Re: [Starlink] thinking about the laser links again

[Michael Richardson <mcr@sandelman.ca>]

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Ulrich Speidel <ulrich@cs.auckland.ac.nz> wrote:
    > IP forwarding (as opposed to routing) checks the destination IP address
    > against a set of routes in your routing table, which are essentially
    > destination networks identified by network IP address and netmask. That
    > decides which interface the routers forwards out through (i.e., to which
    > neighbour). At a local level, one can often supply these routes manually as
    > static routes, but at a global level, it still takes the likes of BGP to help
    > with routing, chiefly because the Internet doesn't have a tree structure at
    > the global level.

This is not an accurate view.
You have mixed interior gateways with external gateways.

For external traffic Starlink just needs to pick the right exit node, it
doesn't need to know about the global BGP infrastructure.  IPv6 makes this
much simpler (order fewer of networks), so I'd put all my v4 traffic as a
service and/or NAT64.

    > Things that change for you if you are a Starlink satellite:

    > - Cells you can service (and therefore hosts attached to Dishys you can
    > reach). You may be over Brazil now, the Atlantic next, then over the UK, and
    > then over Germany, and so on... So your on-board routing table would need to
    > reflect that. You never spend more than a minutes or so over the same
    > cell.

Yes, you need a complete internal routing view.
This is probably more complex and dealing with the exterior view.

    > network need to know that they need to send traffic to that destination to
    > us. I say "something like BGP" here as the network is proprietary, so doesn't
    > have to stick to any open standards.

The problem is akin to routing in a large DC, with VMs that migrate from
cabinet to cabinet on a regular basis.  Only faster.  And way more
predicatable.

If I had old silicon, I'd do it with two stacks of MPLS.
If I had newer silicon, then SRv6.
Both cases, with a bunch of PCEs spread around the planet.
I'd love to make the satellites independant of earth support, but that could
be version 3.

--
]               Never tell me the odds!                 | ipv6 mesh networks [
]   Michael Richardson, Sandelman Software Works        |    IoT architect   [
]     mcr@sandelman.ca  http://www.sandelman.ca/        |   ruby on rails    [


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