[Cerowrt-devel] my thx to spacex (and kerbal space program) forcheering me up all year

Dave Taht dave.taht at gmail.com
Sun Jan 3 00:48:18 EST 2021


On Sat, Jan 2, 2021 at 1:39 PM Scott Manley <scottmanley1972 at gmail.com> wrote:
>
> Oh but I'm fascinated by the discussion of Starlink's network performance.!

 I HAD figured that everyone at starlink has read about how NOT to
build a space-born
packet switched network. If you haven't read it, "Eccentric Orbits:
The Iridium Story" is a great read.

I have had quite the hobby trying to grok what starlink is up to, I
can go into it here if you like. I can't remember how much of the
bufferbloat problem I'd discussed with you at the last hackers
conference.

PS (can you pleeeeeze record you singing over your part in that song? :) )
>
> On Sat, Jan 2, 2021 at 9:17 AM Dave Taht <dave.taht at gmail.com> wrote:
>>
>> Taking scott manley off the cc. As much as I would like him to sit in
>> on that song, I don't think he cares about bufferbloat as much as Id
>> like him to.... I do wish I knew someone that could just magically get
>> the bufferbloat issue raised within
>> starlink effectively....
>>
>> On Fri, Jan 1, 2021 at 3:31 PM David P. Reed <dpreed at deepplum.com> wrote:
>> >
>> > It has bufferbloat?
>>
>> Yep. See links below.
>>
>> > Why am I not surprised?
>>
>> I was surprised given the length of the talk I'd had with their VP,
>> eng, but I do figure that getting the thing working at all
>> was a greater challenge than tackling our issue. I've long worried of
>> course, that the mac layer on this thing was going to be very weird,
>> and since they were working with qca they'd end up buring everything
>> in the network offload processors, even though at present speeds the
>> cpu they are using is *loafing*, Im not as optimistic as jon is as to
>> how easy the port of cake or fq_codel would be to their hardware as it
>> is variable bandwidth and thus needs bql-like backpressure.
>>
>>
>> Since there doesn't seem to be a gpl drop yet we don't know a lot,
>> however there was a teardown of the hw and jim's posting and a start
>> at testing on reddit - the dslreports test was flawed in that ping did
>> not work at all....
>>
>> https://www.reddit.com/r/Starlink/comments/k0dwon/starlink_and_bufferbloat_testing/
>>
>> rate limiting with sqm works:
>>
>> https://www.reddit.com/r/Starlink/comments/jxkef9/ahat_is_your_starlinks_bufferbloat_score/
>>
>> and the starlink teardown was good:
>> https://www.reddit.com/r/hardware/comments/kchxl8/starlink_teardown_and_analysis/
>>
>> We think that this hardware actually has fq_codel AND hw rate limiting
>> in it. But that's not the right thing for a starlink up or downlink
>> which is variable rate.
>>
>> any I know at least 5 people on the beta list and maybe we can get
>> better testing done in the next month or two.
>>
>> It would of course be great if somehow we could get loud enough for
>> musk to tweet back or hire one of us to help 'em get it right.... I
>> had a friend of mine send him a suitably inscribed copy of toke's
>> "bufferbloat and beyond" via interoffice mail... but finding someone
>> up there more focused on the terminal software itself would be better.
>> I mean low latency should be their bread and butter and while Im sad
>> that the early tests are dismal, I am pretty confident that ultimately
>> they will get it right.
>>
>> > I can share that one stack hasn't had it from the start, by design. That is one implemented for trading at 10+ GB/sec, implemented in Verilog, and now apparently in production use at one of the largest NY trading intermediaries.
>>
>> Yea!
>>
>> >
>> > Why? Simply two reasons:
>> >
>> > 1. People who design parallel hardware systems are trained to focus on closing timing constraints. Which means never using FIFOs that are longer than absolute minimum. The designer is a VLSI designer by trade, not a networking guy.
>> >
>> > 2. Trading is all about managing delay. In this case, 100 msec packet delay is worst allowable case end to end.
>> >
>> > Yet it is full TCP in hardware.
>> >
>> > Can't share more, because I don't know more, it being all proprietary to the bank in question.
>> >
>> > Now, one wonders: why can't Starlink get it right first time?
>> >
>> > It's not like bufferbloat is hard on a single bent pipe hop, which is all Starlink does today.
>> >
>> > -----Original Message-----
>> > From: "Dave Taht" <dave.taht at gmail.com>
>> > Sent: Thu, Dec 31, 2020 at 1:37 pm
>> > To: "bloat" <bloat at lists.bufferbloat.net>, "cerowrt-devel" <cerowrt-devel at lists.bufferbloat.net>, "Scott Manley" <scottmanley1972 at gmail.com>
>> > Cc: "bloat" <bloat at lists.bufferbloat.net>, "cerowrt-devel" <cerowrt-devel at lists.bufferbloat.net>, "Scott Manley" <scottmanley1972 at gmail.com>
>> > Subject: [Cerowrt-devel] my thx to spacex (and kerbal space program) forcheering me up all year
>> >
>> > If it wasn't for such a long list of wonderful accomplishments in
>> > space, it would have been a sadder year. i just re-recorded my song
>> > "one first landing" out on my dinghy:
>> >
>> > https://www.youtube.com/watch?v=wjur0RG-v-I&feature=youtu.be
>> >
>> > Maybe someday I'll get scott manley to do his verse on this. Try as I
>> > might over the past few years, I still can't cop his accent.
>> >
>> > Now if we can only fix starlink's bufferbloat! It looks to me like the
>> > firmware is QCA's openwrt derivative...
>> >
>> > --
>> > "For a successful technology, reality must take precedence over public
>> > relations, for Mother Nature cannot be fooled" - Richard Feynman
>> >
>> > dave at taht.net  CTO, TekLibre, LLC Tel: 1-831-435-0729
>> > _______________________________________________
>> > Cerowrt-devel mailing list
>> > Cerowrt-devel at lists.bufferbloat.net
>> > https://lists.bufferbloat.net/listinfo/cerowrt-devel
>> >
>> >
>>
>>
>> --
>> "For a successful technology, reality must take precedence over public
>> relations, for Mother Nature cannot be fooled" - Richard Feynman
>>
>> dave at taht.net <Dave Täht> CTO, TekLibre, LLC Tel: 1-831-435-0729



-- 
"For a successful technology, reality must take precedence over public
relations, for Mother Nature cannot be fooled" - Richard Feynman

dave at taht.net <Dave Täht> CTO, TekLibre, LLC Tel: 1-831-435-0729


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