IP over Lasers(mikekohn.net) |
IP over Lasers(mikekohn.net) |
https://github.com/mikeakohn/small_projects/blob/main/ip_ove...
I .... wonder if they considered just using PPP/SLIP?
But even then I don’t think I’d have thought to drag a dial-up framing protocol into a new project. Odds are I’d just recreate SLIP from muscle memory.... maybe?
Also this uses air as the medium.
The FDDI network comprised two fiber rings, one going clockwise and the other anticlockwise. If a host dropped off the network, the optical bypass switch would loop the two rings to each other, creating one big ring. Two non-adjacent hosts dropping off the network would break the ring.
The optical bypass was surprisingly simple. It was a couple of pieces of fiber segment glued to a swiveling magnet; an adjacent electromagnet pull the magnet/fiber assembly, connecting the network rings normally if energized. If power were removed from the electromagnet, a spring would pull it in the other direction, pointing the fibers into loop position, connecting the network rings in looped configuration.
In both cases, the air was the medium between the fibers entering the switch and the straight-through/loopback fiber segments.
Apologies in advance for my poor explanation.
Laser = over air, susceptible to interference like atmospheric things, dust, flies, also; since it's laser and over a distance, the photons will spread out. Beam divergence.
Fiber lines are carefully engineered to contain the light transmission to get it to where it has to go.
Microwave would be better than laser to my knowledge but then your packets are flying around through the air willy nilly. Things like SSL handshakes and unencrypted hello packets are readable.
But, anything lasers is amazing.
Eliminating crosstalk is the tough part and requires some modulation to ensure the transceiver isn't accidentally listening to itself via reflections or picking up interference.
Look up point to point laser links. They have been around for quite some time.
There's lots of commercial equipment in this space too.
That thing was awful.. lol.
The link was dead during
- Heavy rain
- Fog in the early morning
- While snowing for days
- Pigeons building a nest within the optics
Back then this was rocket science.
Basically, a filament flashlight is modified so that a magnetic coil was placed in series. An audio source is then fed through a second coil -- I can't remember the exact details of how this worked. The audio source was one of those fisher price sing-along tape players that I also modified I think. The tape was Abba.
On the other end, a cheapo solar cell was hooked up to a small kit amplifier and then you could hear the audio on a pair of headphones.
This was in 2002 ish, so fibre optics was a thing, but it was basically sci-fi for a scrappy kid in southern Africa. My whole spiel was how this was the precursor to fibre optics, and how one day all communications will be done using light in stead of electrons.
Fun times!
[1] - https://en.wikipedia.org/wiki/Photophone [2] - https://www.youtube.com/watch?v=SxlWrqioifg
1. Noise in the detection (the room is bright etc.)
2. The laser being a form that's not susceptible to direct modulation (if it takes a millisecond to start/stop lasing, obviously you cannot turn it on/off very fast)
It's shooting a laser through a fiber optic cable.
What problem are you trying to solve?
No mention of carrier pigeon? IPoAC has three RFCs!
Oh wait, didn't fermilab even use neutrinos in 2012? That seems even harder, practically made for an April fools RFC.
EBay has many models.
> Brashears also said Starlink’s laser system was able to connect two satellites over 5,400 kilometers (3,355 miles) apart. The link was so long “it cut down through the atmosphere, all the way down to 30 kilometers above the surface of the Earth,” he said, before the connection broke.
(the presentation that's being reported on, which I don't have access to: https://www.spiedigitallibrary.org/conference-proceedings-of... )
I'd call it a wash, space is hard, but so are atmospheric interactions, weather, foliage, and all the side effects of human habitation (like someone building a house in the middle of your laser link, yes that happens.)
Space is hard by many aspects, but on that part it's much easier than on earth.
Atmospheric scintillation is the barrier for free space laser communications on terra-firma; this is one reason we enclose the laser light in optical fibre to avoid this problem.
In space where nobody can hear you scream, scintillation isn't a problem.