Earlier quoted context omitted.
Remember: You want your photons crispy around the edges, not charred.
I take my photons medium-rare.
Medium-rare with a light salad
The Dunant subsea cable
201–210 of 262 posts
Re: The Dunant subsea cable
#202I see a lot of these fiber lines pop up on tiny islands throughout the pacific. What’s happening at these places? Are there people who work there and if so what are they doing?
Tax evasion, err 'financial optimisation'.
Re: The Dunant subsea cable
#203I'm delighted by all the speculation in this thread about whether the cable laid by the global surveillance company is somehow being spied on.
Well we assume any important Internet choke-point is used for surveillance. If I just started surveilling anything sent en clair my first stop would be Internet backbone connections.
Re: The Dunant subsea cable
#204Earlier quoted context omitted.
This was done in the 70s/80s, but I doubt it's worth the effort now. It only worked because the Soviets assumed the cables were inaccessible. End-to-end encryption is a thing even for the general public now. Now we just compromise the servers/routers. https://gizmodo.com/the-nsa-actually-intercepted-packages-to...
> I doubt it's worth the effort now It's very much still happening. Metadata is enough for intel purposes, storage is ridiculously cheap and post-quantum breaks of key exchange is forever 20 years away like fusion. https://www.nytimes.com/2015/10/26/world/europe/russian-pres... https://www.theatlantic.com/international/archive/2013/07/th... https://www.zdnet.com/article/spy-agency-taps-into-undersea-...
You're not gonna get any useful metadata out of it since the entire pipe is encrypted/decrypted at each end. All you'd see from tapping it at the middle is an unbelievably vast stream of random ones and zeros, the encrypted version of all commingled traffic.
Re: The Dunant subsea cable
#205Earlier quoted context omitted.
T1 maximum speed 1.544 Mbps T3 is about ~45 Mbps Reference: https://en.wikipedia.org/wiki/T-carrier
And it was probably an E3 (Uk/Europe is E1/E3, US/JP is T1/T3)
E3 is ~34Mbps, so it probably wasn't. It's true that the E1/E2/E3 hierarchy is used outside the US, but links to the US can be either depending on carrier preference.
The T1/T2/T3 and E1/E2/E3 hierarchies join at the STM-1 level: An STM-1 can be subdivided as 4 x E3s or 3 x T3s.
This means that on a EUUS SDH link, an STM-1 can be demuxed into either E3s or T3s, so you can have both standards on the same fiber.
Re: The Dunant subsea cable
#206Earlier quoted context omitted.
My bet is on tech like Starlink with inter-satellite communication. Starlink should have lower latency with space lasers compared to fiber.
OP is talking about photonic bandgap fiber I think, or perhaps another kind of photonic-crystal fiber. At any rate, whereas in regular fiber guiding light via differences in refractive index the speed of light is only about 70% c, photonic bandgap fiber can reach something like 99.7% c, which is close enough to c in vacuum as to essentially eliminate the difference vs a free space EM link (particularly for space-base…
Now...
How do you splice a hollow optic fibre?
Re: The Dunant subsea cable
#207Earlier quoted context omitted.
You gotta bore for that sweet latency win. A chord tunnel between San Francisco and Hong Kong would save 1300 miles (20% improvement right there), and if you drill it straight enough, you won't even need a cable.
Please don't give the HFT's ideas, they'll probably do it and cause a half dozen tsunamis in the process.
...and create a supervolcano.
Re: The Dunant subsea cable
#208Earlier quoted context omitted.
Starlink satellites are in orbit 550km high. So any journey would add at least 1100km. Moreover not sure that a single satellite would be able to hit another one across transpacific distances and may need to go through multiple hops to get there. Each hop will add latency since signal needs regeneration. So it’s not clear to me a swarm of satellites is a real winner from a latency POV. Furthermore, given costs to put…
Are you sure about the necessary regeneration? Let me hand wave from the dark skies here for a moment: 1.) Think of the precision mirrors in the so often mentioned EUV-lithography equipment from ASML for latest generation chips from TSMC. 2.) Now imagine something like that on board of a satellite, maybe smaller. 3.) Have 2.) moveable with sufficient precision to bounce the rays from satellite to satellite in realtim…
Those 'precision EUV mirrors' achieve a reflectance of about 70% i.e. they aborb ~30% of the EUV light that reaches them. :)
More seriously, those mirrors are special because they use bragg reflectors to handle 13.5nm light. They're not special for their precision, nor their reflectance.
Setting that aside, the major problem with your proposal is that laser still have significant bream spreading. So the mirrors would need to be large enough to encompass a spread beam at every step, which adds weight and volume for both the mirror and the tracking mechanism. The tracking mechanism is particularly problematic because moving mass on a satellite affect the attitude, so you either need precision counterweights to null it out, or large reaction wheels.
Using MEMS mirrors instead would solve some of the mass issues, but MEMS mirrors have very limited tracking (typically limited to a single axis) which would probably render them impractical.
Far, far easier to just send and receive the signal at every step.
Re: The Dunant subsea cable
#209This cable is not just to be used by Google right? Or am I misunderstanding something? Fundamentally, infrastructure should be publicly owned and then rented by companies to use it, in this case it seems like Google physically owns the cables and infrastructure which would be a massive waste.
Why is it a waste? If Google has enough demand to fill the cable, then how is it waste?
(And I assume that Google has enough demand: If it didn't, why would they build such a large cable?)
Re: The Dunant subsea cable
#210I know a lot is focusing on the Bandwidth. But are we making any progress on Long Distance Subsea Cable using Hollow Core Cable, achieving close to maximum speed of light for theoretical lowest latency possible? Imagine cutting latency from West Coast US to Hong Kong by 50ms! Light is only traveling at around 2/3 of speed within Fibre. The previous decades have been around Bandwidth. Is time we shift out focus to lat…
You gotta bore for that sweet latency win. A chord tunnel between San Francisco and Hong Kong would save 1300 miles (20% improvement right there), and if you drill it straight enough, you won't even need a cable.
> if you drill it straight enough, you won't even need a cable.
Well, yes and no. I recall they wanted to pursue hollow cables in the early days of optical cabling, but it turned out solid fiber was the answer.
(sorry, can't find a good reference)
So FTTC (Fiber Through The Core) is what you want.