How interesting. (Surprised this didn't come up in IoT domain.)
NASA's DTN: https://www.nasa.gov/directorates/heo/scan/engineering/techn...
& there is something called Space Packet Protocol: https://public.ccsds.org/Pubs/133x0b2e1.pdf
The APID in that spec (88 bits) is where a lot of complexity (imo) is pushed up to the application layer and seems key to the archicture. It looks like basically a typed-data+endpoints addressing scheme and assigned to endpoints per mission by that mission itself.
The term may not be commonly used there, but like everything in tech, people often try to solve the same problems from different angles using different terms. Offline First is also roughly comparable to DTN and some people in the IPFS have framed it in the context of Offline First.
DTN can actually solve some of the most pressing communications issues we face today: 40% of the world population is permanently disconnected from the Internet, and many of those who are are subject to severe censorship (look up #KeepItOn).
NASA’s HDTN [1] says it is based on IETF RFC 5050 [2]. Have to read that to understand privacy and censorship implications, specially the Bundle Security Protocol [3]. But just skimming the indexes in those indexes reinforces my impression that this architecture can lockdown/lockout at administrative points.
[1]: https://github.com/nasa/HDTN
[2]: https://datatracker.ietf.org/doc/rfc5050/
[3]: https://datatracker.ietf.org/doc/html/rfc6257
—- from RFC 6257 —-
The stressed environment of the underlying networks over which the Bundle Protocol will operate makes it important for the DTN to be protected from unauthorized use, and this stressed environment poses unique challenges for the mechanisms needed to secure the Bundle Protocol.
Furthermore, DTNs may very likely be deployed in environments where a portion of the network might become compromised, posing the usual security challenges related to confidentiality, integrity, and availability.
Same here.
This is going to come across as a shameless plug, but implementing DTN tech is actually my full-time job and we've got a couple of projects that will address some of the issues you identified:
- Awala, a computer network where compatible apps can use the 'standard' Internet infrastructure when it's available, or fall back to a backup medium that tolerates delays of up to 6 months. https://awala.network/ - VeraId, an offline authentication protocol powered by DNSSEC. https://veraid.net/
Delay/Disruption Tolerant Networking is an attempt at some of this to actually make an interplanetary protocol. Delayed routing protocols appear to be super hard -- not to mention the problem with issues with MITM attacks at the relays.
There's also interesting aspects of the space application of DTN where transmitters needing to have knowledge of solar system orbits (including the relays) to broadcast at the right time so the message will arrive when the relay is on the right side of Mars, say.
It's looks like LunaNet is going to be the solution for the Artemis mission. But the moon is only 1.3 light seconds away, so not really a super hard challenge (except when trying to transmit to the side opposite the earth). Heck, TCP will probably still work through purely analog relays, albeit terribly.
But I'm more interested in what happens for Mars missions when the round trip time is going to be measured in minutes.