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The Dunant subsea cable

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Re: The Dunant subsea cable

#81

Post by crispyambulance »

The article says this cable uses SDM (space division multiplexing). Which, for fiberoptics, means that you have multiple fibers. Of course they HAVE TO put many wavelengths on each fiber, each wavelength carrying a signal.

The "state-of-the-art" AFAIK is to use many wavelengths per fiber, each one carrying ~192 wavelengths each wavelength transporting at up to 100Gbps (this is known as DWDM).

So so with SDM, you just have more fibers? So what? It seems like I am missing something here? Why is "SDM" the key concept rather than "DWDM"? Why not just say DWDM with 12 fiber pairs?

Re: The Dunant subsea cable

#84

Post by Cthulhu_ »

dna_polymerase wrote: post #79
throw0101a wrote: post #64

Earlier quoted context omitted.

Especially the linked blog post, as it doesn't render unless you allow JavaScript from gweb-cloudblog-publish.appspot.com (per uMatrix). Webdevs: is there a reason why a page would be designed so that JS being on is mandatory? Especially for something as prosaic as a couple of paragraphs of text.

Ever heard of React, Vue or Angular? If you meant mandatory in terms of the actual medium requiring it, I can only hint to interactive applications, aside from that I don't think it would actually be mandatory.

All of those can be rendered server-side if needs be, and in my experience, can actually lead to a superior browsing experience compared to plain server-side served HTML. But it has to be done right.

Gatsby + Netlify with a CMS-as-a-service like Contentful or Prismic will lead you to a good result. We made e.g. https://fox-it.com/ using that, its back-end is Wordpress but it's drained empty to rebuild the website. Note how it works without JS, the dropdowns don't work but they fall back to full page navigation page. Note how with JS enabled, all the content shows up instantly. This is how it's supposed to be done.

Re: The Dunant subsea cable

#85

Post by Cerium »

sparsely wrote: post #16
tyingq wrote: post #12

Earlier quoted context omitted.

"What is the cost of doing something like this?" Their Oregon to Japan cable, 9000km and laid in 2016, cost $300M. https://www.computerworld.com/article/2939316/googles-60tbps...

That is at least 1 order of magnitude cheaper than I would have guessed. Mind boggling that it's cheaper to do that then buy like the 4th best meal delivery app in Canada or whatever.

Indeed, California spent 20 times as much for a 3.5km bridge.

Re: The Dunant subsea cable

#86

Post by jeffbee »

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.

Heh baby steps maybe? The existing cables aren’t even short paths along great circles. The Oregon-Japan cable google owns is 12000 km along a 7500-km path.

Re: The Dunant subsea cable

#87

Post by [deleted] »

markphip wrote: post #31

I know there are many of these cables that have been around for years, but I am curious how are they physically secured? Especially where they transit from ocean to land? Is there some long underground/sea tunnel of conduit that the cable is routed through to the basement of some building? Or if you are walking along the beach somewhere is there just some cable running out of the ocean along the beach to some buildin…

[deleted]

Re: The Dunant subsea cable

#90

Post by andreasley »

m3kw9 wrote: post #51

“ enough to transmit the entire digitized Library of Congress three times every second” the engineer in me: compressed? With images? Or just raw texts?

From 2016: "THE LOC’S DIGITAL COLLECTION currently comprises over 7 petabytes (7 million gigs) with more than 15 million items, including 150,000 print books. In an ideal future scenario, the LOC estimates that it could digitize a further 3-5 PB a year" [1]

So only the raw texts, probably. 10TB sounds about right for that.

[1] https://nplusonemag.com/online-only/online-only/the-library-...

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