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

[Marie-Jose Montpetit <[e-mail]>]

Where do you intend to present at 113?

Marie-José Montpetit, Ph.D.
[e-mail]



From: Lin Han <[e-mail]> <[e-mail]>
Reply: Lin Han <[e-mail]> <[e-mail]>
Date: February 23, 2022 at 5:15:16 PM
To: Arashmid Akhavain <[e-mail]>
<[e-mail]>, Nicolas Kuhn <[e-mail]>
<[e-mail]>
Cc: [e-mail] <[e-mail]> <[e-mail]>,
[e-mail] <[e-mail]> <[e-mail]>,
[e-mail] <[e-mail]> <[e-mail]>
Subject:  Re: [EToSat] New Version Notification for
draft-lhan-problems-requirements-satellite-net-02.txt

Good question. Actually this has been studied by 3gpp. 3gpp has proposed
the Satellite-based NG-RAN architectures in TR38.821. In this architecture,
satellite network is an infrastructure for 5G. In its proposed
“Regenerative payload” mode, satellite network (with ISL) should provide
the IP connectivity for wireless access and NTN integration. Different SP
is able to use satellite as wireless access network. From this expectation,
satellite network will be access and backhaul network for wireless, the
standardized protocol/methods are expected.

I will have a slide in the next IETF meeting to explain more details about
the problems.



Regards



Lin



*From:* Arashmid Akhavain <[e-mail]>
*Sent:* Wednesday, February 23, 2022 12:36 PM
*To:* Nicolas Kuhn <[e-mail]>
*Cc:* [e-mail]; [e-mail]; [e-mail]
*Subject:* Re: [EToSat] New Version Notification for
draft-lhan-problems-requirements-satellite-net-02.txt



That could be another alternative.

The question that I have been struggling with is whether and how satellite
networks can benefit from standardisations. These networks are proprietary
(at least for the time being). It is difficult to imagine satellites in a
multi-vendor ecosystem.



That's why I asked what the authors of this draft intended to do.



Arashmid



On Wed, Feb 23, 2022 at 3:12 PM Nicolas Kuhn <[e-mail]>
wrote:

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 <[e-mail]> 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 [phone] | Telefax  [phone] | [e-mail]
<[e-mail]>
http://www.dlr.de/kn/institut/abteilungen/san







*From:* EToSat <[e-mail]> *On Behalf Of *Raymond Burkholder
*Sent:* Mittwoch, 23. Februar 2022 04:07
*To:* [e-mail]
*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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