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

I will have a look at tit. Seems similar to what we did in Teledesic in the
good old days :)

Marie-José Montpetit, Ph.D.
marie@mjmontpetit.com

From: tomaso.decola@dlr.de <tomaso.decola@dlr.de> <tomaso.decola@dlr.de>
Reply: tomaso.decola@dlr.de <tomaso.decola@dlr.de> <tomaso.decola@dlr.de>
Date: February 23, 2022 at 4:33:33 AM
To: ray@oneunified.net <ray@oneunified.net> <ray@oneunified.net>,
etosat@ietf.org <etosat@ietf.org> <etosat@ietf.org>
Subject:  Re: [EToSat] New Version Notification for
draft-lhan-problems-requirements-satellite-net-02.txt

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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