Under the Sea: In the Age of Wireless, Can't We Do Better than Intercontinental Fiber Optic Cables?

This week's outage in Africa reminds us of the vulnerable physicality of the Internet

Fiber Optic Cables

rpongsaj (CC licensed)

On Saturday, a ship waiting to enter the Kenyan port city of Mombasa wandered into a restricted area and dropped its anchor, inadvertently severing a major undersea Internet and phone link to East Africa. This kind of thing happens from time to time, but Saturday's incident represents a particular stroke of bad timing. The cable severed was already overworked, rerouting data from three other cables that were accidentally severed a week prior in the Red Sea. All said, these fiber-optic channels are the backbone of East Africa's telecommunications infrastructure. Now one single undersea fiber-optic link is left to carry the entire load for all of East Africa, slowing internet connections in Rwanda, Kenya, Burundi, Ethiopia, Tanzania, and South Sudan by 20 percent until repairs are made, a process that could take weeks.

Before plugging into the high-capacity subsea fiber optic network three years ago, most Internet traffic in East Africa moved through expensive satellite connections or painfully slow telephone lines. Since then economies in the region have come to rely on their increased connectivity, so this weekend's incident comes dangerously close to spelling a small economic disaster. It also raises a larger question: Why, when global economies and day-to-day life are so reliant on access to the Internet, are we still relying on these seemingly vulnerable undersea cables, these accident-prone physical "tubes" connecting continents across the oceans? Why, in a world that's increasingly wireless, are we still so wired? Isn't there a better way to connect the globe?

The answer is: Not really. Fiber optic communication, for all of its shortcomings, is actually pretty amazing, and it's getting better by the year. Accidents do happen. In 2006 earthquakes in the Luzon Strait near Taiwan severed seven of nine cables and wrought havoc on communications networks for weeks, and twice in 2008 cables in the Mediterranean were damaged, disrupting communications in the Middle East, Africa, and the Indian subcontinent (and that's just two recent examples--there are many, many more). But there's really no technology that can touch our current fiber optics technology. The solution to problems like those East Africa is currently experiencing is not less fiber optic cable, but more.

"It's amazing that we're reliant on these physical links, but the reason we are is because of the kind of quantum leaps that fiber optic technology offers," says Andrew Blum, author of the forthcoming book Tubes: A Journey to the Center of the Internet. The physical cables running along (and sometimes under) the seabed carry huge volumes of data in the form of light, orders of magnitude more data than can be packed into radio signals that might be beamed wirelessly via satellites or antenna towers. The idea of replacing those cables with some kind of through-the-air technology is tempting, but for the foreseeable future we're stuck with fiber optics.

Fiber optic cables carry orders of magnitude more data than can be beamed wirelessly "The problem is that the volumes of data we're talking about require a very wide spectrum of frequencies," Marvin Sirbu, professor of engineering and public policy at Carnegie Mellon University, says. "And in order to get a wide spectrum of frequencies you need to get into very high-frequency electromagnetic waves. Light waves are very, very high-frequency. If you look at the frequencies we normally think of as radio waves, to find that much spectrum you'd have to be at frequencies so high that--like light--they fade in fog or in rain, and therefore can't really be used to go to a satellite and back, or even over long distances on the ground."

Instead, Sirbu says, we put those high-frequency signals into optical fiber in the form of light. The fiber is extremely transparent so the signal doesn't fade over distance. There's no fog or rain or other atmospheric moisture inside to interfere with the signal, so it maintains its integrity whether traveling across the room or across the Pacific. When you run out of capacity, you lay a new cable. Or, even better, you can dial up the capacity in the cables already laid.

This is where fiber optics creates those "quantum leaps" forward, says Blum. The standard operating unit for fiber optics right now is something like 10-gigabits per second. But new optical modules that are being swapped into common systems boost that capacity to 40 or even 100 gigabits per second. The same cables can then carry ten times more capacity, growing the system without laying a single new cable on the seafloor. Other tricks--involving everything from new ways of channeling signals to implementing lenses known as "time telescopes" to manipulate light pulses--could potentially keep that capacity growing at a rapid pace for the foreseeable future.

The key to averting disasters like the one East Africa is flirting with is redundancy, Sirbu says. "If you look at the U.S., we have cable landing sites at many different places, from Florida to Maine and all up and down the West Coast as well," Sirbu says. "Given the interconnection of networks around the world, if fiber going into one landing location is broken there is fiber landing at other locations that will still be operational. But Africa is probably the continent least densely served by fiber optics, especially when compared to Europe, North America, or East Asia. They're in a riskier position."

That's a problem for East Africa, particularly in a situation like this wherein two separate incidents have severed two of the three main fiber optic nerves feeding data into and out of the region. And while it seems that vulnerable undersea cables are the cause of the region's current connectivity woes, the key to ensuring that East Africa doesn't find its communications infrastructure hanging by a single fiber optic thread ever again--to ensure it doesn't end up temporarily back in the days of dial-up and satellite signals--is route diversity. In other words, the answer is more fiber optics cables, not fewer.

"These cuts are always exciting because these are the moments that remind everyone that the cables are there," Blum says. "This cut in particular is more exciting because it's the first time you really get to see what it means for East Africa to have fiber when three years ago it didn't. So I optimistically look at it upside down. Its only the incredible capacity of fiber optic technology that has allowed the Internet to progress across the world. You wouldn't have this global Internet without fiber optics--that's what's so amazing about it."