Starlink has bufferbloat. Bad.
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From: Ulrich Speidel <ulrich@cs.auckland.ac.nz>
To: David Lang <david@lang.hm>
Cc: starlink@lists.bufferbloat.net
Subject: Re: [Starlink] speedtest.net takes a look at sat internet around the globe
Date: Fri, 13 Aug 2021 15:45:40 +1200	[thread overview]
Message-ID: <aa2bab9c-a588-798a-b6e5-dde5f069b6ad@cs.auckland.ac.nz> (raw)
In-Reply-To: <nycvar.QRO.7.76.6.2108121903160.1653956@qynat-yncgbc>

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>
> > Indeed. But there is more to this than that. Basically, each satellite
> > in an inclined orbit crosses each parallel (latitude) up to its
> > inclination twice per orbit. Since there is a lot less length of
> > parallel at higher-numbered latitudes, parallels with latitudes close
> > the the inclination get more satellite crossings per mile of parallel
> > per hour. So more rockets isn't going to change the density disparity
> > unless their satellites will go into orbits with vastly different
> > inclinations (which I hope they will).
>
> the first shell is all the same inclination, but they have launched 
> enough to
> get full coverage even down to the equator. later shells are going to 
> be a
> different inclination.

I'm quite aware of this, but Starlink have changed their orbital 
configuration repeatedly over the life of the project thus far. But 
having a satellite within range is only one half of the connection. That 
satellite also needs to be able to link you to something.

And so there won't be full coverage around the tropics for a while as 
most Starlink birds at this point in time aren't equipped with laser 
interconnects. They currently work bent pipe only, which means being 
within a few hundred km of a teleport or no connectivity at all. Many 
remote Pacific islands are further than that away from the nearest other 
piece of land, let alone a Starlink teleport.

But yeah, the plans are noted. I'd add to that that longish zig-zagging 
laser forwarding paths pose the question of latency, too, so it'll be 
interesting how that will play out.

>
> see the wikipedia page on starlink for the description of the 
> different shells
> https://en.wikipedia.org/wiki/Starlink#Constellation_design_and_status 
> <https://en.wikipedia.org/wiki/Starlink#Constellation_design_and_status>. 
> phase 1
> is ~4200 satellites (they've launched ~1700), phase 2 is an additional 
> ~7500 at
> a lower altitude, and they've talked about wanting a phase 3 that 
> would take the
> total count of over 40,000 satellites.

Taken as read a long time ago ;-)

-- 

****************************************************************
Dr. Ulrich Speidel

School of Computer Science

Room 303S.594 (City Campus)
Ph: (+64-9)-373-7599 ext. 85282

The University of Auckland
ulrich@cs.auckland.ac.nz
http://www.cs.auckland.ac.nz/~ulrich/
****************************************************************




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  reply	other threads:[~2021-08-13  3:45 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-12 21:22 Darrell Budic
2021-08-12 22:34 ` Ulrich Speidel
2021-08-12 23:24   ` Ricky Mok
2021-08-13  1:55     ` Ulrich Speidel
2021-08-13  2:10       ` David Lang
2021-08-13  3:45         ` Ulrich Speidel [this message]
2021-08-13  3:57           ` David Lang
2021-08-15 15:47     ` Darrell Budic
2021-08-13  1:54   ` David Lang
2021-08-13  4:51     ` Ulrich Speidel

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