Hi Fred,
On Feb 24, 2014, at 16:24 , Fred Stratton <[email protected]> wrote:
> 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.
But the current rate given by the modem is a pretty true measurement of
the bandwidth between the modem and the DSLAM, independent on the marketing
numbers of the ISP ;)
> How long is your line? Downstream attenuation is a proxy for this.
Once the sync is working this does not matter any more, having seen
Rich's line stats, he has a very clean ADSL with SNRM of 22 and 11 and almost
no errors (not even many FECs).
Best Regards
Sebastian
> 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 3.10.28.14.
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>
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