[Cake] Cake strange behaviour
dave at taht.net
Sat Jul 16 08:44:00 EDT 2016
On 7/16/16 1:53 PM, Kevin Darbyshire-Bryant 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?
Without extensive testing I have no faith that the current aqm
implementation in cake is actually working. In the case of inbound
traffic, managed at the cpe rather than at the isp, fq alone does not
manage to reduce queue length.
As for the actual characeristics of microsofts new distribution system,
I have heard many reports of it slamming networks, but have no traces
to work from. A suggestion to get some would be to put a freshly
installed windows box on the network and capture all that happens.
>> 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
>>> 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.
>>> Cake mailing list
>>> Cake at lists.bufferbloat.net
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