I don't know why, but I would have expected higher speeds. Maybe my mind just assumes "lasers = fast". It would be interesting to know which factors make this setup unreliable at higher speeds.
IP over Lasers
31–40 of 83 posts
Re: IP over Lasers
#32We had a laser link to the university 20 years ago. 10MBit/s for 300 people.
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
Re: IP over Lasers
#33Re: IP over Lasers
#34We had a laser link to the university 20 years ago. 10MBit/s for 300 people. 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
There are many long-range WiFi solutions. I wonder how these would have performed as alternatives.
Re: IP over Lasers
#35Re: IP over Lasers
#36Earlier quoted context omitted.
Doesn't Starlink do that already for sat2sat comms?
Not quite the same thing as doing it in an atmosphere.
There's not a huge amount of info I've seen on the specifics of Starlink's LISL setup, but there are a couple interesting bits in here: https://www.pcmag.com/news/starlinks-laser-system-is-beaming...
> 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... )
Re: IP over Lasers
#37They 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.
SLIP is old and mostly forgotten for sure, but PPP was almost universal in dialup and unfortunately common in DSL. PPPoE was the bane of my existence as someone who had to support third-party routers on DSL. PPTP was also very common for small VPNs even well past when it should have been retired due to insecurity because it worked out of the box on Windows and Mac without a third party client.
Re: IP over Lasers
#38Re: IP over Lasers
#39We had a laser link to the university 20 years ago. 10MBit/s for 300 people. 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
There are many long-range WiFi solutions. I wonder how these would have performed as alternatives. https://en.wikipedia.org/wiki/Long-range_Wi-Fi
Nowadays you just can buy pair of cheap Mikrotik oder Ubiquiti directional dishes.
Back then this was rocket science.
Re: IP over Lasers
#40Aren'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)
Yeah, but kinda cool making it from scratch. Also this uses air as the medium.
About 25-30 years ago we had an FDDI network, and the hosts had optical bypass switches on them.
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.