> Quality refers to average detected packet loss / re-transmit percentages during download phase. The higher the packet loss / re-transmit percentage the more inefficient the connection is, and a very poor result may be indicative of congestion, inside wiring issues or other problems that need addressing.
>>>>
>>>> 1% or less - A+
>>>> 2.5% or less - A
>>>> 3% or less - B
>>>> 5% or less - C
>>>> 12% or less - D
>>>> over 12% - F
>>>> —
>>>>
>>>>
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