Re: LEO satellite use cases to be added for RFC2501

Hi Zeqil,

I think we need in this WG define/discuss the use cases for LEO which are
ad hoc networks, and I believe there are but not referenced by IETF yet,
therefore, I am working on it. more comments below,

> The subject below was: Routing in emerging LEO satellites
On Wed, Nov 8, 2023 at 11:27 AM [email protected] <
[email protected]> wrote:

> Hi Henning:
>
> Thanks for the reply. It a good question : )
>
> In an idea world, satellites should work in their orbits in plan and have
> predictable trajectory (as well as the connectivity).
>
> But something might change in the merging LEO satellite networks.
>
> First, satellite movements are somehow "predictable", but are not so
> "deterministic" as we may expect.
>
> The outer space is a very complex environments. Due to the lower altitude,
> satellites are affected by the gravity, and satellites have to continuously
> adjust their orbit altitude and position during the orbiting time. Just
> like self-driving cars, satellites have to monitor debris nearby and
> accordingly locally adjust their orbits to avoid unexpected conficts.
>

Agree,


>
> In addition, there are a range of unexpected factors such as radio
> interference, solar storm, channel fading, bad weather conditions, etc,
> that could change the inter-connectivity and link quality for
> inter-satellite and ground-satellite communications.
>
> Second, even though we exclude these "unexpected" factors, it is still
> very chanllenging to pre-calculate all possible any-to-any routes on a
> global scale.
>
> Note that emerging LEO constellations like Starlink and Kuiper have
> thousands of LEO satellites. And the entire network topology changes
> frequently and endlessly (sometimes it changes in tens of seconds!). If we
> try to pre-calculate all routes for all topology snapshots, there should be
> a significantly large number of possible routes, for every any-to-any
> communication pair, and in every time slot! Pre-caching all possible
> routing tables on each satellite could not be doable for
> resource-constrained satellites.
>

I don't think those two implementations are doing IP routing, so will need
your confirmation on that,


> So the new things here are globe-wide LEO dynamics (predictable and
> unexpected), 3D network topology (when integrating LEO satellites into
> terrestrial Internet), and significantly increase in the constellation
> sizes.
>

Yes that is mentioned in 3GPP documents, we need to find solution that work
within our WG charter,


>
> That is why we say that it is challenging to make a scalable and robust
> routing for the emerging LSNs. And we believe there should be many new
> problems and questions : )
>

I agree, and thanks, I hope we can discuss more on these use cases of LEO
and their applicability for our new wg_documents/charter

Regards
AB

 On Wed, Nov 8, 2023 at 8:48 AM [email protected]

> <[email protected]> wrote:
> >
> > Hi all MANET:
> >
> > Thanks for the nice talks in IETF 118. As a new attendee, I learnt a lot.
> >
> > I am currently an assistant professor at Tsinghua University, and our
> group are working on the internetworking technologies in the upcoming LEO
> satellite networks (LSN).
> >
> > One important direction of our research is exploring how to achieve
> scalable and robust routing in LSNs. And we have many recent efforts in
> this direction. Some have been published in the research conference of
> computer networks.
> >
> > Here are some of our recent research works:
> >
>
>

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