[Cerowrt-devel] routers you can throw off the back of a truck

Valent Turkovic valent at otvorenamreza.org
Mon Jan 18 04:43:28 EST 2016

Hi Jonathan,

On Mon, Jan 18, 2016 at 9:30 AM, Jonathan Morton <chromatix99 at gmail.com> wrote:
>> On 18 Jan, 2016, at 02:45, Valent Turkovic <valent at otvorenamreza.org> wrote:
>> Is there anyway to configure any queuing technique in Linux kernel
>> that so it distributes bandwidth equally between users and to keep lag
>> (bufferbloat) as low as possible, but without needing to define
>> absolute values for download and upload.
> Recent versions of Cake have an “autorate_ingress” flag, which can track capacity when deployed on the downstream end of the link.  I use it myself to assist with 3G, where downlink quality and contention vary frequently.

Just found your presentation [1] and this could be what I'm looking
for... and I'm very interested to test it further. My initial tests
[2] of piece_of_cake and layered_cake didn't show it in good light, it
had quite high latency when compared with other sqm scripts in
OpenWrt. Any ideas why? I have 100/10 Mbps fiber connection and during
the test I put 90/9 Mbps limit in SQM and got those results.

Can you please share your sqm qos script, or just how you invoke tc
manually and I'll test it on my routers and see what happens then:)

> I haven’t yet found a robust way to automatically sense link capacity from the upstream side.  You’ll therefore need to set a conservative static value for the uplink capacity.
>  - Jonathan Morton

>From your presentation I see that if we had a daemon working in
background and somehow measured tcp latency (how?) and then we could
use it to raise/lower bandwidth limits on cake until we get best
possible results. Ideally I would like to use a queueing mechanism
that auto-configures everything.

@everybody any ideas how to tweak current "simple.qos" and
"simplest.qos" scripts in OpenWrt for 3G and fiber optics? On fiber
optic connection idle latency is around 30ms and on 3G connection is
around 60ms, do I need to change 5ms default in fq_codel to these
values? How?


[1] http://www.bufferbloat.net/attachments/224/cake-battlemesh-v8.pdf
[2] http://pastebin.com/raw/BcizDmVX

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