[Starlink] fiber IXPs in space

Mon Apr 17 16:37:29 EDT 2023

On Tue, 18 Apr 2023, Ulrich Speidel via Starlink wrote:

> For all I can tell, dishy only uses one satellite at a time and so routing 
> via dishys to other satellites - while certainly an attractive concept - 
> doesn't seem to be happening.

the one doesn't prevent the other, if two dishys are talking to the same 
sateelite, or if the satellites relay the data via lasers, the dishies could 
talk without a ground station involved while only talking to one satellite.

> Most modern comms systems - look at your phone - run pretty complicated 
> stacks these days, and I'd be very surprised if Starlink didn't. That makes 
> it likely that there is an extra network and transport layer between dishy 
> and gateway (a term, which I'm incidentally not using for the WiFi router 
> that comes with dishy but for the gateways that connect the Starlink space 
> network to the terrestrial Internet). Any routing between dishy, satellite 
> and gateway (and any lasers along the way) will therefore be happening at 
> that extra network layer - the transport layer above it has the job to make 
> the path between dishy and gateway look like a single data link layer hop. 
> This is why you don't see a satellite IP in your traceroute. Quite how that 
> extra network and transport layer is implemented is something that probably 
> only Starlink knows. The power of layered communication ;-)

Elon Musk has said that dishy-to-dishy communications is a capability that they 
are working towards.

They have also talked about how going NY to London would be faster via starlink 
space relay than via undersea fiber (the gain in speed from light in a vaccum vs 
in a fiber more than makes up for the extra distances involved), but since I 
haven't heard of them doing this yet, I don't think it's possible yet.

I would not be surprised to learn that starlink establishes a preferred gateway 
and creates a virtual circuit to it that can be routed through various 
satellites (it seems like the easiest thing to do, and works well initially)

But I believe that they are working to improve this to meet their stated goals, 
and when they have the ability to send over multiple virtual circuits, or do 
true dynamic routing, it would be straightforward for the dishy to notice that 
the destination is a supported anycast address and handle it differently.

As a side note, I think that anything you try to serve via satellites will need 
to be anycast friendly, just to handle the fact that it will need to be served 
from multiple satellites so that you can get it from one close to you as opposed 
to needing to be relayed to the other side of the earth at times.

>
> P.S.: I'll apologise in advance for upcoming silence over the next few days - 
> we're taking Dishy for an outing to get it away from the Clevedon gateway, so 
> we can finally get Dave some more data ;-)

I just had SpaceX replace my 1st gen dishy with a 2nd gen one, after I do some 
validation, I will move one of them to the mobile plan and be able to test it at 
different places (I'm equipping a van so that it can be a mobile office and will 
test it by driving a ways and trying to work from the van in some odd locations) 
Probably won't get finished until after July.

David Lang

> On 18/04/2023 7:09 am, David Lang via Starlink wrote:
>> if Starlink can route via in-space-lasers and in a dishy-to-dishy way (both 
>> have
>> been talked about, at least in future tenses) then they could also route to 
>> an
>> on-satellite IP.
>> 
>> historically 'bent pipe' satellite support meant that the satellite just
>> repeated the RF signal back down with no modifications. Starlink was 
>> designed to
>> do routing of traffic, some to a ground station (possibly more than one), 
>> some
>> to other satellites (including ones at different altitudes), and some to 
>> other
>> dishys. It's initial deployment included no routing, just relaying between 
>> a
>> dishy and a ground station, but we know that it's extended beyond that, at 
>> least
>> when there are not ground stations in range
>> 
>> David Lang
>> 
>> On Mon, 17 Apr 2023, David Fernández via Starlink wrote:
>> 
>> > Well, I have some concerns about how you implement an anycast address
>> > in a transparent satellite.
>> >
>> > If the pre-requisite for this is that the satellite is a router, I
>> > don't see this happening anytime soon. I am not aware of any system,
>> > not deployed, even designed with satellites being routers, but IRIS2
>> > could be the first, maybe:
>> > 
>> https://defence-industry-space.ec.europa.eu/eu-space-policy/eu-space-programme/iriss_en 
>> <https://defence-industry-space.ec.europa.eu/eu-space-policy/eu-space-programme/iriss_en>
>> >
>> > Bufferbloat will be checked and prevented as much as possible in IRIS2.
>> >
>> > Regards,
>> >
>> > David
>> >
>> > 2023-04-17 16:38 GMT+02:00, Rodney W. Grimes 
>> <starlink at gndrsh.dnsmgr.net>:
>> >>> On Sun, 16 Apr 2023, David Fern?ndez via Starlink wrote:
>> >>>
>> >>> > The idea would be that the satellite inspects IP packets and when it
>> >>> > detects a DNS query, instead of forwarding the packet to ground
>> >>> > station, it just answers back to the sender of the query.
>> >>>
>> >>> This would be a bad way to implement it. You don't want to override
>> >>> queries to
>> >>> other DNS servers, but it would be very easy to create an anycast 
>> address
>> >>> that
>> >>> is served by the satellites.
>> >>
>> >> Yes, and the later is what I proposed, the idea of intercepting
>> >> someone ELSE'S anycast address and processing it would be
>> >> wrong in many ways, in effect a Man In the Middle attack
>> >> as stated else where.
>> >>
>> >>> David Lang
>> >> --
>> >> Rod Grimes
>> >> rgrimes at freebsd.org
>> >>
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