Re: [Starlink] Network quality for rocket scientists

["Bjørn Ivar Teigen" <bjorn@domos.no>]

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Hi Sebastian, thank you for the feedback.

"See the problem? Buffers produce jitter!"
>
>
> I would rephrase that as "over-sized and under-managed" buffers increase
> jitter unduly. Interestingly, bound jitter can be converted into static
> latency by using, wait for it, (delay) buffers and a scheduler.
>

You are absolutely right. I was hoping someone would spot that! There is
one problem with that approach though. To actually remove the jitter the
scheduler can no longer be work-conserving (needs delay as you also point
out), and that increases TCP ramp-up times (among other things). Can be a
hard sell. I think the benefits outweigh the costs though, so I would do it
your way.

>
> > Only nit is at the conclusion... the benefits of applying fair queuing
> > to level out apparent jitter is well demonstrated at this point, for
> > most kinds of traffic. Wish you'd mentioned it.
>
>         I rather wish low latency DOCSIS (LLD) aka L4S's primary
> driver/use-case would not have been mentioned before it has been properly
> tested and confirmed delivering on its promises. Because most of what L4S
> offers/mandates for jitter reduction is "hopes and prayers", aka end-points
> are supposed to behave well... in fairness LLD at least has a poor man's FQ
> on board in the guise of "queue protection" (with by default like 32
> "buckets")... some of the cost of FQ with only few of its benefits...
>
Fair enough, time will show!


> Regards
>         Sebastian
>
>
>
> >
> >
> > On Mon, Feb 14, 2022 at 7:07 AM Bjørn Ivar Teigen <bjorn@domos.no>
> wrote:
> >>
> >> Hi everyone,
> >>
> >> I was inspired by the latest Starship presentation to write a piece on
> network quality in the language of rocket science. The blog can be found
> here:
> https://www.domos.no/news-updates/network-quality-for-rocket-scientists
> >>
> >> Cheers,
> >> Bjørn Ivar Teigen
> >>
> >> --
> >> Bjørn Ivar Teigen
> >> Head of Research
> >> +47 47335952 | bjorn@domos.no | www.domos.no
> >> WiFi Slicing by Domos
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> >
> >
> >
> > --
> > I tried to build a better future, a few times:
> > https://wayforward.archive.org/?site=https%3A%2F%2Fwww.icei.org
> >
> > Dave Täht CEO, TekLibre, LLC
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>

-- 
Bjørn Ivar Teigen
Head of Research
+47 47335952 | bjorn@domos.no <name@domos.no> | www.domos.no
WiFi Slicing by Domos

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