Shining Light on the Top 10 Myths Surrounding Submarine Networks

Despite the fact that submarine cables transmit a tremendous amount of the world's data -- with bandwidth-hungry internet content providers driving almost half of it in 2015 -- "prevailing wisdom" around both the broader and finer points of undersea networks unfortunately suffers from a number of rather common misconceptions.

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Despite the fact that submarine cables transmit a tremendous amount of the world's data -- with bandwidth-hungry internet content providers driving almost half of it in 2015 -- "prevailing wisdom" around both the broader and finer points of undersea networks unfortunately suffers from a number of rather common misconceptions.

Such misconceptions span quite a range: from myths based on past technologies (e.g., satellites) to those that involve toothy marine life. Below are the Top 10 myths around submarine networks that could use some debunking.

1. Submarine networks are just networks on submarines

This is a common misunderstanding for those unfamiliar with the international telecommunications industry, and it's understandable given the term. Although there are indeed networks on submarines, this isn't what is being referred to when discussing international communications. Submarine networks are optical communications networks that interconnect continental landmasses across ocean floors. Perhaps a better term for the networks that lay at the bottom of the world's oceans is "subsea networks."

2. Submarine cables are a new technology

The first reliable trans-Atlantic submarine cable was installed 150 years ago, back in 1866. It connected Ireland to Newfoundland. Although transmission rates then were incredibly slow by today's standards, use of the telegraph cable was far quicker than sending handwritten messages back and forth across the Atlantic Ocean, where reception speed was essentially the sailing time of the ship carrying the message. While submarine cables unfortunately don't get the recognition they deserve, it's amazing to think that the technology we rely on every day to connect with the rest of the world was the brainchild of entrepreneurial visionaries that lived a century and a half ago.

3. Satellites carry most international communications

Although satellites still serve most of the remote regions of the world, they actually account for a relatively tiny portion of the world's international telecommunications traffic. According to the IEEE's "Reliability of Global Undersea Cable Communications Infrastructure" report issued in 2010, "nearly 100% of the world's inter-continental electronic communications traffic is carried by the undersea cable infrastructure," which clearly debunks this common myth.

4. Sharks are eating the internet!

Given the YouTube videos showing sharks biting submerged cables, many understandably believe that sharks are attacking submarine cables. However, according to the International Cable Protection Committee, an organization dedicated to the safe sharing of the seabed with others, this simply isn't the case. According to their latest analysis from 2007 to 2014, no recorded cable faults were attributable to sharks. The truth is, these toothy fish aren't eating the internet.

5. Weather has nothing to do with submarine network faults

This myth is likely related to the understanding that submarine cables are stitched together to form networks located at the bottom of the ocean. As such, how could atmospheric weather affect these submerged cables? Weather conditions, such as hurricanes, can lead to landslides on coastal regions that have the ability to travel deep into the water where submarine cables are situated. This was the case back in August 2009 when Typhoon Morakot led to landslides that damaged several submarine cables off the Taiwanese coast. The reach of Mother Nature is indeed very long and often very unpredictable.

6. Submarine cables are laid in a straight line between landing points

Laying submarine cables in a straight line makes sense to achieve the lowest propagation delays (also known as latency), since the speed of light takes only tens of milliseconds to travel across a submarine cable that's thousands of kilometers in length. A straight-line deployment would also enable use of the shortest length of submarine cable and smallest number of repeaters (which amplify optical signals traversing the cable). The reality is that the bottom of our oceans actually look quite similar to our continents (albeit underwater). They have mountains, volcanoes, ravines, and other natural structures, as well as protected environments like coral reefs and breeding grounds. So although the intention of cable layers is to use the straightest line between the cable landing points, they must snake cables around such obstacles.

7. Submarine networks will be replaced by wireless networks

Wireless networks are everywhere today in the form of cell networks, WiFi, Bluetooth, microwave radio, and other technologies. So why not use wireless across oceans as well? The reality is that traffic is aggregated from multiple terrestrial networks into a few submarine cables, leading to massive amounts of traffic being carried between continental landmasses. Wireless communications technology, which includes satellite networks, simply cannot scale to the required costs, latency, and capacities that submarine cables offer, now or in the foreseeable future.

8. Submarine cables are physically very large

This myth likely comes from misinterpreted images of submarine power cables and pipelines. The former, which serve offshore wind farms, for example, are large compared to submarine telecom cables. Submerged pipelines that carry oil or gas from nearby offshore platforms are also often misidentified as submarine telecom cables. Modern submarine cables are quite small in diameter. They range from around 20 mm for unarmored cables, which are unburied in deeper waters, to around 50 mm for armored cables, which reside closer to coastlines and are buried because they're far more susceptible to vessel damage such as anchoring or fishing activities. To put this into perspective, 20 mm is roughly the diameter of a common residential garden hose or twice the diameter of a typical mountain climbing rope.

9. Submarine cables are harmful to the environment

Although some marine industries do engage in activities that incur widely publicized adverse effects on marine environments, such as offshore drilling operations, this isn't the case for the submarine network industry. The one-time laying of telecom submarine cables is far less damaging than other ongoing marine activities such as trawling, and doesn't use toxic materials or pollutants that injure marine life.

10. There's no need for new submarine cables

The rapid pace in optical transmission technology development and commercialization have allowed submarine cable operators to continually breathe new life into their existing wet plant assets by upgrading channels from 10 Gbps to 40 Gbps and to, most recently, 100 Gbps. Since there's so much capacity still available to be tapped into on existing submarine cables, why do we need more of them? The driver behind placing new submarine cables isn't strictly related to the need for higher capacity. It's often due to other market drivers such as international politics, the need for more redundant routes to protect our increased dependence on the internet, the desire to be a digital hub to attract more business such as data centers, and new bandwidth business models. It should also be noted that most existing submarine cables have been deployed many years to decades ago with a typical 25-year lifespan, so all existing submarine cables will eventually have to be replaced and upgraded. It's just a matter of time.

Brian Lavallée is director, portfolio solutions, at Ciena.

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