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

From: David Fernández <[email-masked]>
Date: Wed, 23 Feb 2022 11:34:23 +0100

Dear all,

In Starlink, a traceroute command does not show the satellites, just
the gateway. I think that this is an indication that they are not
using IP routing protocols.

https://www.reddit.com/r/Starlink/comments/hbicej/maybe_dumb_question_what_will_we_see_on_traceroute

https://www.reddit.com/r/Starlink/comments/jo4fcu/traceroutemtr_anyone

https://www.reddit.com/r/Starlink/comments/mym6tt/puzzeling_trace_route

Has anybody tried traceroute on Iridium? OneWeb? Others?

Best regards,

David

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From: Marie-Jose Montpetit <[email-masked]>
Date: Wed, 23 Feb 2022 05:54:40 -0500

The 1st generation of Starlink satellites does not have any on-board
processing. So of course you will not see the satellites.

Even if they had on-board processing (to get intersatellite links) why
would they use IP routing outside of the ground network as they control the
who network?

mjm

Marie-José Montpetit, Ph.D.
[email-masked]

From: David Fernández <[email-masked]> <[email-masked]>
Reply: David Fernández <[email-masked]> <[email-masked]>
Date: February 23, 2022 at 5:34:36 AM
To: [email-masked] <[email-masked]> <[email-masked]>
Subject:  Re: [EToSat] New Version Notification for
draft-lhan-problems-requirements-satellite-net-02.txt

Dear all,

Best regards,

David

_______________________________________________
EToSat mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/etosat

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From: Arashmid Akhavain <[email-masked]>
Date: Wed, 23 Feb 2022 09:48:08 -0500

Very good point Marie-Jose! Satellite networks can be viewed as transport.
They can use other routing and addressing methods to move all sorts of
different payloads between ground stations. The ground stations of course
will need to take care of encapsulation and decapsulation.

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From: Marie-Jose Montpetit <[email-masked]>
Date: Wed, 23 Feb 2022 09:51:14 -0500

take care of encapsulation and decapsulation

It’s been the case for ages.

mjm

From: Arashmid Akhavain <[email-masked]>
<[email-masked]>
Reply: Arashmid Akhavain <[email-masked]>
<[email-masked]>
Date: February 23, 2022 at 9:48:20 AM
To: Marie-Jose Montpetit <[email-masked]> <[email-masked]>
Cc: [email-masked] <[email-masked]> <[email-masked]>, David Fernández
<[email-masked]> <[email-masked]>
Subject:  Re: [EToSat] New Version Notification for
draft-lhan-problems-requirements-satellite-net-02.txt

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From: Arashmid Akhavain <[email-masked]>
Date: Wed, 23 Feb 2022 09:54:04 -0500

If I am not mistaken, Iridium and OneWeb constellations are less than 1000
satellites in size. IP might be good enough for those constellations.

Best regards,
Arashmid

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From: Marie-Jose Montpetit <[email-masked]>
Date: Wed, 23 Feb 2022 09:57:47 -0500

Iridium?

This is from the 90s…

"IP good enough” - what do you mean? There are millions (billions) of nodes
on the internet.

Knowing the complexity of a satellite segment believe me you want to keep
the complexity on the ground :)

I think you guys need to do some research :)

mjm

From: Arashmid Akhavain <[email-masked]>
<[email-masked]>
Reply: Arashmid Akhavain <[email-masked]>
<[email-masked]>
Date: February 23, 2022 at 9:54:27 AM
To: David Fernández <[email-masked]> <[email-masked]>
Cc: [email-masked] <[email-masked]> <[email-masked]>
Subject:  Re: [EToSat] New Version Notification for
draft-lhan-problems-requirements-satellite-net-02.txt

Best regards,
Arashmid

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From: Arashmid Akhavain <[email-masked]>
Date: Wed, 23 Feb 2022 12:32:31 -0500

IP relies on address aggregation and topology abstraction to handle massive
scales. A link state protocol such as OSPF or ISIS also employs hierarchy
to handle scalability. An OSPF area for example rarely goes beyond 1000
nodes. There are several reasons for that, one of which of course is to
avoid broadcast storms arising from the link events.

A link state protocol with a single area covering an entire small-size
constellation (essentially a flat network with no hierarchy) would perhaps
be able to handle the link events (within the satellite network) and move
traffic between IP gateways on the ground (not necessarily equal to ground
stations) with a reasonable convergence time. However, I don't see how an
OSPF-like hierarchy can ever be configured and maintained in large
satellite networks. The movement alone will turn this into a daunting task.

Those of us with experience in building networking, routing, and forwarding
systems would never expose a large sum of routes to the satellite network
or any other inner network for that matter.
I am not sure what gave the impression that the complexity should be
placed anywhere else BUT the ground.

My point is that link state routing (doesn't mean IP) might work in small
constellations, but I don't think it will be able to handle routing and
forwarding in massive constellations. We should investigate alternatives to
existing terrestrial routing protocols to handle routing and forwarding in
satellite networks.

Trust me, I have been in networking/routing research over the past 30 years
and have built numerous systems that are actually deployed around the world
:)

On Wed, Feb 23, 2022 at 9:57 AM Marie-Jose Montpetit <[email-masked]>
wrote:

> Iridium?
>
> This is from the 90s…
>
> "IP good enough” - what do you mean? There are millions (billions) of
> nodes on the internet.
>