[Cerowrt-devel] Problems testing sqm

Richard Smith smithbone at gmail.com
Fri Oct 23 16:18:25 EDT 2015


On 10/23/2015 02:41 PM, Michael Richardson wrote:
> Richard Smith <smithbone at gmail.com> wrote:
>      > My test setup:
>
>      > Laptop<--1000BaseT-->DUT<--1000baseT-->Server
>
> So, given that the DUT is the only real constraint in the network, what
> do you expect to see from this setup?
>
> Given that the probably DUT can't forward at Gb/s, and it certainly can't
> shape anything, it's gonna drop packets, and it's probably gonna drop them in
> Rx, having overrun the Rx-queue (so tail-drop).  If there is too much ram
> (bufferbloated), then you'll see different results...

Setting ingress/egress to 10Mbit/s I expected to see the speed 
measurements bounce around those limits with the ping times staying in 
the low double digits of ms.  What I saw however, was the data rates 
going well past 10Mbit limit and pings up to 2000 ms.

This is what I've seen in prior rrul testing using a the 50/10 cable 
link at our office and my 25(ish)/6 link at my apartment and a well 
connected server on the net.  That however was using QoS and not SQM.

Its that a reasonable expectation?

-- 
Richard A. Smith



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