On July 16, 2016 1:53:20 PM GMT+02:00, Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk> wrote:

On 16/07/16 11:59, Dave Täht wrote:
I would repeat the same test with htb+fq_codel.

Hi Dave,

That's more challenging than it sounds - reproducing the test scenario
would require the windows box going back in time. What could it be
doing that so far any of the flent tests fail to replicate? Hmmm, so
far I've used a local flent server...I wonder if RTT is at play here?

Kevin

On 7/16/16 11:35 AM, Kevin Darbyshire-Bryant wrote:
Hi guys,

Encountering some behaviour that I don't understand. Line is a 40/10
cake limited to 39000/9840. Overheads 12, 'dual-dsthosts' in ingress,
'dual-srcshosts' on engress - limiting the on the WAN line. Take a look
at my ping response graph

http://www.thinkbroadband.com/ping/share/9822cb5160582fa6abee29b60d807766-16-07-2016.html

Around 20:30 I fired up a windows machine that was behind on its updates
so it generated a bit of ingress traffic. Note the comparatively high
latency (40ms) and stupidly high ping packet loss (50%) The 3-5ms
steady (blue) latency you can see is a system backup (so egress traffic)
running till around 23:00.

The really strange bit is that cake stats show it has only dropped 10
(yes 10!) packets.

I'm not the only person encountering 'interesting' behaviour with regard
to windows updates inducing high latency and high packet loss. It's as
if cake weren't there managing flows and this is the ISP's rate limiter
in action.

Kevin

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