Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

IP over Lasers

mikekohn.net

Post reply on HN
Print view View original

11–20 of 83 posts

Re: IP over Lasers

#11

Post by vpShane »

tgma wrote: post #2

Aren't regular fiber-optics just mass-deployed IP over lasers? (this message is brought to you by at least one, likely multiple, lasers in prod)

Yes and no, worth reading in to. Yes in the sense of, technically laser but gets reconverted along the path in many ways, ethernet turning it in to frames after a receiver (modem, whatever equipment) then translates it.

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.

Re: IP over Lasers

#12

Post by toast0 »

Back when 10M ethernet was popular, it was pretty easy to wire up something like this with the transceiver (AUI) port... wire the tx to a laser and the rx to a photodiode (or whatever), ???, profit.

There's lots of commercial equipment in this space too.

Re: IP over Lasers

#14

Post by MisterTea »

The AT tiny is not needed at all. You have a digital signal coming right out of the serial cable which can drive the laser using a buffer and a Schmitt trigger on the receiver.

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.

Re: IP over Lasers

#15

Post by tgma »

jonah-archive wrote: post #9
advisedwang wrote: post #3

Earlier quoted context omitted.

Yeah, but kinda cool making it from scratch. Also this uses air as the medium.

Free-space optical transmission is a thing, though it's environmentally quite challenging. We tested some gear from https://www.koruza.net at the Internet Archive ~10 years ago or so (I've also built some 10G point-to-point links in my garage, though I'd hardly call them reliable). It is pretty cool to see a scratch build rather than using commercial transceivers

Doesn't Starlink do that already for sat2sat comms?

Re: IP over Lasers

#17

Post by eqvinox »

toast0 wrote: post #12

Back when 10M ethernet was popular, it was pretty easy to wire up something like this with the transceiver (AUI) port... wire the tx to a laser and the rx to a photodiode (or whatever), ???, profit. There's lots of commercial equipment in this space too.

https://ronja.twibright.com/

Re: IP over Lasers

#18

Post by eqvinox »

tgma wrote: post #15
jonah-archive wrote: post #9

Earlier quoted context omitted.

Free-space optical transmission is a thing, though it's environmentally quite challenging. We tested some gear from https://www.koruza.net at the Internet Archive ~10 years ago or so (I've also built some 10G point-to-point links in my garage, though I'd hardly call them reliable). It is pretty cool to see a scratch build rather than using commercial transceivers

Doesn't Starlink do that already for sat2sat comms?

Not quite the same thing as doing it in an atmosphere.

Re: IP over Lasers

#19

Post by Retr0id »

jasonjayr wrote: post #10

They built a program they called (relay) that sends packets between a tun network device & a uart serial device https://github.com/mikeakohn/small_projects/blob/main/ip_ove... I .... wonder if they considered just using PPP/SLIP?

A while back I was doing some IP-over-UART shenanigans and it took me a surprising amount of research to discover the existence of SLIP. I think it's one of those things that at some point "everyone knew about" and ended up being poorly documented as a result.
Post reply on HN