[Cerowrt-devel] Equivocal results with using 3.10.28-14

Fred Stratton fredstratton at imap.cc
Mon Feb 24 10:24:25 EST 2014

How are you measuring the link speed?

With SQM enabled, I have speedtest.net results far below the values at 
which the gateway syncs.

IF the gateway syncs at 12000/1000, the speedtest figures are 9500/850

The performance I obtain with streaming video is very good, tweaking the 
extra settings in SQM on 3.10.28-16

I am sure you are aware that you will never achieve the values quoted by 
the ISP. How long is your line? Downstream attenuation is a proxy for 
this. Are you using ADSL2+, or some other protocol? Does the device even 
tell you?

On 24/02/14 14:36, Rich Brown wrote:
> CeroWrt 3.10.28-14 is doing a good job of keeping latency low. But... it has two other effects:
> - I don't get the full "7 mbps down, 768 kbps up" as touted by my DSL provider (Fairpoint). In fact, CeroWrt struggles to get above 6.0/0.6 mbps.
> - When I adjust the SQM parameters to get close to those numbers, I get increasing levels of packet loss (5-8%) during a concurrent ping test.
> So my question to the group is whether this behavior makes sense: that we can have low latency while losing ~10% of the link capacity, or that getting close to the link capacity should induce large packet loss...
> Experimental setup:
> I'm using a Comtrend 583-U DSL modem, that has a sync rate of 7616 kbps down, 864 kbps up. Theoretically, I should be able to tell SQM to use numbers a bit lower than those values, with an ATM plus header overhead with default settings.
> I have posted the results of my netperf-wrapper trials at http://richb-hanover.com - There are a number of RRUL charts, taken with different link rates configured, and with different link layers.
> I welcome people's thoughts for other tests/adjustments/etc.
> Rich Brown
> Hanover, NH USA
> PS I did try the 3.10.28-16, but ran into troubles with wifi and ethernet connectivity. I must have screwed up my local configuration - I was doing it quickly - so I rolled back to
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