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The Dunant subsea cable

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Re: The Dunant subsea cable

#141

Post by sneak »

ksec wrote: post #52

I 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…

I agree, but we can start on our local machines first. Most of the latency of modern computers isn't related to the network.

Re: The Dunant subsea cable

#142

Post by rorykoehler »

idlewords wrote: post #58
ksec wrote: post #52

I 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.

How deep would this bore tunnel be at the centre most point if it was perfectly straight? Would it go into the mantle?

Re: The Dunant subsea cable

#143

Post by [deleted] »

BelenusMordred wrote: post #130
idlewords wrote: post #58

Earlier 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.

[deleted]

Re: The Dunant subsea cable

#144

Post by squigg »

lifeisstillgood wrote: post #107

Old timer story - years ago, Demon Internet (my old employer) was beginning to enter super-growth and wanted to really set itself up for trans-atlantic connections. So they decided to buy a T1 - 45Mbps link across the atlantic. Now it turns out that BT had only ever resold fractions of T1s - they had never actually had anyone want a whole one. And as such their sales commissions did not cap out. So, we rang up, a sal…

As a Future Sound of London fan, I was so proud to be an early Demon dial-up customer when they name-checked their email address on Demon on their ground-breaking ISDN radio transmission on Radio 1. (To be read in a monotone female delivery) "For further information, please access the following code ... F S O L .. ACK ... F S O L ... DEMON ... CO ... UK"

Good times - they were a wonderful company, thank you

Re: The Dunant subsea cable

#145

Post by lostlogin »

jlund-molfese wrote: post #133
nippoo wrote: post #119

This is super-cool! I found "enough to transmit the entire digitized Library of Congress three times every second" to be a really weird comparison though - I'm used to text being really small and compressible, and I doubt many people have an intuitive grasp of how much One Scanned Library of Congress is. How many hour-long Netflix/YouTube episodes per second, on the other hand...

I agree, but somehow a LoC became a well-established unit of measuring data transfer[1]. So maybe less-technical readers are used to hearing that comparison. 1 - https://blogs.loc.gov/thesignal/2012/04/a-library-of-congres...

This can join the others - Olympic swimming pool, football fields, London bus, Empire State Building.

Re: The Dunant subsea cable

#146

Post by sp332 »

crispyambulance wrote: post #104
DoomHotel wrote: post #98

Earlier quoted context omitted.

You can send spatially-separated signals down a single multi-mode fiber. https://www.nature.com/articles/s41598-019-53530-6

That's interesting! But multimode fiber isn't feasible for thousands of kilometers? This is transatlantic. Wouldn't that have to be singlemode just for the distances involved?

Even single-mode needs repeaters along the length of the cable to get across an ocean. I guess you could use multimode and a lot more repeaters, but that seems more expensive and more failure-prone.

Re: The Dunant subsea cable

#148

Post by aynyc »

iptrans wrote: post #137
aynyc wrote: post #117

Earlier quoted context omitted.

> Assuming the underwater cable itself is 10 times as expensive as regular cable, its about $150 million for 9000 km. Looking at what I can find, it looks like way more than 10 times the cost. https://i.imgur.com/7Dm7EEp.jpg

10x is a fair estimate of cost vs regular armored fiber cable. Source: I've laid subsea cable.

Just to be sure, you mean 10x between subsea cable and regular armored fiber cable, not cat6 I can get from best buy.

Re: The Dunant subsea cable

#149

Post by tzs »

aynyc wrote: post #117
tzs wrote: post #92

Earlier quoted context omitted.

It's probably cheaper than people would expect because the long run across the deep ocean is a lot more straightforward than most people would expect. 1. For the deep ocean parts of the route, cables and associated equipment (such as repeaters) are simply spooled out from the back of the cable laying ship, to settle on the ocean floor. 2. For shallow waters, the cable is buried. This is done by dragging a plow along…

> Assuming the underwater cable itself is 10 times as expensive as regular cable, its about $150 million for 9000 km. Looking at what I can find, it looks like way more than 10 times the cost. https://i.imgur.com/7Dm7EEp.jpg

My estimate came to around $22k/kilometer for the cable itself plus the laying it in deep ocean. I didn't estimate the costs of repeaters.

The Google project was $33k/kilometer, so I don't think I could have been too far off on the cable itself. Looking at other undersea fiber projects, that seem about typical. For example, this one [2] estimated $27k/kilometer [1].

Here's an Alibaba seller with submarine fiber for $2000-9000/kilometer [2].

The submarine cables have an aluminum or copper tube around the fiber optics, an aluminum water barrier, and a sheath of stranded steel wires, and an outer polyetylene layer, with various other layers of mylar, polycarbonate, and petroleum jelly in between.

I'd expect the metal layers to be the most expensive parts. Looking at the cost of tubes or cables of those materials, it looks like each of those would be in the $1000-2000/kilometer range.

[1] http://infrastructureafrica.opendataforafrica.org/ettzplb/co...

[2] https://www.alibaba.com/product-detail/Submarine-Fiber-Optic...

Re: The Dunant subsea cable

#150

Post by [deleted] »

idlewords wrote: post #58
ksec wrote: post #52

I 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.

[deleted]
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