[Starlink] insanely great waveform result for starlink

Fri Jan 13 12:41:34 EST 2023

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 at 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 at lists.bufferbloat.net> wrote:
> >
> >
> > On Fri, Jan 13, 2023 at 6:28 AM Ulrich Speidel via Starlink <
> starlink at 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 at 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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