Just saw [this post](https://www.instagram.com/reel/CrivNA3LNel/?igshid=YmMyMTA2M2Y=) and I know it’s a very oversimplification, but what are these cables and what do they exactly do ? And who repairs, manages these cables.
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First of all, these cables do not provide internet to the entire world– what they do is provide connections across water. The vast majority of cabling is on land, either above ground or buried beneath it. Undersea cables are undersea because not every place is connected by land conveniently, so you just lay a cable underwater instead of underground, since there is no ground.
The cables are owned by various private companies, generally in telecommunications. Even Facebook and Google own some cables though now and are investing more into them. Their owners maintain them (generally through subcontractors).
We are also laying more and new cables all the time, there is a significant demand for this both to increase capacity in existing areas, such as US to Europe, or to add new capacity, such as to places in Africa
Well the original transoceanic telegraph cables were laid by the telegraph companies. Then later the phone companies. These used good old fashioned copper wires (originally just one or two) in a LOT of shielding, and then later simple repeaters or amplifiers (and the power to drive those).
Later on the cables switched from using copper conductors to fiber optic cables – the nice thing about fibre is you can shove multiple different color wavelengths of light down the same cable, so you can “multiplex” hundreds of different signals simultaneously. And with the right electronics to encode/decode and multiplex these light signals _very fast_ you get a single fiber optic strand carrying tens of gigabits per second of data. Now run _multiple_ fiber optic strands in the same cable == lots of bits / second.
Who runs and maintains them? The equipment, ships and personnel to make and lay and splice these cables across the ocean are ridiculously expensive – so there are only a few companies who specialize in doing this. These companies are contracted by the companies who want (and are willing to pay for) the cables. THOSE companies might be telco’s or governments or a consortium of telcos willing to “split” the cost. Big data companies too – Google is laying cables now.
But, to over simplify, you want a data cable from New York to Paris (or the closest beaches to)? You go to the cable making co and the switching gear maker and say “I want x channels over y fibres at z data rate” and they tell you what equipment they can make and what the cable will look like (how thick, how much can it bend, how frequent the repeaters have to be, what the max length of spool they can make – you can’t get a cable to go all the way, they have to make several and splice them together). Then you go to your cable laying company, give deets on the cable and they say yay or nay. Then you go and buy your landing points – literally where the cable comes ashore and connects to ground infrastructure. There’s gonna be a shack or a bunker with gear etc. and all the interconnects with your land infrastructure.
Then you fork over gobs of money, all the stuff gets made, the ship rolls up the spools of cable and they start at one side and start laying cable, splicing the segments together.
edit: then, once your cable is connected up how do you make money on it (unless you’re going to utilize all of its bandwidth yourself, like Google)? Well, you connect up your cable ends with switches and routers that connect to other lines for various other big telcos and you start charging them for bandwidth – you just saved them the $hassle$ of laying or contracting their own cable to get more bandwidth from A to B – they run a line to your ocean cable terminus, hook up the gear and you charge them by the Terrabyte. Or whatever, $10M/month.
First of all, these cables do not provide internet to the entire world– what they do is provide connections across water. The vast majority of cabling is on land, either above ground or buried beneath it. Undersea cables are undersea because not every place is connected by land conveniently, so you just lay a cable underwater instead of underground, since there is no ground.
The cables are owned by various private companies, generally in telecommunications. Even Facebook and Google own some cables though now and are investing more into them. Their owners maintain them (generally through subcontractors).
We are also laying more and new cables all the time, there is a significant demand for this both to increase capacity in existing areas, such as US to Europe, or to add new capacity, such as to places in Africa
Well the original transoceanic telegraph cables were laid by the telegraph companies. Then later the phone companies. These used good old fashioned copper wires (originally just one or two) in a LOT of shielding, and then later simple repeaters or amplifiers (and the power to drive those).
Later on the cables switched from using copper conductors to fiber optic cables – the nice thing about fibre is you can shove multiple different color wavelengths of light down the same cable, so you can “multiplex” hundreds of different signals simultaneously. And with the right electronics to encode/decode and multiplex these light signals _very fast_ you get a single fiber optic strand carrying tens of gigabits per second of data. Now run _multiple_ fiber optic strands in the same cable == lots of bits / second.
Who runs and maintains them? The equipment, ships and personnel to make and lay and splice these cables across the ocean are ridiculously expensive – so there are only a few companies who specialize in doing this. These companies are contracted by the companies who want (and are willing to pay for) the cables. THOSE companies might be telco’s or governments or a consortium of telcos willing to “split” the cost. Big data companies too – Google is laying cables now.
But, to over simplify, you want a data cable from New York to Paris (or the closest beaches to)? You go to the cable making co and the switching gear maker and say “I want x channels over y fibres at z data rate” and they tell you what equipment they can make and what the cable will look like (how thick, how much can it bend, how frequent the repeaters have to be, what the max length of spool they can make – you can’t get a cable to go all the way, they have to make several and splice them together). Then you go to your cable laying company, give deets on the cable and they say yay or nay. Then you go and buy your landing points – literally where the cable comes ashore and connects to ground infrastructure. There’s gonna be a shack or a bunker with gear etc. and all the interconnects with your land infrastructure.
Then you fork over gobs of money, all the stuff gets made, the ship rolls up the spools of cable and they start at one side and start laying cable, splicing the segments together.
edit: then, once your cable is connected up how do you make money on it (unless you’re going to utilize all of its bandwidth yourself, like Google)? Well, you connect up your cable ends with switches and routers that connect to other lines for various other big telcos and you start charging them for bandwidth – you just saved them the $hassle$ of laying or contracting their own cable to get more bandwidth from A to B – they run a line to your ocean cable terminus, hook up the gear and you charge them by the Terrabyte. Or whatever, $10M/month.
Others have answered your question, so here’s some more detail.
The vast majority of your traffic on the internet doesn’t travel very far. Website providers have set it up this way deliberately to improve your service. You get a faster response and better connection if the video file you are streaming on Youtube is on a server 100 miles away than if it’s 1,000 miles away. So they have built geographic distribution centers that service most internet traffic without having to communicate too far away. You have to really look around and almost be deliberate to generate traffic that will cross one of the cables in the ocean.
And it’s this way for most internet users in the developed world. I’m in the U.S. If I try to visit the website for the BBC (England) my request for their website is handled by a regional server in the U.S. that was set up by the BBC for that purpose. They send updates for the website to the U.S. server through the international cables, but the U.S. visitor traffic stays on land in America.
Others have answered your question, so here’s some more detail.
The vast majority of your traffic on the internet doesn’t travel very far. Website providers have set it up this way deliberately to improve your service. You get a faster response and better connection if the video file you are streaming on Youtube is on a server 100 miles away than if it’s 1,000 miles away. So they have built geographic distribution centers that service most internet traffic without having to communicate too far away. You have to really look around and almost be deliberate to generate traffic that will cross one of the cables in the ocean.
And it’s this way for most internet users in the developed world. I’m in the U.S. If I try to visit the website for the BBC (England) my request for their website is handled by a regional server in the U.S. that was set up by the BBC for that purpose. They send updates for the website to the U.S. server through the international cables, but the U.S. visitor traffic stays on land in America.
They don’t necessarily “provide” the internet, they’re just the highways internet traffic uses to travel on. So if you’re in India and log on to Facebook, it may pass through China and over the pacific via an undersea cable to facebook’s US servers, and then back. Keep in mind this is all happening at the speed light so traversing the planet doesn’t cause as many delays as you’d think.
Who owns them? Any sizable telecoms company (AT&T, Verizon, Tata, Orange, etc), big tech company (Microsoft, google, Facebook) and many governments at least share – if not downright own – some undersea cables. Many times they’re a collaboration between telecoms companies because they’re expensive. For instance, AT&T and China Telecom agree to build a cable from Shanghai to Los Angeles and split the costs and later, the traffic.
They don’t necessarily “provide” the internet, they’re just the highways internet traffic uses to travel on. So if you’re in India and log on to Facebook, it may pass through China and over the pacific via an undersea cable to facebook’s US servers, and then back. Keep in mind this is all happening at the speed light so traversing the planet doesn’t cause as many delays as you’d think.
Who owns them? Any sizable telecoms company (AT&T, Verizon, Tata, Orange, etc), big tech company (Microsoft, google, Facebook) and many governments at least share – if not downright own – some undersea cables. Many times they’re a collaboration between telecoms companies because they’re expensive. For instance, AT&T and China Telecom agree to build a cable from Shanghai to Los Angeles and split the costs and later, the traffic.
As of 2022, it’s almost 500 cables. Those cables are only direct connections from overseas country to overseas country. The connections *within* a country are numerous, and if two countries have land-based borders, it’s likely that there are multiple network connections across those borders. There are also satellite-based connections that aren’t mapped which tend to be slower. It’s all part part of making the internet resistant to damage (earthquakes, war, inadvertent backhoe use, etc.)
The latest map of the oversea cable network is here: [https://submarine-cable-map-2022.telegeography.com](https://submarine-cable-map-2022.telegeography.com)
Some of the connections are owned by governments. Others are owned by companies. There’s probably one or two that are owned by actual individuals. Management depends on how they “important” they are. There are government-owned mission critical connections that are either managed by that country’s civil defense forces or by independent contractors. The ones owned by companies are either managed by the company itself or farmed out to contractors. Usually it’s a mix. And the ones owned by individuals are likely maintained by whoever has the contract to maintain it.
The Internet is a network, those cables provide a communication between various services but they don’t necessary forward your traffic.
When you visit a website major parts of it (like the scripts and images) are served by CDN, a content distribution network, that is hosted somewhere close to you. You ask that server for the image on Reddit post and if it doesn’t have it stored then it calls the actual reddit server and gives it you. That way the image is transmitted only once over the transatlantic cable no matter how many people in your area view it. Only when you actually do some change like posting a comment it may be transmitted somewhere far away.
The big websites (like Facebook) are fragmented and keep their local stuff local so the selfies of your coworkers may be kept on servers in your city but when you want to check on your distant relative the images will be transmitted from far away.
The popular streaming services even keep their servers in your ISP so when you watch a popular movie it may be transmitted from somewhere down the street instead of somewhere further (but not far away, they also keep stuff on country level, national level and so on). That also means they will recommend you watch something that is popular in your area. The ISP and the streaming service are both happy because they have to pay less for the transfer costs.
In the days before https was on every website everyone could cache the websites. So even in very small communities like a dorm there could be a server set up to cache the content of popular websites. If a hundred students would check a popular news site every morning you could just make a one web request to it and then serve it locally to save bandwidth.
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