You are currently viewing The Secret Lifetime of the five hundred+ Cables That Run the Web

The Secret Lifetime of the five hundred+ Cables That Run the Web

The live performance is in London. You are watching it reside from your private home in Atlanta. What makes that doable is a community of subsea cables draped throughout the chilly, darkish contours of the ocean flooring, transmitting sights and sounds on the velocity of sunshine by bundles of glass fiber as skinny as your hair however hundreds of miles lengthy.

These cables, solely about as thick as a backyard hose, are high-tech marvels. The quickest, the newly accomplished transatlantic cable referred to as Amitié and funded by Meta, Microsoft and others, can carry 400 terabits of information per second. That is 400,000 occasions sooner than your private home broadband for those who’re fortunate sufficient to have high-end gigabit service.

And but subsea cables are low-tech, too, coated in tar and unspooled by ships using mainly the identical course of used within the 1850s to put the first transatlantic telegraph cable. SubCom, a subsea-cable maker primarily based in New Jersey, advanced from a rope producer with a manufacturing facility subsequent to a deep-water port for simple loading onto ships.

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Although satellite tv for pc hyperlinks have gotten extra necessary with orbiting methods like SpaceX’s Starlink, subsea cables are the workhorses of world commerce and communications, carrying greater than 99% of visitors between continents. TeleGeography, an analyst agency that tracks the enterprise, is aware of of 552 present and deliberate subsea cables, and extra are on the way in which because the web spreads to each a part of the globe and each nook of our lives.

You most likely know that tech giants like Meta, Microsoft, Amazon and Google run the brains of the web. They’re referred to as “hyperscalers” for working lots of of information facilities filled with hundreds of thousands of servers. You won’t know that in addition they more and more run the web’s nervous system, too.

“The entire community of undersea cables is the lifeblood of the financial system,” mentioned Alan Mauldin, an analyst with TeleGeography. “It is how we’re sending emails and cellphone calls and YouTube movies and monetary transactions.”

Two thirds of visitors comes from the hyperscalers, in accordance with consulting agency McKinsey. And the info calls for of hyperscalers’ subsea cable is surging 45% to 60% per 12 months, mentioned SubCom Chief Government David Coughlan. “Their underlying progress is pretty spectacular,” he mentioned.

Hyperscalers’ information calls for are pushed not simply by their very own content material wants, like Instagram photographs and YouTube movies considered world wide. These firms additionally typically function the cloud computing companies, like Amazon Net Companies and Microsoft Azure, that underlie hundreds of thousands of companies’ international operations.

“Because the world’s starvation for content material continues to extend, it’s essential to have the infrastructure in place to have the ability to serve that,” mentioned Brian Quigley, who oversees Google’s subsea and terrestrial networks.

The primary subsea cables spanned main communication routes like London to New York. These stay important, however newer routes are bringing bandwidth far off the crushed observe: the west coast of Greenland, the volcanic island of St. Helena west of Africa, the southern tip of Chile, Pacific island nations, the 8,000-person city of Sitka, Alaska.

It is all a part of a gradual transformation of subsea communications. The place as soon as cables have been the exception, linking a number of high-priority city facilities, now they’re turning into a world-spanning mesh. In different phrases, subsea cables are coming to resemble the remainder of the web, regardless of excessive prices and unique know-how.


However as extra web visitors traverses subsea cables, there’s additionally purpose to fret about them. The explosive sabotage final 12 months of the Nordstream 1 and a couple of pure fuel pipelines connecting Russia and Europe was far more logistically tough than chopping an web cable the thickness of your thumb. An ally of Russian chief Vladimir Putin mentioned subsea cables are honest recreation for assault. Taiwan has 27 subsea cable connections that the Chinese language army might see as tempting targets in an assault.

Learn extra: House Web Cheat Sheet: Low cost Plans, High Suppliers and A lot Extra

The dangers are vivid: Vietnam’s web efficiency suffered because of outages on all 5 of its cables for months earlier this 12 months, and the volcanic explosion on the island of Tonga severed it from most communications for weeks.

However these dangers are dwarfed by the very actual advantages, from the macroeconomic to the purely private. The community is rising extra dependable and succesful with sooner speeds and a surge in new cables extending the community past at the moment’s 870,000 miles of routes, and that’ll coax increasingly more nations to hitch.

That makes the web richer and extra resilient for all of us — together with you getting work achieved and discovering leisure after the workday’s over.

Why subsea cables are spreading

The financial benefits are appreciable. Subsea cable hyperlinks imply sooner web speeds, decrease costs, a 3% to 4% increase in employment and a 5% to 7% increase to financial exercise, McKinsey estimates.

On the identical time that hyperscalers’ visitors calls for have been surging, the telecommunications firms that historically put in subsea cables pulled again from the market.

Workers connect a SubCom cable, buoyed by orange floats, from a cable-laying ship in the distance to a landing site on a beach.

A SubCom cable undergoes set up, between the cable-laying ship within the distance and a touchdown web site on the seashore. Later, the orange floats can be eliminated and the cable buried so it is not seen.


“Roughly 10 years in the past, a variety of the normal telco suppliers began to actually deal with wi-fi and what was taking place inside their last-mile networks,” mentioned Frank Ray, who leads hyperscale community connectivity for Microsoft’s Azure cloud computing enterprise. The wait for brand new cables grew longer, with the planning section alone stretching to 3 to 5 years. The hyperscalers wanted to take management.

Hyperscalers initially started with investments in others’ initiatives, a pure transfer on condition that subsea cables are sometimes operated by consortia of many allies. More and more, hyperscalers now construct their very own.

The end result: an enormous cable buildout. TeleGeography, which tracks subsea cables carefully, initiatives $10 billion can be spent on new subsea cables from 2023 to 2025 world wide. Google-owned cables already constructed embrace Curie, Dunant, Equiano, Firmina and Grace Hopper, and two transpacific cables are coming, too: Topaz this 12 months and, with AT&T and different companions, TPU in 2025

Such cables do not come low-cost: A transatlantic cable prices about $250 million to $300 million to put in, Mauldin mentioned.

The cables are important. If one Azure area fails, information facilities in one other area come on-line to make sure clients’ information and providers maintain buzzing. Within the US and Europe, terrestrial cables shoulder a lot of the load, however in Southeast Asia, subsea cables dominate, Ray mentioned.

With the hyperscalers in cost, pushing information as a substitute of voice calls, subsea networks needed to turn into far more dependable. It could be a minor irritation to get a busy sign or dropped name, however interruptions to laptop providers are far more disruptive. “If that drops, you lose your thoughts,” Coughlin mentioned. “The networks we make at the moment are dramatically higher than what we made 10 years in the past.”

The variety of subsea web cables has surged. By 2025, a complete of 552 must be operational.

Information: TeleGeography; graphic: Viva Tung/CNET

Subsea communications: The origin story

Immediately’s cables ship as much as 250 terabits per second of information, however their know-how dates again to the 1800s when scientists and engineers like Werner Siemens found out how you can lay telegraph cables underneath rivers, the English Channel and the Mediterranean Sea. Lots of the early cables failed, partially as a result of the load of a cable being laid on the underside of the ocean would rip the cable in two. The first transatlantic cable challenge that succeeded operated for under three months in 1858 earlier than failing and will solely ship simply over one phrase per minute.

However buyers wanting to money in on speedy communications underwrote the event of higher know-how. Larger copper purity improved sign transmission, stronger sheathing decreased cable breaks, repeaters put in periodically alongside the cable boosted sign power and polyethylene insulation changed the sooner rubberlike materials harvested from gutta-percha bushes.

Phone calls finally changed telegraph messages, pushing know-how additional. A transatlantic cable put in in 1973 might deal with 1,800 simultaneous conversations. In 1988, AT&T put in the primary transatlantic cable to make use of glass fiber optic strands as a substitute of copper wires, an innovation that boosted capability to 40,000 simultaneous cellphone calls.

A subsea internet cable, sliced to show a cross section of its fiber optic lines for data transfer, steel cabling for strength, copper for power distribution and plastic for insulation and protection.

A subsea web cable from producer SubCom exhibits, from the middle outward, its optical fibers for information switch, metal cabling for power, copper for energy distribution and plastic for electrical insulation and safety.

Stephen Shankland/CNET

SubCom’s subsea cable manufacturing facility dates again to its rope-making roots within the 1800s. “Most rope in that point was used on ships or wanted to be transported by ships,” CEO Coughlan mentioned. “A manufacturing facility on a deep port, with fast entry to the ocean and with winding capabilities, is what was wanted to rework into the phone cable enterprise.”

How subsea cables work

Fiber optic traces transmit information as pulses of laser gentle. As with terrestrial fiber optic traces, utilizing a number of frequencies of sunshine — colours, to you and me — means extra information could be despatched directly. Community tools ashore at both finish of a cable encodes information into the sunshine for transmission and decodes it after it is obtained.

Fiber optics are nice for long-haul information transmission, however they’ve their limits. That is why there is a huge bulge within the cable each 30 to 60 miles referred to as a repeater, to spice up the sign power.

Repeaters require energy, although, and that is the place one other a part of the cable development comes into play. Exterior the fiber optic strands, a copper layer carries electrical energy at as much as 18,000 volts. That is sufficient to energy repeaters all the way in which throughout the Pacific Ocean simply from one finish of the cable, although energy sometimes is on the market from each ends for higher reliability. 

Why not increase the facility of the lasers as a substitute, so you do not want repeaters as typically? Since you’d soften the cables, mentioned Brian Lavallée, a senior director at networking know-how large Ciena.

Learn extra: Sure, the Web Connection Sort Makes a Distinction. This is Why

His firm makes the community tools at both finish of the subsea cables, using completely different information encoding strategies — manipulating gentle waves’ frequency, section and amplitude — to squeeze as a lot information as doable onto every fiber.

“We have been in a position to get very, very near the Shannon restrict, which is the utmost quantity of data you may ship down a communication medium,” Lavallée mentioned.

How subsea cables are put in

Corporations putting in a cable begin by selecting a route, surveying the path to dodge marine issues like nature preserves, tough seafloor and different cables. When a number of nations, telecommunications companies and companies are concerned, discovering an agreeable route and acquiring permits could be very complicated.

SubCom's Responder cable-laying ship floats on a blue ocean.

That is SubCom’s Responder. Contained in the subsea cable-laying ship are three giant “tanks” that may maintain 5,000-ton coils of cable.


The cables themselves are step by step paid out from specialised ships. That is not so simple as unspooling your string while you’re flying a kite on a windy day.

Fiber optic strands are slim, however subsea cables are thicker, heavier and bulkier. They’re saved in metallic cylinders that wind and unwind the cables as they’re moved from shore to ship or from ship to ship. A single ship’s three “tanks” can maintain 5,000 tons of cable, which works out to about 1,800 miles of light-weight cable and 600 miles of cable that is been armored for busy waters.

SubCom has to determine the set up order for every cable section and make it possible for when set up begins, the suitable finish of the cable is on the high of the coil. Which means earlier than loading onto the ship, whereas the cable is saved at SubCom’s depot, it should be saved “flipped” the opposite means up. It reverses route to the right configuration because it’s transferred loop by loop onto the ship, SubCom’s Coughlan mentioned.

That is already difficult, however climate, permits or different issues can drive modifications to the set up order. That may require flipping a cable at sea with two ships facet by facet. In a really digital enterprise it seems to be a really analog drawback attempting to account for components just like the ships lurching on the open ocean and the cable’s weight and bending limits.

“Now we have one man particularly that is only a savant at this,” Coughlan mentioned. “He has to have the ability to resolve it along with his hand with string first, as a result of we discovered the pc modeling by no means works.”

Learn extra: Finest Web Suppliers for 2023

Close to shore, cables are armored with metal cable and buried within the sea flooring with a particular plow towed behind the ship. The plow pulls up into the water any time the brand new cable crosses one other that is already put in. Within the deeper ocean, the place fishing tools and anchors aren’t an issue, the cable has much less safety and is solely laid on the underside of the ocean flooring.

Subsea cable cuts and fixes

Subsea cables are fairly powerful, however each three days or so, one will get lower, TeleGeography mentioned. The first culprits, accounting for about 85% of cuts, are fishing tools and anchors. Ships typically will anchor themselves to experience out storms, however the storms push the ships and so they drag their anchors.

A lot of the different cuts are from the Earth itself, like earthquakes and mudslides. Tonga, whose single subsea cable connection was severed by a volcanic eruption, is one other instance.

Human-caused local weather change, which is creating extra excessive storms, worries Microsoft’s Ray. “What retains me awake at evening is large-scale local weather occasions,” he mentioned. In 2012, Hurricane Sandy lower 11 of the 12 high-capacity cables that related the US and Europe, he mentioned.

Most cuts happen nearer to land, the place boat visitors is increased and water is shallower. There, cables are clad in metallic armor and buried within the sea flooring, besides, cable cuts are a matter of when, not if. At any given second, greater than 10 cables are sometimes lower world wide, Google’s Quigley mentioned. The worst season for outages is October to December due to a mixture of harsher climate and fishing exercise.

Cable operators can pinpoint cable lower areas, however restore ships typically should await authorities permits. Repairs common two weeks, Ray mentioned, however three or 4 is widespread, in accordance with.marine cable division chief Takahiro Sumimoto of Japanese telecommunications energy NTT. After the Fukushima earthquake of 2011, it took two months.

“It was too deep, and the cable was lower into items,” Sumimoto mentioned.

A holding grapnel made of a chain of red metal plates, each with dual prongs to grab a subsea cable from the seafloor

Subsea cables are high-tech creations, however fixing them employs units like grapnels invented lots of of years in the past. This holding grapnel is used to retrieve the ends of lower cables resting on the ocean flooring.


The restore requires a ship to fish up one finish of the damaged cable, typically latching on with the identical sort of grappling tools that is been used for hundreds of years. The ship floats that finish of the cable with a buoy whereas the opposite finish is retrieved. The ship splices the optical fibers again collectively, with splices housed in a thicker package deal.

Making subsea cables sooner

With cables so costly to put in, there is a robust incentive to pack in additional information. There’s loads of room for extra optical fibers, however that strategy is restricted by the necessity for electrical energy for the repeaters.

Immediately’s new cables use 16 pairs of fibers, however a brand new cable that NTT is constructing between the US and Japan employs 20 fiber pairs to succeed in 350Gbps. One other Japanese tech large, NEC, is utilizing 24 fiber pairs to succeed in speeds on its transatlantic cable to 500Tbps, or a half petabit per second.

“Particularly after the pandemic, we noticed a capability scarcity in all places. We urgently must assemble new cables,” Sumimoto mentioned. “The state of affairs is a bit loopy. If we assemble a cable, the capability is straight away offered out.”

Together with the brand new cable installations, typically older cables could be upgraded with new community {hardware}. A latest Ciena improve quadrupled the capability of fiber optic traces with out altering something underwater, Lavallée mentioned.

Microsoft is also betting on a basic enchancment to optical fibers themselves. In December, it acquired an organization referred to as Lumenisity growing hole fibers with a tiny central tube of air. The velocity of sunshine in air is 47% sooner than in glass, a discount to the communication delay often called latency that is a key restrict to community efficiency.

Transpacific cables have a latency of about 80 milliseconds. Chopping latency is necessary for time-sensitive laptop interactions like monetary transactions. Microsoft is also fascinated with hole fibers for shorter-haul fiber optic traces, since decrease latency successfully brings information facilities nearer collectively for sooner fallback if one fails.

Additionally coming are fibers with a number of information transmission cores inside as a substitute of only one. “We won’t get far more enchancment in bandwidth over a single fiber,” TeleGeography’s Mauldin mentioned.

A portion of Google’s TPU cable will use two-core fibers, the corporate confirmed, however that is solely a primary step. Fiber optic firm OFS introduced four-core fiber optics this 12 months and sees a path to subsea cable capability of 5Pbps. That is 20 occasions extra information than at the moment’s new cables.

Geopolitical issues of subsea cables

There’s just one web, however strains can present when it connects nations which can be at odds, for instance when the Chinese language authorities blocks Google and Fb or US firms sever their connections to Russia’s web. These techno-political tensions have unfold to the world of subsea cables.

The US successfully blocked three cables that will have instantly linked China and the US, inflicting them to reroute to different Asian nations. And the US has labored to sideline HMN Tech, a Chinese language subsea cable set up and upkeep firm that grew out of Huawei, in accordance with a report by The Monetary Instances.

Learn extra: Survey Exhibits Prospects Dissatisfied With ISPs, however Some Are Higher Than Others

However with many different nations in Southeast Asia, there are numerous oblique connections, with extra to come back. “There are 17 new intra-Asian cables which can be at the moment within the works, and plenty of extra that have not been introduced but,” TeleGeography analyst Tim Stronge mentioned in a June weblog publish. And with regards to web routing guidelines that govern the move of visitors world wide, there are successfully open borders. In different phrases, the web itself would not care a lot about the place precisely the cables go.

The brand new geopolitics has difficult enterprise for SubCom, which serves the US army in addition to non-public firms like Google.

“Lots of governments exert their energy in methods that they had previously,” Coughlan mentioned, and it is not simply the China-US situation. A number of nations, together with Canada and Indonesia, are implementing cabotage legal guidelines that require work achieved of their territorial waters to be achieved by a sovereign ship of that nation.

A black subsea cable coiled several meters deep in a broad cylindrical "tank" inside a cable-laying ship. A person walking on top of the coil is dwarfed by it.

Cable-laying ships maintain lots of of miles of cable spooled up inside three “tanks.” Be aware the size displaying this tank to be 7 meters (22 ft) deep. This exhibits a section of the Merea cable constructed by Microsoft and Fb mother or father Meta.


“That is resulting in a variety of issues across the period of permits and how you can carry out the work,” Coughlan mentioned. “Due to these cabotage legal guidelines, cables are more durable to place in. They take longer. A few of these nations solely have one ship, and you need to wait to get it.”

However finally the financial incentives to construct the cable normally prevail.

“No matter huge dustups there are going to be — commerce wars, precise wars — when it will get to the native stage, the native nations need these cables,” SubCom’s Coughlan mentioned. “That is the one purpose this will get constructed.”

Subsea cable vulnerabilities

Cable vulnerabilities are actual. Anchors and fishing tools are the primary dangers, notably in crowded corridors the place there are a number of cables. The cables are designed to thwart corrosive salt water, not an attacking human.

“It could not take a lot to interrupt these cables. And a foul actor might do it,” Coughlan mentioned. A 2017 suppose tank paper by Rishi Sunak, who’s since turn into prime minister of the UK, concluded that subsea cables are “indispensible, insecure.”

In a 2021 report, the Heart for a New American Safety, a bipartisan nationwide safety suppose tank, concluded that subsea cables are weak. It simulated Chinese language and Russian army actions utilizing adversarial “purple groups.” In these simulations, Chinese language assaults lower off Taiwan, Japan, Guam and Hawaii, however Russian attackers had a more durable time because of the massive variety of Atlantic subsea cables.

“In CNAS wargames, Chinese language and Russian purple groups launched aggressive assaults on undersea cables, particularly the place they ‘land’ ashore. In practically each case, these assaults allowed purple groups to disrupt and degrade US, allied, and associate communications, and contributed to confusion and distraction on the strategic stage as governments have been pressured to answer sudden losses of connectivity,” CNAS senior fellow Chris Dougherty mentioned within the report.

A subsea cable, covered in black protective tar, stretches across a sandy beach out into the ocean

The Marea cable from Microsoft and Meta is high-tech sufficient to hold 200 terabits of information per second, however employs centuries-old nautical know-how too: It is coated in tar.


Sunak really useful a treaty to guard cables, NATO wargames to higher perceive their significance, and sensors on the cable to higher detect threats. Probably the most sensible recommendation, although, was easy: construct extra cables for geographic variety and redundancy.

Constructing a extra resilient subsea cable community

Given the significance and vulnerability of subsea cables, it is no shock there is a race afoot to make the know-how extra strong.

That is why there is a main push to develop to new touchdown websites. When Hurricane Sandy struck, all essentially the most highly effective transatlantic cables landed in New York and New Jersey. Now extra go away from Massachusetts, Virginia, South Carolina and Florida.

“When you run all cables on the identical path, you are an anchor drag away from a number of cables being introduced down,” Quigley mentioned.

Usually, operators will swap capability on every others’ cables, entry that offers every a fallback information pathway if their cable is lower. Successfully, they don’t seem to be placing all their communication eggs in a single cable basket.

In the end, the geographic variety Sunak seeks is turning into a actuality, boosted by higher branching know-how that makes multistop cables economical. The brand new Sea-Me-We 6 cable stretches from France to Singapore by the use of 17 different nations. And new cables are being constructed to attach Europe, Africa, the Center East, Asia, the Americas and plenty of island nations.

“They’re all around the world,” Ciena’s Levallée mentioned. “There may be actually a mesh of those cables.”

CNET magazine cover mockup with subsea cable illustration and text reading "The secret life of the 500+ cables that run the internet."

Zooey Liao/CNET

Visible Designer | Zooey Liao

Senior Undertaking Supervisor | Danielle Ramirez

Inventive Director | Brandon Douglas

Director of Content material | Jonathan Skillings

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