Mar 25, 2013

Underwater Cables Are A Thing


As we made our way around the country, Amanda and I would ask people how they believe their internet physically works. If you were to explain how the water in your house gets to the tap, for instance, you could point out a few key elements like the well, the pipes in your wall, the water heater, etc. But could you do that for the internet? Not surprisingly, many people were unsure about what the little cable box with the blinky light does let alone what the basic elements of our communication infrastructure look like. One of the most common guesses is that somewhere in the process the signal goes into space and bounces off a satellite. I think this reasoning is just a matter of quick deduction-- bouncing radio signals off a tower or dish in the sky must be quicker and more efficient than running wires all over the place, right? Well, I was excited to find out that it actually isn't, and we really have laid wires across oceans and over mountains all over the planet. 

Lets take it all the way back to the telegraph-- the first electrical communication system. I find it's somewhat common to imagine the wires even in this early system would at some point run into a radio station in order to be beamed across the ocean. After all, the 1800's seems like a relatively early period in time for something advanced like undersea cables to be possible. Radio, however, was the advanced technology that wasn't yet possible. The first wireless transmission systems weren't developed until the early 1900's, while the telegraph had been around since the 1830's. For about sixty years during the 1800's telegraph was the quickest way to transmit information, so with that in mind it is less surprising an undersea cable was considered important to figure out.

The telephone poles running up and down our streets clearly illustrate how possible it is to run a wire from home to home all the way across a continent. Getting across the ocean, however, requires a little bit more from our imagination. Just picturing an uninterrupted length of cable spanning the Atlantic gets me thinking about sunken treasure ships, undersea canyons, and whales. An ocean is a big dark unknown area, so the idea that groups of people would take a stab at conquering it with a cable back in the 1850's seems ridiculous, but that's exactly what they did. Bit by bit cable technology was improved and cables were successfully laid across multiple oceans. The image above looks like a trade routes for ships, but it's an early map of the new kind of trade route we've developed over wires.

There's a lot of information about underwater, or submarine, cables online-- it's a vastly ambitious ongoing engineering feat that's been underway for well over a hundred years now, so there ought to be. You'll readily find answers to any question you have about the subject on Google, but I've compiled below a couple of quotes found from a variety of sources that will give you a quick overview of the topic.

...In 1870, a new cable was laid between England and France, and Napoleon III used it to send a congratulatory message to Queen Victoria. Hours later, a French fisherman hauled the cable up into his boat, identified it as either the tail of a sea monster or a new species of gold-bearing seaweed, and cut off a chunk to take home. Thus was inaugurated an almost incredibly hostile relationship between the cable industry and fishermen. Almost anyone in the cable business will be glad, even eager, to tell you that since 1870 the intelligence and civic responsibility of fisherman have only degraded. Fishermen, for their part, tend to see everyone in the cable business as hard-hearted bluebloods out to screw the common man...

...Clearly, submarine cable repair is a good business to be in. Cable repair ships are standing by in ports all over the world, on 24-hour call, waiting for a break to happen somewhere in their neighborhood. They are called agreement ships... 

...By the year 1870, Kelvin and others had finally worked the bugs out of the technology. A three-master anchored off this beach in that year and landed a cable that eventually ran to Lisbon, Gibraltar, Malta, Alexandria, Cairo, Suez, Aden (now part of Yemen), Bombay, over land to the east coast of India, then on to Penang, Malacca, Singapore, Batavia (later Jakarta), and finally to Darwin, Australia. It was Australia's first direct link to Great Britain and, hardly by coincidence, also connected every British outpost of importance in between. It was the spinal cord of the Empire...

...The basic problem of slack is akin to a famous question underlying the mathematical field of fractals: How long is the coastline of Great Britain? If I take a wall map of the isle and measure it with a ruler and multiply by the map's scale, I'll get one figure. If I do the same thing using a set of large-scale ordnance survey maps, I'll get a much higher figure because those maps will show zigs and zags in the coastline that are polished to straight lines on the wall map. But if I went all the way around the coast with a tape measure, I'd pick up even smaller variations and get an even larger number. If I did it with calipers, the number would be larger still. This process can be repeated more or less indefinitely, and so it is impossible to answer the original question straightforwardly. The length of the coastline of Great Britain must be defined in terms of fractal geometry...


Cable placed at the bottom of the ocean is actually laid in a trench with a plow!





...Britain's very first action after declaring war on Germany in World War I was to have the cable ship Teleconia cut the five cables linking Germany with North America. Thereafter the only way Germany could communicate was by wireless, and that meant that Room 40 could listen in...

...In the 1980s, fiber optic cables were developed. The first transatlantic telephone cable to use optical fiber was TAT-8, which went into operation in 1988. A fiber-optic cable comprises multiple pairs of fibers. Each pair has one fiber in each direction. TAT-8 had two operational pairs and one backup pair...


...As of 2006, overseas satellite links accounted for only 1 percent of international traffic, while the remainder was carried by undersea cable. The reliability of submarine cables is high, especially when (as noted above) multiple paths are available in the event of a cable break. Also, the total carrying capacity of submarine cables is in the terabits per second, while satellites typically offer only megabits per second and display higher latency. However, a typical multi-terabit, transoceanic submarine cable system costs several hundred million dollars to construct.
As a result of these cables' cost and usefulness, they are highly valued not only by the corporations building and operating them for profit, but also by national governments. For instance, the Australian government considers its submarine cable systems to be "vital to the national economy". Accordingly, the Australian Communications and Media Authority (ACMA) has created protection zones that restrict activities that could potentially damage cables linking Australia to the rest of the world. The ACMA also regulates all projects to install new submarine cables...


Here's a short video from the Discovery Channel about undersea cable. Be sure to see the storage room at around the 4:30 mark:



And finally, here are some maps of where all these cables are all around the world:

Whether you have time to explore the history of submarine cables or not, it's worth remembering that the internet is built on an infrastructure first developed in the 1800's. Because computer technology has made the next evolutionary steps in communications bigger and faster it's easy to imagine this is all quite brand new and separate from other forms of communication. When put in perspective, though, the evolution of communication from telegraph, to telephone, fax, email, and now to video conferencing all centered around this impressive web of wires laid around the globe is easier to see.