Re: [Starlink] insanely great waveform result for starlink

[Nathan Owens <nathan@nathan.io>]

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I’ll run my visualization code on this result this afternoon and report
back!

On Fri, Jan 13, 2023 at 9:41 AM Jonathan Bennett via Starlink <
starlink@lists.bufferbloat.net> wrote:

> The irtt command, run with normal, light usage:
> https://drive.google.com/file/d/1SiVCiUYnx7nDTxIVOY5w-z20S2O059rA/view?usp=share_link
>
> Jonathan Bennett
> Hackaday.com
>
>
> On Fri, Jan 13, 2023 at 11:26 AM Dave Taht <dave.taht@gmail.com> wrote:
>
>> packet caps would be nice... all this is very exciting news.
>>
>> I'd so love for one or more of y'all reporting such great uplink
>> results nowadays to duplicate and re-plot the original irtt tests we
>> did:
>>
>> irtt client -i3ms -d300s myclosestservertoyou.starlink.taht.net -o
>> whatever.json
>>
>> They MUST have changed their scheduling to get such amazing uplink
>> results, in addition to better queue management.
>>
>> (for the record, my servers are de, london, fremont, sydney, dallas,
>> newark, atlanta, singapore, mumbai)
>>
>> There's an R and gnuplot script for plotting that output around here
>> somewhere (I have largely personally put down the starlink project,
>> loaning out mine) - that went by on this list... I should have written
>> a blog entry so I can find that stuff again.
>>
>> On Fri, Jan 13, 2023 at 9:02 AM Jonathan Bennett via Starlink
>> <starlink@lists.bufferbloat.net> wrote:
>> >
>> >
>> > On Fri, Jan 13, 2023 at 6:28 AM Ulrich Speidel via Starlink <
>> starlink@lists.bufferbloat.net> wrote:
>> >>
>> >> On 13/01/2023 6:13 pm, Ulrich Speidel wrote:
>> >> >
>> >> > From Auckland, New Zealand, using a roaming subscription, it puts me
>> >> > in touch with a server 2000 km away. OK then:
>> >> >
>> >> >
>> >> > IP address: nix six.
>> >> >
>> >> > My thoughts shall follow later.
>> >>
>> >> OK, so here we go.
>> >>
>> >> I'm always a bit skeptical when it comes to speed tests - they're
>> really
>> >> laden with so many caveats that it's not funny. I took our new work
>> >> Starlink kit home in December to give it a try and the other day
>> finally
>> >> got around to set it up. It's on a roaming subscription because our
>> >> badly built-up campus really isn't ideal in terms of a clear view of
>> the
>> >> sky. Oh - and did I mention that I used the Starlink Ethernet adapter,
>> >> not the WiFi?
>> >>
>> >> Caveat 1: Location, location. I live in a place where the best Starlink
>> >> promises is about 1/3 in terms of data rate you can actually get from
>> >> fibre to the home at under half of Starlink's price. Read: There are
>> few
>> >> Starlink users around. I might be the only one in my suburb.
>> >>
>> >> Caveat 2: Auckland has three Starlink gateways close by: Clevedon
>> (which
>> >> is at a stretch daytrip cycling distance from here), Te Hana and
>> Puwera,
>> >> the most distant of the three and about 130 km away from me as the crow
>> >> flies. Read: My dishy can use any satellite that any of these three can
>> >> see, and then depending on where I put it and how much of the southern
>> >> sky it can see, maybe also the one in Hinds, 840 km away, although that
>> >> is obviously stretching it a bit. Either way, that's plenty of options
>> >> for my bits to travel without needing a lot of handovers. Why? Easy: If
>> >> your nearest teleport is close by, then the set of satellites that the
>> >> teleport can see and the set that you can see is almost the same, so
>> you
>> >> can essentially stick with the same satellite while it's in view for
>> you
>> >> because it'll also be in view for the teleport. Pretty much any bird
>> >> above you will do.
>> >>
>> >> And because I don't get a lot of competition from other users in my
>> area
>> >> vying for one of the few available satellites that can see both us and
>> >> the teleport, this is about as good as it gets at 37S latitude. If I'd
>> >> want it any better, I'd have to move a lot further south.
>> >>
>> >> It'd be interesting to hear from Jonathan what the availability of home
>> >> broadband is like in the Dallas area. I note that it's at a lower
>> >> latitude (33N) than Auckland, but the difference isn't huge. I notice
>> >> two teleports each about 160 km away, which is also not too bad. I also
>> >> note Starlink availability in the area is restricted at the moment -
>> >> oversubscribed? But if Jonathan gets good data rates, then that means
>> >> that competition for bird capacity can't be too bad - for whatever
>> reason.
>> >
>> > I'm in Southwest Oklahoma, but Dallas is the nearby Starlink gateway.
>> In cities, like Dallas, and Lawton where I live, there are good broadband
>> options. But there are also many people that live outside cities, and the
>> options are much worse. The low density userbase in rural Oklahoma and
>> Texas is probably ideal conditions for Starlink.
>> >>
>> >>
>> >> Caveat 3: Backhaul. There isn't just one queue between me and whatever
>> I
>> >> talk to in terms of my communications. Traceroute shows about 10 hops
>> >> between me and the University of Auckland via Starlink. That's 10
>> >> queues, not one. Many of them will have cross traffic. So it's a bit
>> >> hard to tell where our packets really get to wait or where they get
>> >> dropped. The insidious bit here is that a lot of them will be between 1
>> >> Gb/s and 10 Gb/s links, and with a bit of cross traffic, they can all
>> >> turn into bottlenecks. This isn't like a narrowband GEO link of a few
>> >> Mb/s where it's obvious where the dominant long latency bottleneck in
>> >> your TCP connection's path is. Read: It's pretty hard to tell whether a
>> >> drop in "speed" is due to a performance issue in the Starlink system or
>> >> somewhere between Starlink's systems and the target system.
>> >>
>> >> I see RTTs here between 20 ms and 250 ms, where the physical latency
>> >> should be under 15 ms. So there's clearly a bit of buffer here along
>> the
>> >> chain that occasionally fills up.
>> >>
>> >> Caveat 4: Handovers. Handover between birds and teleports is inevitably
>> >> associated with a change in RTT and in most cases also available
>> >> bandwidth. Plus your packets now arrive at a new queue on a new
>> >> satellite while your TCP is still trying to respond to whatever it
>> >> thought the queue on the previous bird was doing. Read: Whatever your
>> >> cwnd is immediately after a handover, it's probably not what it should
>> be.
>> >>
>> >> I ran a somewhat hamstrung (sky view restricted) set of four Ookla
>> >> speedtest.net tests each to five local servers. Average upload rate
>> was
>> >> 13 Mb/s, average down 75.5 Mb/s. Upload to the server of the ISP that
>> >> Starlink seems to be buying its local connectivity from (Vocus Group)
>> >> varied between 3.04 and 14.38 Mb/s, download between 23.33 and 52.22
>> >> Mb/s, with RTTs between 37 and 56 ms not correlating well to rates
>> >> observed. In fact, they were the ISP with consistently the worst rates.
>> >>
>> >> Another ISP (MyRepublic) scored between 11.81 and 21.81 Mb/s up and
>> >> between 106.5 and 183.8 Mb/s down, again with RTTs badly correlating
>> >> with rates. Average RTT was the same as for Vocus.
>> >>
>> >> Note the variation though: More or less a factor of two between highest
>> >> and lowest rates for each ISP. Did MyRepublic just get lucky in my
>> >> tests? Or is there something systematic behind this? Way too few tests
>> >> to tell.
>> >>
>> >> What these tests do is establish a ballpark.
>> >>
>> >> I'm currently repeating tests with dish placed on a trestle closer to
>> >> the heavens. This seems to have translated into fewer outages / ping
>> >> losses (around 1/4 of what I had yesterday with dishy on the ground on
>> >> my deck). Still good enough for a lengthy video Skype call with my
>> folks
>> >> in Germany, although they did comment about reduced video quality. But
>> >> maybe that was the lighting or the different background as I wasn't in
>> >> my usual spot with my laptop when I called them.
>> >
>> > Clear view of the sky is king for Starlink reliability. I've got my
>> dishy mounted on the back fence, looking up over an empty field, so it's
>> pretty much best-case scenario here.
>> >>
>> >>
>> >> --
>> >>
>> >> ****************************************************************
>> >> Dr. Ulrich Speidel
>> >>
>> >> School of Computer Science
>> >>
>> >> Room 303S.594 (City Campus)
>> >>
>> >> The University of Auckland
>> >> u.speidel@auckland.ac.nz
>> >> http://www.cs.auckland.ac.nz/~ulrich/
>> >> ****************************************************************
>> >>
>> >>
>> >>
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>> >
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>>
>>
>>
>> --
>> This song goes out to all the folk that thought Stadia would work:
>>
>> https://www.linkedin.com/posts/dtaht_the-mushroom-song-activity-6981366665607352320-FXtz
>> Dave Täht CEO, TekLibre, LLC
>>
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