[Cake] Advantages to tightly tuning latency

Dave Taht dave.taht at gmail.com
Tue Apr 21 18:44:01 EDT 2020

On Tue, Apr 21, 2020 at 3:33 PM Jonathan Morton <chromatix99 at gmail.com> wrote:
> > On 22 Apr, 2020, at 1:25 am, Thibaut <hacks at slashdirt.org> wrote:
> >
> > My curiosity is piqued. Can you elaborate on this? What does free.fr do?
> They're a large French ISP.  They made their own CPE devices, and debloated both them and their network quite a while ago.  In that sense, at least, they're a model for others to follow - but few have.
>  - Jonathan Morton

they are one of the few ISPs that insisted on getting full source code
to their DSL stack, and retained the chops to be able to modify it. I
really admire their revolution v6 product. First introduced in 2010,
it's been continuously updated, did ipv6 at the outset, got fq_codel
when it first came out, and they update the kernel regularly. All
kinds of great features on it, and ecn is enabled by default for those
also (things like samba). over 3 million boxes now I hear....

with <1ms of delay in the dsl driver, they don't need to shape, they
just run at line rate using three tiers of DRR that look a lot like
cake. They shared their config with me, and before I lost heart for
future internet drafts, I'd stuck it here:


Occasionally they share some data with me. Sometimes I wish I lived in
paris just so I could have good internet! (their fiber offering is
reasonably buffered (not fq_codeled) and the wifi... maybe I can get
them to talk about what they did)

When free.fr shipped fq_codel 2 months after we finalized it, I
figured the rest of the world was only months behind. How hard is it
to add 50 lines of BQL oriented code to a DSL firmware?

Make Music, Not War

Dave Täht
CTO, TekLibre, LLC
Tel: 1-831-435-0729

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