we have the most experience with the ION version of BPv7 v On Sun, Dec 12, 2021 at 7:06 PM Dave Taht wrote: > On Sat, Dec 11, 2021 at 7:15 PM Vint Cerf wrote: > > > > 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. > > I am just going to ignore the way this thread went for now. What I was > mostly asking was what version of dtn was the most promising for an > embedded (e.g. cerowrt II) implementation? > > https://dtn7.github.io/ looks very promising, especially the rust > bits. Rust lets me sleep better and we are moving some support for it > into openwrt's next release. > > https://github.com/morgenroth/ibrdtn is undermaintained but was > already ported to openwrt, and is lighter weight. There's another one > targetted at microcontrollers ( https://upcn.eu/ ), but not the FRAM > one we used on a previous space-related project... really liked those > FRAMs.... > > As for the simulator side, what/where are the requirements? I confess > to wanting to feed forward the asterank, or celestia, or nasa's new > https://eyes.nasa.gov/apps/asteroids/#/asteroids into it another 10 > years and plunk 28k nodes into it.... > > > > > > > v > > > > > > On Sat, Dec 11, 2021 at 9:58 PM Dave Taht 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 > >> _______________________________________________ > >> Starlink mailing list > >> Starlink@lists.bufferbloat.net > >> https://lists.bufferbloat.net/listinfo/starlink > > > > > > > > -- > > Please send any postal/overnight deliveries to: > > Vint Cerf > > 1435 Woodhurst Blvd > > McLean, VA 22102 > > 703-448-0965 <(703)%20448-0965> > > > > until further notice > > > > > > > > > -- > 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 > -- Please send any postal/overnight deliveries to: Vint Cerf 1435 Woodhurst Blvd McLean, VA 22102 703-448-0965 until further notice