Starlink routing

Masataka Ohta mohta at
Mon Jan 23 10:49:41 UTC 2023

Matthew Petach wrote:

> Unlike most terrestrial links, the distances between satellites are
> not fixed, and thus the latency between nodes is variable, making the
> concept of "Shortest Path First" calculation a much more dynamic and
> challenging one to keep current, as the latency along a path may be
> constantly changing as the satellite nodes move relative to each
> other, without any link state actually changing to trigger a new SPF
> calculation.

As LEO satellites should be leafs to a network of MEO satellites,
1 minutes of update period between MEO satellites should be enough,
which is not so dynamic.

Physical layer of MEO communications must (to save power and to
prevent broadcast storms) be point to point with known orbital
elements and link layer should be some point to point protocol
perhaps with ARQ.

As only meaningful metric between satellites is physical
distance, 16bit metric of OSPF should be enough.

The most annoying part is to have multiple ground stations,
which, as usual, makes the MEO network DFZ with more than 1M
routing table entries.

					Masataka Ohta

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