[LINK] The Secret Life of the 500+ Cables That Run the Internet (Part 1)

[Stephen Loosley]

The Secret Life of the 500+ Cables That Run the Internet

Laced across the cold depths of the world's oceans is a network of multimillion-dollar cables, which have become the vital connections of our online lives.

By Stephen Shankland Aug. 6, 2023 https://www.cnet.com/home/internet/features/the-secret-life-of-the-500-cables-that-run-the-internet/


The concert is in London. You're watching it live from your home in Atlanta. What makes that possible is a network of subsea cables draped across the cold, dark contours of the ocean floor, transmitting sights and sounds at the speed of light through strands of glass fiber as thin as your hair but thousands of miles long.

These cables, only about as thick as a garden hose, are high-tech marvels. The fastest, the newly completed transatlantic cable called Amitié and funded by Microsoft, Meta and others, can carry 400 terabits of data per second. That's 400,000 times faster than your home broadband if you're lucky enough to have high-end gigabit service.

And yet subsea cables are low-tech, too, coated in tar and unspooled by ships employing basically the same process used in the 1850s to lay the first transatlantic telegraph cable. SubCom, a subsea-cable maker based in New Jersey, evolved from a rope manufacturer with a factory next to a deep-water port for easy loading onto ships.

Though satellite links are becoming more important with orbiting systems like SpaceX's Starlink, subsea cables are the workhorses of global commerce and communications, carrying more than 99% of traffic between continents.

TeleGeography, an analyst firm that tracks the business, knows of 552 existing and planned subsea cables, and more are on the way as the internet spreads to every part of the globe and every corner of our lives.

You probably know that tech giants like Meta, Microsoft, Amazon and Google run the brains of the internet. They're called "hyperscalers" for operating hundreds of data centers packed with millions of servers. You might not know that they also increasingly run the internet's nervous system, too.

"The whole network of undersea cables is the lifeblood of the economy," said Alan Mauldin, an analyst with TeleGeography. "It's how we're sending emails and phone calls and YouTube videos and financial transactions."

Two thirds of traffic comes from the hyperscalers, according to Telegeography. And the data demands of hyperscalers' subsea cable is surging 45% to 60% per year, said SubCom Chief Executive David Coughlan. "Their underlying growth is fairly spectacular," he said.

Hyperscalers' data demands are driven not just by their own content needs, like Instagram photos and YouTube videos viewed around the world. These companies also often operate the cloud computing businesses, like Amazon Web Services and Microsoft Azure, that underlie millions of businesses' global operations.

"As the world's hunger for content continues to increase, you need to have the infrastructure in place to be able to serve that," said Brian Quigley, who oversees Google's subsea and terrestrial networks.

In this article:

Why subsea cables are reaching everywhere
The origin story of subsea communications
The tech inside subsea cables
How ships install subsea cables
Fixing severed subsea cables
Faster new subsea cable tech
Geopolitical tensions with subsea cables
Vulnerabilities in subsea cables
Making the subsea network more resilient

The first subsea cables spanned major communication routes like London to New York. Those remain critical, but newer routes are bringing bandwidth far off the beaten track: 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 town of Sitka, Alaska.

It's all part of a gradual transformation of subsea communications. Where once cables were the exception, linking a few high-priority urban centers, now they're becoming a world-spanning mesh. In other words, despite high costs and exotic technology, subsea cables are coming to resemble the rest of the internet.

"The whole network of undersea cables is the lifeblood of the economy. It's how we're sending emails and phone calls and YouTube videos and financial transactions."  Alan Mauldin, TeleGeography analyst

But as more internet traffic traverses subsea cables, there's also reason to worry about them. The explosive sabotage last year of the Nordstream 1 and 2 natural gas pipelines connecting Russia and Europe was much more logistically difficult than cutting an internet cable the thickness of your thumb. An ally of Russian leader Vladimir Putin said subsea cables are fair game for attack. Taiwan has 27 subsea cable connections that the Chinese military could see as tempting targets in an attack.

"There's a lot of talk these days about how space is the next contested domain. But I think undersea is going to be very much a contested domain," said Steve Bowsher, president of In-Q-Tel, a CIA-backed nonprofit that invests in startups on behalf of the CIA, FBI, NSA and other US government agencies. "Those are going to be targets in any sort of kinetic conflict."

The risks are vivid: Vietnam's internet performance suffered thanks to outages on all five of its cables for months earlier this year, and the volcanic explosion on the island of Tonga severed it from most communications for weeks.

But those risks are dwarfed by the very real benefits, from the macroeconomic to the purely personal. The network is growing more reliable and capable with faster speeds and a surge in new cables extending the network beyond today's 870,000 miles of routes, and that'll coax more and more countries to join.

That makes the internet richer and more resilient for all of us — including you getting work done and finding entertainment after the workday's over.

Why subsea cables are reaching everywhere

The economic advantages are considerable. Subsea cable links mean faster internet speeds, lower prices, a 3% to 4% boost in employment and a 5% to 7% boost to economic activity, McKinsey estimates.

At the same time that hyperscalers' traffic demands were surging, the telecommunications companies that traditionally installed subsea cables pulled back from the market.

"Roughly 10 years ago, a lot of the traditional telco providers started to really focus on wireless and what was happening within their last-mile networks," said Frank Rey, who leads hyperscale network connectivity for Microsoft's Azure cloud computing business. The wait for new cables grew longer, with the planning phase alone stretching to three to five years. The hyperscalers needed to take control.

Hyperscalers initially began with investments in others' projects, a natural move given that subsea cables are often operated by consortia of many allies. Increasingly, hyperscalers now build their own.

The result: a massive cable buildout. TeleGeography, which tracks subsea cables closely, projects $10 billion will be spent on new subsea cables from 2023 to 2025 around the world. Google-owned cables already built include Curie, Dunant, Equiano, Firmina and Grace Hopper, and two transpacific cables are coming, too: Topaz this year and, with AT&T and other partners, TPU in 2025.

Such cables don't come cheap: A transatlantic cable costs about $250 million to $300 million to install, Mauldin said.

The cables are critical. If one Azure region fails, data centers in another region come online to ensure customers' data and services keep humming. In the US and Europe, terrestrial cables shoulder most of the load, but in Southeast Asia, subsea cables dominate, Rey said.

With the hyperscalers in charge, pushing data instead of voice calls, subsea networks had to become much more reliable. It might be a minor irritation to get a busy signal or dropped call, but interruptions to computer services are much more disruptive. "If that drops, you lose your mind," Coughlan said. "The networks we make today are dramatically better than what we made 10 years ago."

The number of subsea internet cables has surged. By 2025, a total of 552 should be operational.
Data: TeleGeography; graphic: Viva Tung/CNET

The origin story of subsea communications

Today's cables send up to 250 terabits per second of data, but their technology dates back to the 1800s when scientists and engineers like Werner Siemens figured out how to lay telegraph cables under rivers, the English Channel and the Mediterranean Sea. Many of the early cables failed, in part because the weight of a cable being laid on the bottom of the ocean would rip the cable in two. The first transatlantic cable project that succeeded operated for only three months in 1858 before failing and could only send just over one word per minute.

But investors eager to cash in on rapid communications underwrote the development of better technology. Higher copper purity improved signal transmission, stronger sheathing reduced cable breaks, repeaters installed periodically along the cable boosted signal strength and polyethylene insulation replaced the earlier rubberlike material harvested from gutta-percha trees.

Telephone calls eventually replaced telegraph messages, pushing technology further. A transatlantic cable installed in 1973 could handle 1,800 simultaneous conversations. In 1988, AT&T installed the first transatlantic cable to use glass fiber optic strands instead of copper wires, an innovation that boosted capacity to 40,000 simultaneous phone 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.

SubCom's subsea cable factory dates back to its rope-making roots in the 1800s. "Most rope in that time was used on ships or needed to be transported by ships," CEO Coughlan said. "A factory on a deep port, with quick access to the ocean and with winding capabilities, is what was needed to transform into the telephone cable business."

The tech inside subsea cables

Fiber optic lines transmit data as pulses of laser light. As with terrestrial fiber optic lines, using multiple frequencies of light — colors, to you and me — means more data can be sent at once. Network equipment ashore at either end of a cable encodes data into the light for transmission and decodes it after it's received.

Fiber optics are great for fast broadband and long-haul data transmission, but the technology has its limits. That's why there's a big bulge in the cable every 30 to 60 miles called a repeater, to boost the signal strength.

Repeaters require power, though, and that's where another part of the cable construction comes into play. Outside the fiber optic strands, a copper layer carries electricity at up to 18,000 volts. That's enough to power repeaters all the way across the Pacific Ocean just from one end of the cable, though power typically is available from both ends for greater reliability.

Why not keep raising the laser power, so you don't need repeaters as often? Because boosting it too high would eventually melt the fibers, said Brian Lavallée, a senior director at networking technology giant Ciena.

His company makes the network equipment at either end of the subsea cables, employing different data encoding methods — manipulating light waves' frequency, phase and amplitude — to squeeze as much data as possible onto each fiber.

"We've been able to get very, very close to the Shannon limit, which is the maximum amount of information you can send down a communication medium," Lavallée said.


How ships install subsea cables  (Continued Part 2)