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

Thank you Tomaso,
I will have a look. Pure geographical routing works well when there is no
link down, but it faces issues when the link to the next closer node goes
down. I am interested to see whether the paper you mentioned addresses
those issues.

Best regards,
Arashmid

On Wed, Feb 23, 2022 at 4:33 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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