[Starlink] some details on the DTN, bundle protocol, and a capacity question

[Vint Cerf]

I haven't pushed to much further until we get some real data from running
implementations. I also hope we can develop a simulator from which we might
derive measurements to compare with actual data and modeled (queueing
theoretic) data.

v


On Sat, Dec 11, 2021 at 9:58 PM Dave Taht <dave.taht at gmail.com> wrote:

> A good deep dive into DTN with vint cerf is here:
>
> https://www.datacenterdynamics.com/en/analysis/vint-cerfs-interplanetary-ambitions/
>
>  I went looking for existing source code for it, some here:
> https://projet.liris.cnrs.fr/riot/dtn_implementations_survey.html
>
> From the interview...
>
> Q: "So for store and forward to work, what is the level of storage
> each node needs to the speed of the network?"
>
> VC: That's such a good question. So guess what, I have the same
> question. And I said, 'Okay, where do I go to get an answer to that?'
> And that is the capacity question: What capacity of this DTN network,
> given if I know where the nodes are, and I know what the physics are.
> And I know what the data rates could be. I have a traffic matrix. Do I
> have a network which is capable of supporting the demand?
>
> That's the formulation of the question you're asking. So I went to the
> best possible source for this question, Leonard Kleinrock at UCLA. He
> is the father of the use of queueing theory to analyze store and
> forward networks way back in 1961/62, doing his dissertation at MIT on
> this topic, not in aid of the interplanetary network, but more general
> question on store and forward networking.
>
> And so he did some fantastic work, he broke the back of the problem
> with what was called the independence principle. But he left MIT and
> came to UCLA in the '60s, he was on my thesis committee. And he's
> still very, very active. He's 87, still blasting on.
>
> So I sent him a note saying, look, here's the problem. I've got this
> collection of notes, and I've got a traffic matrix, and I have this
> DTN environment, how do I calculate the capacity of the system so I
> know, I'm not gonna overwhelm it.
>
> And, you know, I figured it would take him a while and maybe find a
> graduate student. So *two days later*, I get back two pages of dense
> math saying, okay, here's how you formulate this problem. Now, I
> didn't get all of the answer. I still don't have all of the answer.
> But I know I have one of the best minds in the business looking at the
> problem."
>
> That was back in august of this year, made any progress?
>
> --
> I tried to build a better future, a few times:
> https://wayforward.archive.org/?site=https%3A%2F%2Fwww.icei.org
>
> Dave Täht CEO, TekLibre, LLC
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>


-- 
Please send any postal/overnight deliveries to:
Vint Cerf
1435 Woodhurst Blvd
McLean, VA 22102
703-448-0965

until further notice
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