Re: [Bloat] extremely good dslreports result for bufferbloat on free.fr

[Dave Taht <dave.taht@gmail.com>]

On Thu, Apr 30, 2015 at 11:31 PM, jb <justin@dslr.net> wrote:
>>This got an A+ rating, which I would not have given it, given the
> enormous load spike.
>
> I think there will always be the occasional incorrectly graded test,
> this one is simply because the median of the downstream latency
> ignores the spike. If I used average(), then it would not ignore
> the spike, however one very high outlier could also ruin a good result.
> After all, pinging anything on the internet can always get the odd
> bad response now and again.


> If neither average nor median is any good, then there needs to be
> a filter function. But what filter? ignoring spikes that are hugely higher
> than neighbouring ones? that would fail if there was a spike every 3rd
> sample. Open to ideas..

98th percentile across the cdf? (It would be interesting to calculate
this across your data set thus far, regardless)

Use two measurements  - one of jitter one of median latency increase?

> Here is a result from the australian telco free public hotspot:
>     http://www.dslreports.com/speedtest/399962
>
> On the side of the hotspot it says 'send us your thoughts about this
> free service'. Well my thought is that if one person posted a picture
> to Instagram, the whole hotspot would be unusable for as long as it
> took to upload. 6 seconds of buffer in there somewhere.

Gotta start somewhere....

>
> cheers,
>
> On Fri, May 1, 2015 at 4:05 PM, Dave Taht <dave.taht@gmail.com> wrote:
>>
>> This got an A+ rating, which I would not have given it, given the
>> enormous load spike.
>>
>> http://www.dslreports.com/speedtest/400387
>>
>> Imagine if your steering wheel behaved like this.
>>
>> On Thu, Apr 30, 2015 at 8:10 PM, jb <justin@dslr.net> wrote:
>> > Already users are like "how can i fix this!".
>>
>> The FAQ can be improved.
>>
>> > I've just replied to one who has lower speeds on the surfboard SB6141
>> > which
>> > is a modem designed for crazy cable speeds. He has an "F" and his
>> > downstream
>> > bloat is terrible, and upstream not much better.
>> >
>> > I imagine a LOT of people on slower plans have a "recommended" modem
>> > like
>> > this one.
>>
>> I have not found a cable modem with less than 250ms bloat at 50mbit/5.
>> The docsis 3 ones
>> are often in the 800 ms range.
>>
>> >
>> > However most of them will hear that the problems from bloat only happen
>> > when
>> > you reach maximum upload or download speed and will think, well, I can
>> > live
>> > with that, I never run my connection to capacity and I don't upload to
>> > offsite backups..
>>
>> Latency spikes are annoying no matter how they are inflicted, and happen
>> all the time on nearly any workload. Your test is testing tcp in steady
>> state,
>> most web transactions are bursts of dozens to a hundred flows in slow
>> start.
>>
>> It is the business class customers that feel it most often. I have never
>> visited a business class cable customer that had reasonable amounts of
>> delay
>> and jitter during business hours.
>>
>> After living in  bloat-free universe for quite some time now, annoying
>> issues with things like netflix are decreased, voip and videoconferencing
>> work all the time, same for games...
>>
>> it would be hard to create a metric
>> for user satisfaction, but every before/after comparison someone
>> implementing a solution is quite overjoyed.
>>
>> https://twitter.com/mnot/status/575581792650018816
>>
>> >
>> > On Fri, May 1, 2015 at 10:48 AM, Rich Brown <richb.hanover@gmail.com>
>> > wrote:
>> >>
>> >>
>> >> > On Wed, Apr 29, 2015 at 9:33 PM, jb <justin@dslr.net> wrote:
>> >> > ...
>> >> >> if it did get a rating it would be an "D" or "F"..
>> >> >
>> >> > How about "E" for error? That can be further explained in the text
>> >> > "Sometimes the bloat is so bad that we cannot adaquately test for it
>> >> > -
>> >> > and other times there is something else badly wrong with the link
>> >> > that
>> >> > we cannot identify."
>> >>
>> >> I would stay away from a letter grade for that state, since it could
>> >> appear to be on the continuum of A+, A, B, C, D, E (?) F...
>> >>
>> >> Better to give it a "-" or "?" mark. And if they hover over the "?",
>> >> let
>> >> the text show: "Sometimes the bloat is so bad that we cannot adaquately
>> >> test
>> >> for it - and other times there is something else badly wrong with the
>> >> link
>> >> that we cannot identify."
>> >>
>> >> Rich
>> >
>> >
>>
>>
>>
>> --
>> Dave Täht
>> Open Networking needs **Open Source Hardware**
>>
>> https://plus.google.com/u/0/+EricRaymond/posts/JqxCe2pFr67
>
>



-- 
Dave Täht
Open Networking needs **Open Source Hardware**

https://plus.google.com/u/0/+EricRaymond/posts/JqxCe2pFr67