[LibreQoS] LibreQoS upstream + Cake/FQ_Codel in CPE Router?

[Dave Taht]

On Mon, Sep 11, 2023 at 9:18 AM Dave Taht <dave.taht at gmail.com> wrote:

> Most of our users are in the libreqos chat, and you will in general get
> fasters responses there than here.
>
>
> On Sun, Sep 10, 2023 at 7:35 PM Ignacio Ocampo via LibreQoS <
> libreqos at lists.bufferbloat.net> wrote:
>
>> Hi all,
>>
>> Is it recommended (or not), to run Cake/FQ_Codel in CPE routers, even if
>> LibreQoS is running upstream?
>>
>
> We recommend running cake on the CPE up, and LibreQos to manage the down.
> It is very helpful to have cake running in nat mode on the actual device
> doing nat (and in that case managing the down also at that device can help)
>
> We recommend using wifi routers that run fq_codel natively on the wifi,
> also, as at higher rates the bottlenecks' bloat shift to the wifi.
>
> https://lwn.net/Articles/705884/
>
> Many devices support fq_codel on the wifi natively, the eero 5, evenroute,
> and many gl.inet products do.
>
>>
>> If so, which are the advantages?
>>
>
> Running cake on the actual bottleneck  prevents malignant traffic from
> escaping the home network. A mere ping flood can be controlled by libreqos,
> but it is better to slow that down and mix it up with all the other traffic
> at the cpe. The algorithms for ack-filtering and congestion management are
> always more accurate when put on the actual bottleneck.
>

To clarify this a bit further, by default libreqos ships with two
parameters that actually override the overall settings somewhat. We
multiply by 1.09 by default to allow for sufficient slop to look good on
speedtest,
and have another parameter that helps modify the per hop transit settings.

What you were sort of suggesting below is conciously underprovisioning the
cpe, where by default we already overprovision libreqos.

>
> Also, I'm assuming I will have to set up the router with a lower bandwidth
>> than the assigned by LibreQoS?
>>
>
> yes.
>
>>
>> For instance, if LibreQoS is assigning 13Mbit to the customer, the router
>> (with Cake or FQ_Codel) enabled need to have a limit of ~11Mbit?
>>
>
> On up from the cpe traffic, you should be able to use the same number as
> you use in libreqos. For shaping the down at the cpe the historical
> recommendation has always been 85-90%, but with libreqos managing that, no
> shaping of the down is needed, although I do call out the nat case as a
> potential exception.
>
>
>>
>> Please advise. Thanks!
>>
>> --
>> Ignacio Ocampo
>>
>> _______________________________________________
>> LibreQoS mailing list
>> LibreQoS at lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/libreqos
>>
>
>
> --
> Oct 30:
> https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html
> Dave Täht CSO, LibreQos
>


-- 
Oct 30: https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html
Dave Täht CSO, LibreQos
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