Continued: https://www.cnet.com/home/internet/features/the-secret-life-of-the-500-cables-that-run-the-internet/
How ships install subsea cables Companies installing a cable start by picking a route, surveying the route to dodge marine problems like nature preserves, rough seafloor and other cables. When multiple countries, telecommunications firms and businesses are involved, finding an agreeable route and obtaining permits can be very complex. The cables themselves are gradually paid out from specialized ships. That isn't as simple as unspooling your string when you're flying a kite on a windy day. Fiber optic strands are narrow, but subsea cables are thicker, heavier and bulkier. They're stored in metal 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 hold 5,000 tons of cable, which works out to about 1,800 miles of lightweight cable and 600 miles of cable that's been armored for busy waters. SubCom has to figure out the installation order for each cable segment and make sure that when installation begins, the right end of the cable is at the top of the coil. That means before loading onto the ship, while the cable is stored at SubCom's depot, it must be stored "flipped" the other way up. It reverses direction to the correct configuration as it's transferred loop by loop onto the ship, SubCom's Coughlan said. That's already complicated, but weather, permits or other concerns can force changes to the installation order. That can require flipping a cable at sea with two ships side by side. In a very digital business it turns out to be a very analog problem trying to account for factors like the ships lurching on the open ocean and the cable's weight and bending limits. "We have one guy in particular that's just a savant at this," Coughlan said. "He has to be able to solve it with his hand with string first, because we found the computer modeling never works." Near shore, cables are armored with steel cable and buried in the sea floor with a special plow towed behind the ship. The plow pulls up into the water any time the new cable crosses another that's already installed. In the deeper ocean, where fishing equipment and anchors aren't a problem, the cable has less protection and is simply laid on the bottom of the sea floor. Fixing severed subsea cables Subsea cables are pretty tough, but every three days or so, one gets cut, TeleGeography said. The primary culprits, accounting for about 85% of cuts, are fishing equipment and anchors. Ships often will anchor themselves to ride out storms, but the storms push the ships and they drag their anchors. Most of the other cuts are from the Earth itself, like earthquakes and mudslides. Tonga, whose single subsea cable connection was severed by a volcanic eruption, is another example. Human-caused climate change, which is creating more extreme storms, worries Microsoft's Rey. "What keeps me awake at night is large-scale climate events," he said. In 2012, Hurricane Sandy cut 11 of the 12 high-capacity cables that connected the US and Europe, he said. Most cuts occur closer to land, where boat traffic is higher and water is shallower. There, cables are clad in metal armor and buried in the sea floor, but even so, cable cuts are a matter of when, not if. At any given moment, more than 10 cables are typically cut around the world, Google's Quigley said. The worst season for outages is October to December because of a combination of harsher weather and fishing activity. Cable operators can pinpoint cable cut locations, but repair ships often must await government permits. Repairs average two weeks, Rey said, but three or four is common, according to.marine cable division chief Takahiro Sumimoto of Japanese telecommunications power NTT. After the Fukushima earthquake of 2011, it took two months. "It was too deep, and the cable was cut into pieces," Sumimoto said. 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, but fixing them employs devices like grapnels invented hundreds of years ago. This holding grapnel is used to retrieve the ends of cut cables resting on the ocean floor. The repair requires a ship to fish up one end of the broken cable, often latching on with the same kind of grappling equipment that's been used for centuries. The ship floats that end of the cable with a buoy while the other end is retrieved. The ship splices the optical fibers back together, with splices housed in a thicker package. Faster new subsea cable tech With cables so expensive to install, there's a strong incentive to pack in more data. There's plenty of room for more optical fibers, but that approach is limited by the need for electrical power for the repeaters. Today's new cables use 16 pairs of fibers, but a new cable that NTT is building between the US and Japan employs 20 fiber pairs to reach 350Gbps. Another Japanese tech giant, NEC, is using 24 fiber pairs to reach speeds on its transatlantic cable to 500Tbps, or a half petabit per second. "Especially after the pandemic, we observed a capacity shortage everywhere. We urgently need to construct new cables," Sumimoto said. "The situation is a bit crazy. If we construct a cable, the capacity is immediately sold out." Along with the new cable installations, sometimes older cables can be upgraded with new network hardware. A recent Ciena upgrade quadrupled the capacity of fiber optic lines without changing anything underwater, Lavallée said. "The networks we make today are dramatically better than what we made 10 years ago." David Coughlan, CEO, SubCom Microsoft also is betting on a fundamental improvement to optical fibers themselves. In December, it acquired a company called Lumenisity developing hollow fibers with a tiny central tube of air. The speed of light in air is 47% faster than in glass, a reduction to the communication delay known as latency that's a key limit to network performance. Transpacific cables have a latency of about 80 milliseconds. Cutting latency is important for time-sensitive computer interactions like financial transactions. Microsoft also is interested in hollow fibers for shorter-haul fiber optic lines, since lower latency effectively brings data centers closer together for faster fallback if one fails. Also coming are fibers with multiple data transmission cores inside instead of just one. "We can't get much more improvement in bandwidth over a single fiber," TeleGeography's Mauldin said. A portion of Google's TPU cable will use two-core fibers, the company confirmed, but that's only a first step. Fiber optic company OFS announced four-core fiber optics this year and sees a path to subsea cable capacity of 5Pbps. That's 20 times more data than today's new cables. Geopolitical tensions with subsea cables There's only one internet, but strains can show when it connects countries that are at odds, for example when the Chinese government blocks Google and Facebook or US companies sever their connections to Russia's internet. These techno-political tensions have spread to the world of subsea cables. The US effectively blocked three cables that would have directly linked China and the US, causing them to reroute to other Asian nations. And the US has worked to sideline HMN Tech, a Chinese subsea cable installation and maintenance company that grew out of Huawei, according to a report by The Financial Times. But with many other countries in Southeast Asia, there are many indirect connections, with more to come. "There are 17 new intra-Asian cables that are currently in the works, and many more that haven't been announced yet," TeleGeography analyst Tim Stronge said in a June blog post. And when it comes to internet routing rules that govern the flow of traffic around the world, there are effectively open borders. In other words, the internet itself doesn't care much about where exactly the cables go. The new geopolitics has complicated business for SubCom, which serves the US military as well as private companies like Google. "A lot of governments exert their power in ways they had in the past," Coughlan said, and it isn't just the China-US issue. Several countries, including Canada and Indonesia, are enforcing cabotage laws that require work done in their territorial waters to be done by a sovereign ship of that nation. "This is leading to a lot of complications around the duration of permits and how to perform the work," Coughlan said. "Because of these cabotage laws, cables are harder to put in. They take longer. Some of these countries only have one ship, and you have to wait to get it." But ultimately the economic incentives to build the cable usually prevail. "Whatever big dustups there are going to be — trade wars, actual wars — when it gets to the local level, the local countries want these cables," SubCom's Coughlan said. "That's the only reason this gets built." Vulnerabilities in subsea cables Cable vulnerabilities are real. Anchors and fishing equipment are the main risks, particularly in crowded corridors where there are multiple cables. The cables are designed to thwart corrosive salt water, not an attacking human. "It would not take much to break these cables. And a bad actor could do it," Coughlan said. A 2017 think tank paper by Rishi Sunak, who's since become prime minister of the UK, concluded that subsea cables are "indispensible, insecure." In a 2021 report, the Center for a New American Security, a bipartisan national security think tank, concluded that subsea cables are vulnerable. It simulated Chinese and Russian military actions using adversarial "red teams." In these simulations, Chinese attacks cut off Taiwan, Japan, Guam and Hawaii, but Russian attackers had a harder time thanks to the large number of Atlantic subsea cables. "In CNAS wargames, Chinese and Russian red teams launched aggressive attacks on undersea cables, specifically where they 'land' ashore. In nearly every case, these attacks allowed red teams to disrupt and degrade US, allied, and partner communications, and contributed to confusion and distraction at the strategic level as governments were forced to respond to sudden losses of connectivity," CNAS senior fellow Chris Dougherty said in the report. Sunak recommended a treaty to protect cables, NATO wargames to better understand their importance, and sensors on the cable to better detect threats. The most practical advice, though, was simple: build more cables for geographic diversity and redundancy. Making the subsea network more resilient Given the importance and vulnerability of subsea cables, it's no surprise there's a race afoot to make the technology more robust. That's why there's a major push to expand to new landing sites. When Hurricane Sandy struck, all the most powerful transatlantic cables landed in New York and New Jersey. Now more leave from Massachusetts, Virginia, South Carolina and Florida. "If you run all cables on the same path, you're an anchor drag away from multiple cables being brought down," Quigley said. Often, operators will swap capacity on each others' cables, access that gives each a fallback data pathway if their cable is cut. Effectively, they're not putting all their communication eggs in one cable basket. "People are trying to build resiliency into the system," In-Q-Tel's Bowsher said. Ultimately, the geographic diversity Sunak seeks is becoming a reality, boosted by better branching technology that makes multistop cables economical. The new Sea-Me-We 6 cable stretches from France to Singapore by way of 17 other countries. And new cables are being built to connect Europe, Africa, the Middle East, Asia, the Americas and many island nations. "They're all over the world," Ciena's Levallée said. "There is truly a mesh of these cables." -- _______________________________________________ Link mailing list [email protected] https://mailman.anu.edu.au/mailman/listinfo/link
