NASA DTN Protocol: How Interplanetary Internet Works 109
First time accepted submitter GinaSmith888 writes "This is a deep dive in the BP protocol Vint Cerf developed that is the heart of NASA's Delay-Tolerant Networking, better known as DTN. From the article: 'The big difference between BP and IP is that, while IP assumes a more or less smooth pathway for packets going from start to end point, BP allows for disconnections, glitches and other problems you see commonly in deep space, Younes said. Basically, a BP network — the one that will the Interplanetary Internet possible — moves data packets in bursts from node to node, so that it can check when the next node is available or up.'"
First post (Score:5, Funny)
The main problem is the long delay at light speed.
Re:First post (Score:5, Funny)
Holy shit! that just blows the crap out of that joke. All these years on Slashdot and the one time I try to do a first post joke I really get first post.
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Were you measuring light speed in American units instead of metric ones?
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Nah, I'm in Texas we use furlongs per fortnight.
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According to google:
the speed of light = 1802617500000 furlongs per fortnight
Though it may be less for you, since everything is bigger in texas (bigger furlongs = lower speed of light in fpf). Ive been wondering though, since everything is bigger in texas, does that mean everything is redshifted due to the wavelengths being longer?
As an Alaskan... (Score:1)
I fucking hate that saying.
Sarah Palin is our revenge for you assholes acting like we don't exist.
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I've always thought things got smaller in the cold.
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Yes, just look at an election map.
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it’s a protocol called Delay-Tolerant Networking, better known as DTN.
NASA’s experimental Disruption Tolerant Networking (DTN) protocol
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Trying to drag the quality of First Post comments up is always going to be a futile game. But thanks for trying.
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Having spent the last 3 weeks in the Galapagos, I can assure you there are long delays and dropouts even in tourist spots here at home(earth)... I do wish someone would implement some better protocol for those locations where speed and reliability aren't up to a reasonable standard. It would definitely help with satellite based ISPs in out of the way locations.. Having a system that would optimize the transaction(automatically send images, js, css despite not requesting it yet..) and automatically re-reques
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When all restaurants, hotels and internet cafes tested can't provide sufficiente quality to maintain a 2 second voice only skype call, it might be that just "upgrading your plan" might not be enough...
It doesn't always make sense to buy, and travel with, to third world countries, state-of-the-art satellite communication devices... (They are using non-state-of-the-art satellite and microwave systems and they aren't doing very well...)
They are hoping to get fiber-optic to the islands, but you can't just insta
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In the old days, we had exactly what you describe with regard to protocol optimization. A company I worked for used VSAT [wikipedia.org] comms to all their stores, and the VSAT hardware would spoof the IP and X-25 protocols on either earthbound end. What went over the sat link was a very optimized protocol tailored for the relatively long double hop delay.
X.25 with big buffers (Score:2)
TLDR X.25 with big buffers
Delays, delays (Score:5, Informative)
The problem is most any terrestrial network protocol expects a minimal signal-response delay between nodes, whereas even a perfectly functioning terabit/s Earth-Mars link would still have between a 6 and 40 minute delay due to the speed of light.
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The problem is most any terrestrial network protocol expects a minimal signal-response delay between nodes
RFC 1149 does not assume this, though the current implementation would have to be modified to avoid complete packet loss in a non-terrestrial environment - BF Skinner's work suggests one obvious adaptation:
http://tools.ietf.org/html/rfc1149 [ietf.org]
http://historywired.si.edu/object.cfm?ID=353 [si.edu]
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TFA does not describe how DTN/BP works. (Score:3)
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I generally prefer lmgtfy [lmgtfy.com] indirection, myself.
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it is a horrible article - regurgitates a press release without providing any details. Even the sole picture is not described.
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regurgitates a press release without providing any details
It even slavishly copies the typos "BP network â" the one that will the Interplanetary Internet possible".
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A couple places to start would be an explanation by NASA [nasa.gov] and the organisation for developing the protocols at the Delay Tolerant Networking Research Group [dtnrg.org].
UUCP (Score:3)
I thought something like this already existed. And it worked pretty well at the time.
http://en.wikipedia.org/wiki/UUCP [wikipedia.org]
More like fidonet (Score:5, Informative)
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mcvax!moskvax!kremvax!soyuz!ISS
after that I'm lost..
BP protocol? (Score:5, Funny)
The only problem with the BP protocol is the data mining rigs that burst and spread raw SQL queries all over the coast of Amazon.com and then wonder why people are pissed that they can't buy or sell from that site until its cleaned up!
"weâ(TM)ll get down and dirty... (Score:2)
...with the tech lower in the piece"
Except, they never do.
Didn't we have this figured out with FidoNet? (Score:5, Informative)
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AC is a C.
It worked with Fidonet. Store-and-forward is the viable way until we figure out FTL communication.
Repeater/router stations (Score:3)
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Re:Repeater/router stations (Score:4, Insightful)
Actually, the DSN model would work fine for a manned mission to Mars. You're never actually behind the Sun (well it might be possible, but it would be for less than a day). There is an issue where the Sun-Earth-Probe angle drops down to around 3-degrees (so, close to behind the sun), because of radio interference from the sun, but thats about a week long period that you could probably get away with. The biggest cause of comm issues at Mars is Mars itself. Fortunately, all orbiters have an Electra package that allows them to act as relays for each other and for surface assets.
Relay systems are actually more useful in the Earth-moon system at this point. A Lagrange point relay would be important for a far-side base on the moon, or a lander on that side. Earth orbit is where the biggest need for relays is, because the Earth is always in the way for LEO assets. Thats why we have TDRSS.
The biggest issue right now is simply the load on the DSN. Its underfunded and its hard to get enough time on it.
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Would this count as a start ? Artemis [wikipedia.org] (SKDR S/Ka band Data Relay).
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While on the subject, when are we going to establish repeater stations around the solar system so that space probes don't need massive transceivers and line-of-sight to communicate with the Earth?
IIRC, isn't that what the Mars orbiters are effectively doing for all the rover missions?
IP already delay tolerant? (Score:2)
Isn't IP already delay tolerant? I remember in the IPoAC trial for obvious reasons there were huge delays, but it still worked.
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Isn't IP already delay tolerant? I remember in the IPoAC trial for obvious reasons there were huge delays, but it still worked.
Ip over air canada? Yes certainly delays and rerouting.
Ip over avian carrier can cope with high delays and dramatic jitter, re-ordering and packet loss. I'm not sure udp/tcp can cope though, and Ip itself can't cope very well with a situation where the route only partially exists (say your orbiter acts as a router but is on the other side of the planet to your target lander, and needs to store the packets for a few hours)
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Isn't IP already delay tolerant? I remember in the IPoAC trial for obvious reasons there were huge delays, but it still worked.
Ip over air canada? Yes certainly delays and rerouting.
Ip over avian carrier can cope with high delays and dramatic jitter, re-ordering and packet loss. I'm not sure udp/tcp can cope though, and Ip itself can't cope very well with a situation where the route only partially exists (say your orbiter acts as a router but is on the other side of the planet to your target lander, and needs to store the packets for a few hours)
Actually he was talking about IPoverAnonymousCoward.
Or did you forget where you were?
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I am running a test: still waiting on a result:
ping -W 118000 voyager1.nasa.gov
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Isn't IP already delay tolerant? I remember in the IPoAC trial for obvious reasons there were huge delays, but it still worked.
Huge, yes - but not astronomically huge. The main failing of TCP/IP in extra-planetary usage is that RTT/delay measured in minutes smacks up against many-and-various timeouts in TCP. Effectively TCP thinks RTT of 16 minutes (eg to the sun and back) is actually 100% packet loss, because TCP gave up waiting (timeout) ages ago.
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Huge, yes - but not astronomically huge.
The delays were longer than 16 minutes... over an hour in most cases. There's the printing of the data, strapping it to the pigeon, scanning it back in, it all adds time.
I'm not sure if they increased timeouts to cope with the problem.
Linux (Score:2)
And now the question is: when will Linux support it?
Linux already supports it (Score:1)
ION is probably the most popular open source implementation of DTN, and was developed on Linux machines..
Re:Linux (Score:4, Informative)
> when will Linux support it?
Package: ion
Version: 3.0.1~dfsg1-1
Installed-Size: 2618
Maintainer: Leo Iannacone
Architecture: amd64
Depends: libion0 (= 3.0.1~dfsg1-1), libc6 (>= 2.7), libexpat1 (>= 2.0.1)
Suggests: ion-doc
Description-en: NASA implementation of Delay-Tolerant Networking (DTN)
Interplanetary Overlay Network (ION) software distribution
is an implementation of Delay-Tolerant Networking (DTN)
architecture as described in Internet RFC 4838.
.
This is a suite of communication protocol implementations designed
to support mission operation communications across an end-to-end
interplanetary network, which might include on-board (flight) subnets,
in-situ planetary or lunar networks, proximity links,
deep space links, and terrestrial internets.
.
Included in the ION software distribution are the following packages:
* ici (interplanetary communication infrastructure) a set of libraries
that provide flight-software-compatible support for functions on
which the other packages rely
* bp (bundle protocol), an implementation of the Delay-Tolerant
Networking (DTN) architecture's Bundle Protocol.
* dgr (datagram retransmission), a UDP reliability system that implements
congestion control and is designed for relatively high performance.
* ltp (licklider transmission protocol), a DTN convergence layer for reliable
transmission over links characterized by long or highly variable delay.
* ams - an implementation of the CCSDS Asynchronous Message Service.
* cfdp - a class-1 (Unacknowledged) implementation of the CCSDS File
Delivery Protocol.
.
This package contains the binary files.
Homepage: https://ion.ocp.ohiou.edu/ [ohiou.edu]
Subspace... (Score:2)
This is going ... (Score:2)
Moves the goal posts (Score:2)
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> if they are going to do remote robot control they are going
> to have to develop a very 'interesting' command structure. I
> can see it now... Go Forward... Stop... Oops!
NASA's robots are a bit more sophisiticated that that. It's closer to "Go over by the green rock" (not quite there yet, but close).
Layer3 UUCP (Score:1)
It sounds like a UUCP implemented at layer3.
The Ping! (Score:1)
Lego Mindstorms Robot (Score:1)
Does anyone have more information about the Lego Mindstorms robot that was used in this experiment? I'd like to use it as an inspiration with the kids.
The Curiosity Rover Made With Lego Mindstorms [wired.com] is pretty cool, but the fact that it uses "7 NXT Bricks, 13 NXT Motors, 2 Power Function Motors" makes it out of reach of the average home.
How Does DTN/BP Work? (Score:2)
Conceptually kinda sorta like email in that regard.
The BP side of the equation brings the concept of bundling more information together in one unit (unlike IP, which tends to break info into smaller units , eg fragmentation).
The plan being to bundle together all the information required for The Application to do the next thing.
Imagine sending all the html-and-javascripts-and-css for a webpage in one (huge) packet. Your browser would have enough to render the page and s
FIDO net reincarnate (Score:1)
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My layman's understanding is this:
Because entanglement does not transmit state between the entangled pairs. It only allows you to, after separation, determine the state of the remote node by reading the local one.
If you change the first node nothing is projected or expected to happen to the other in the pair.
Believe me, if they find a way to transmit information FTL in any method it would be plastered all over the papers, the internet, and Slashdot, and would call into question many parts of science as it i
Sounds like Packet Radio... (Score:2)
...something amateur ("ham") radio operators have been using since the 1980's...
-allen
KC2KLC
Usenet to the planets. (Score:2)
Forget all this talk of UUCP, Fido and normal packet protocols, the closest current similarity is sending binaries over usenet.
The most important part is the delay time, when you 'launch' a usenet message you won't receive anything at all from the remote end for a very long time. It will probably be long enough for you to transmit the entire message and then some.
The medium also has some limitations ...
Propagation delays on layer 2 (Score:2)
Old News (Score:2)
"Basically, a BP network — the one that will the Interplanetary Internet possible — moves data packets in bursts from node to node, so that it can check when the next node is available or up."
Err... didn't this used to be called FidoNet [wikipedia.org]?
Store and forward... (Score:1)
Sounds like the 'Net before TCP/IP (Score:2)
Remember modem connections and 'feeds' for news and email? When most links were offline most of the time? Yep, networking before 'up all the time' connections were available to most of the world.
I had a Linux (and before that a Mark Williams 'Coherent' UNIX like) computer that ran UUCP, and did dial on-demand connections. I had it download email and subscribed usenet 'news feeds' nightly from a local university that had 'free' connections for members of the local UNIX computer users group.
It worked. It
Re:Why are we wasting money on this? (Score:5, Insightful)
This is where you're completely wrong. Having a network infrastructure that extends outside of our planet (an extranet if I ever heard one!) is a requirement for being able to do things like set up bases and control robotic devices remotely. What we're doing is setting the groundwork for more than one user or group to both control and receive the telemetry from whatever mechanized device we send outside of our own atmosphere! This is huge!
Consider this: We send a basic construction rover and a 3D printer to Mars. Both are controlled by DTN/BP. We can send the 3D printer blueprints for parts and assembly instructions to the construction rover. That would allow us to build up an infrastructure before we even get there and monitor it by adding parts on an as-needed basis. It would allow us to do so cheaper as well, as things can be sent in smaller chunks, and some of it could be manufactured on the fly on site. Doing this using any of the older protocols or even proprietary mechanisms could make things much more complicated, especially if you decide to handover control or add members to a project you've already started.
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Better anticipate on the things you want to do on Mars, than to send over raw materials and a 3D printer, and think... "gosh, what shall we put together today?"
Re:Why are we wasting money on this? (Score:4, Insightful)
Better anticipate on the things you want to do on Mars, than to send over raw materials and a 3D printer, and think... "gosh, what shall we put together today?"
It's more like "gosh, what broke today?"
Assuming a 3D printer could work on Mars (no idea if that's possible), you could use it to greatly increase efficiency. Instead of sending over 2 or 3 of every possible item that might break or wear out, you could just send over 2 or 3 3D printers, and use them to replace broken tools as necessary. (Including, of course, worn-out 3D printers ;^))
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You are not thinking creative enough. You can have a 3D printer which of course can print spare parts for itself and have say a robot who can gather materials etc. Of course, the printer can print another 3D printer and another robots so we can infest the Mars in no time.
The only problem is that the printer which can print its own parts must be complicated and of course converting raw materials to printable ink is nigh impossible.
But in any case, imagine the possibilites! It isn't logically impossible, ther
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Well, the protocol could also be useful on earth, for example when there is a huge catastrophe. Besides, basically the whole Internet has been developed by government agencies at the expense of tax payer money. If the Internet had been developed by private industry, we'd all have $49.95/month AOL network access over modem that would provide about 8 network-capable applications with pay-per- use extra services.
Re:Why are we wasting money on this? (Score:5, Informative)
You mean the same way private industry invented the current internet protocols? Hint - they didn't. I think the point is while we don't have people out beyond the moon we do have an ever-increasing number of *machines* out there, every one of them equipped with a custom communication mechanism rendering them incapable of communicating with each other. If we work out a nice robust, standardized protocol now then not only do future probe developers (also mostly government funded) not need to spend time and money developing a new communication protocol, but future probes have the potential to intercommunicate with each other as well. One obvious application would be using "healthy" probes to act as relay stations for probes whose antennas or power supplies have degraded to the point that they no longer have the necessary gain to reliably communicate with Earth, but are otherwise operational. Or to route signals along clean signal paths where much lower transmission power is necessary - for example if a probe is in conjunction with Jupiter, the sun, or some other powerful radio source it is presumably much more difficult for Earth to receive a clean signal directly from it (or contrariwise if it was Earth in conjunction from the probe's perspective) Beyond that, who knows? Certainly few people envisioned most of the current uses of the internet when the protocols were being developed.
Oh, and we have plenty of mechanisms to get people past the moon, just getting into high orbit puts us half way to anywhere in the solar system, and it's actually easier to reach Earth's L3- and L4-point asteroid fields than it is to reach the Moon, we just haven't really had the motivation to do so yet. We could even get to Mars pretty easily with current technology if we wanted to, though arranging a return trip complicates things a little since we'd be down at the bottom of a gravity well again - i.e we'd need to either carry a staggering amount of extra fuel along, or establish a refueling base there. There'd be no shortage of volunteers for a one-way trip though, *especially* if the plan was to set up a sustainable base which would eventually (after years/decades) enable round trips to begin.
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What I've seen the Ayn Rand types want everything to be a meritocracy. The average engineer really only invents things on the scale of "years". The number of "landed & monied" inventors like Thomas Jefferson is considerably less than 1%. The average engineer has to have a "day job"... That means you invent what the boss is paying you for. For every engineer threatening to "go Galt" there ten more hungry, eager kids out of school that will do what the boss ASKS. It's is also the reason we don't have te
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Hmm, you must have been on a different Internet than I was. Do we remember when .com sites were considered poison and site admins refused to route traffic for them? Because they were profit-driven and diametrically opposed to the government-run version of the Internet? I do.
You could fill a book with communications protocols which never took off due to not being widely adopted. Indeed, many books of this type exist. You could even fill a book with communications protocols whose creators were vehemently
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I'll admit my early 'net history is rather shakey, but by that point hadn't the academics pretty much taken it over? It wasn't government-run much beyond the early proof-of-concept phase, and I don't recall commercial entities getting terribly involved until much later, some time after the Web was developed and started becoming popular. And sure, I know plenty of academics to this day that have no love for the commercial side of the internet. Nevertheless the commercial side eventually managed to flouris
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This is something for private industry to figure out. Why are our tax dollars being wasted on stuff like this when in reality, we have no mechanism to get men past the Moon for the next 20-30 years? Shouldn't we spend tax dollars on stuff that is useful, such as not being beholden to our #1 creditor, China?
We don't need Internet connectivity near Saturn, we need to fix a deficit problem right here on Earth.
Its saturnine enough here?
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This is something for private industry to figure out.
Private industry R&D looks 5-10 years down the road. A great nation will look 20, 50, and even 100 years down the road.
Why are our tax dollars being wasted on stuff like this
Wasting? This stuff is peanuts for the federal budget, and it probably even saves money (e.g, allowing different missions to use a common communication infrastructure).
we have no mechanism to get men past the Moon for the next 20-30 years
We put man on the moon with less than a decade's worth of work using 60's technology. If we were motivated, we could put men on mars within a decade too.
All of which is beside the point... we're sticking unmanned infra
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Shouldn't we spend tax dollars on stuff that is useful, such as not being beholden to our #1 creditor, China?
My, don't we sound talking-pointy.
http://finance.yahoo.com/news/biggest-holders-of-us-gov-t-debt.html [yahoo.com]
That’s right, the biggest single holder of U.S. government debt is inside the United States and includes the Federal Reserve system and other intragovernmental holdings.