Re: [EToSat] New Version Notification for draft-lhan-problems-requirements-satellite-net-02.txt

Thanks Tomaso for the interesting pointer.

This kind of work is very useful when it comes to design routing strategies
for mega constellation systems.
If there are any public outputs of the SDN approach, I would be very
interested in having a look.

What I think would be also very interesting to discuss in terms of IETF
perspective is to assess whether existing routing mechanisms (OSPF,
SegmentRouting) require specific changes for the use case.

Nico

On Wed, Feb 23, 2022 at 10:33 AM <Tomaso.deCola@dlr.de> wrote:

> If of any interest or support to the discussion on routing for LEO,
> colleagues of mine at DLR published the following paper last year:
>
>
>
> Roth, M, Brandt, H, Bischl, H. Implementation of a geographical routing
> scheme for low Earth orbiting satellite constellations using intersatellite
> links. *Int J Satell Commun Network*. 2021; 39: 92– 107.
> https://doi.org/10.1002/sat.1361
>
>
>
> Then we are now working on SDN in space as enabler for new concepts of
> routing and network management, as part of an ESA-funded project.
>
>
>
> Best Regards,
>
>
>
> Tomaso de Cola
>
>
>
>
>
> ————————————————————————
>
> *Deutsches Zentrum für Luft- und Raumfahrt* (DLR)
> German Aerospace Center
> Institute of Communications and Navigation | Satellite Networks |
> Oberpfaffenhofen | 82234 Wessling | Germany
>
> *Tomaso de Cola, Ph.D.*
> Telefon +49 8153 28-2156 | Telefax  +49 8153 28-2844 |
> tomaso.decola@dlr.de <sandro.scalise@dlr.de>
> http://www.dlr.de/kn/institut/abteilungen/san
>
>
>
>
>
>
>
> *From:* EToSat <etosat-bounces@ietf.org> *On Behalf Of *Raymond Burkholder
> *Sent:* Mittwoch, 23. Februar 2022 04:07
> *To:* etosat@ietf.org
> *Subject:* Re: [EToSat] New Version Notification for
> draft-lhan-problems-requirements-satellite-net-02.txt
>
>
>
> On 2022-02-22 1:27 p.m., Arashmid Akhavain wrote:
>
> I agree that existing IP routing protocols can face convergence issues
> when it comes to satellite networks. IP and existing routing protocols rely
> on hierarchy to minimise the impact of link events. Establishing hierarchy
> in satellite networks can be very complex due to various movements
> especially when it comes to massive constellations.
>
>
>
> In polar constellations, the movement at the poles, and the seam plane
> will be problematic for existing routing protocols. The issue of course
> gets exacerbated in the Walker Delta constellation as the seam effect
> exists between every other orbit.
>
>
>
> A new method of routing might be required to address this issue. What are
> your plans w.r.t to this draft? Have you discussed some of these issues
> with any of the working groups?
>
> Using standard routing protocols are problematic as they are reactive.
> And due to inter-satellite delays, can take time to re-converge.  I was
> working with a company to come up with an SDN solution where we used TLE
> (Two Line Elements) to compute satellite nearness and then pre-populate
> neighbor entries for installation at pre-arranged times.
>
> In addition, to do this properly, these neighbor entries and routing table
> entries need to be populated based upon distributed path computation
> capabilities (due to the fact that the same ground stations are not always
> in view, and paths need to be adjusted as necessary).
>
>
>
>
> Best regards,
>
> Arashmid
>
>
>
>
>
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