[Cerowrt-devel] SQM Question #3: How shall we recommend people set their upload/download speeds?

[Sebastian Moeller]

Hi list,
On Dec 29, 2013, at 09:53 , Dave Taht <dave.taht at gmail.com> wrote:

> On Sat, Dec 28, 2013 at 8:33 PM, Rich Brown <richb.hanover at gmail.com> wrote:
>> QUESTION #3: How shall we recommend people set their upload/download speeds?
>> 
>> Although we have already spent a lot of time on the list batting around ways to think about this, it seems to me that there are only two choices for recommendations, especially given that most people looking at CeroWrt are in a “TL;DR” mind set:
> 
> What does TL;DR mean?

	Too Long; Didn't Read...

> 
>> 1) If you don’t have an accurate sense of your actual link speed (e.g., you haven’t done a link speed measurement), you should take your provider’s published specs, knock them down by 15%, and enter those values in the SQM Basic Settings tab. [Or should they take an additional 15% off that already reduced value?]
> 
> 92% on the up, 85% on the down are starting points.
> 
>> 
>> 2) If you have done measurements of your link speed, you should enter values that are 95% of each direction’s measured speed.
>> 
>> Is this the right recommendation?

	That is what I thought, but it seems 95% was too optimistic… I have found that ShaperProbe's (http://www.measurementlab.net/tools/shaperprobe) capacity estimate is pretty good at least for the low speeds I could test.


> A short rant on the inadaquacy of speedtest and other tests would be
> nice. Netanalyzr is the closest thing to a good test these days but it
> requires java and is inaccurate above 20mbit.

	The problem is that no one really wants to supply the large amount of bandwidth required that everyone can max out their download long enough for a reasonable test; this is why an often read recommendation is to use curl or wget to concurrently down or up load large files from several beefy servers, to actually be able to assess the local link capacity. The only redeeming feature of seediest and friends is, that underestimating the available link capacity will lead to decent latency and lean buffers :).

best
	Sebastian

> 
>> 
>> NB: In the Details… section, we can recommend ways to measure current link speeds, encourage people to make the measurement during quiet times, link to the “Quick test for Bufferbloat” page, etc. for those who want to dig further.
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> 
> 
> 
> -- 
> Dave Täht
> 
> Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html
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