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

[Rich Brown <richb.hanover@gmail.com>]

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.