The Internet is an integral part of all of our lives. It’s something we use every day to conduct the simplest to most complex of tasks. But how many of us actually know how telecommunication signals are transmitted around the world, allowing us to connect with people in different countries?
Put simply, the Internet is powered by submarine communications cables (essentially just underwater cables) installed by ocean vessels called cable-layers. The first transoceanic cable, a copper telegraph wire, was laid across the Atlantic Ocean in 1866. In the 1990s, analogue cables which had been positioned underwater in the 1950s were replaced by fibre optic cables which continue to be used today. These cables are similar in thickness to a regular garden hose and have the ability to carry tens of terabits of the world’s data traffic at 99.7% the speed of light. This data includes; Internet, phone calls and even TV transmissions between continents.
As recorded in 2014, there are 285 cables on the seafloor, of which 22 are currently inactive. Each cable holds a life expectancy of 25 years, after this time period they are considered financially unviable as the volume of data and information they can carry begins to decrease.
Recently, the need and appropriateness of underwater cables has been under question.
Source: A 2015 map of 278 in-service and 21 planned undersea cables.
Underwater Cables Vs. Satellites
With the popularity of satellites on the rise, people have begun to wonder whether undersea cables are slowly becoming a thing of the past. However, these cables hold significant benefits over satellites which prove them to still be the best option for transmitting information.
Fibre optic cables have been recognised as state-of-the-art global communications conductors, incorporating cloud-computing technology to improve the security, data recovery and efficiency of information transfers. Furthermore, as these cables utilise light to code information and remain unaffected by weather changes, they provide a faster and cheaper way of carrying data than satellites.
Satellites have two primary problems, latency and bit loss (loss of data) which increases the time needed to send and receive signals to and from space. In addition, a single satellite radio channel has limited bandwidth compared to the bandwidth available using a single fibre optic cable. This is because light has a higher frequency and shorter wavelength than microwaves (which are used in satellite transmissions).
The benefits of underwater cables over satellites has seen places like Antarctica where research stations produce data in far greater quantities than they could have transmitted using satellites.
Damages to underwater cables
Many researchers agree that issues with underwater cables predominantly stem from human error rather than technological errors.
As they are positioned underwater, the cables are prone to accidental breakage from dropped anchors, fishing (together accounting for 60% of cut cable incidents), submarines and construction projects. In 2005, Pakistan was cut off from the rest of the world when its Internet and mobile phone links were severed by a fault in a main submarine cable off Karachi coast, affecting thousands of people.
While the International Cable Protection Committee is attempting to reduce such unintentional breaks by burying steel armoured cables under the seafloor, it isn’t possible to prevent every ocean vessel from getting critically close to the cables. Creating boundaries and ‘off-limit’ zones in efforts to achieve this would profoundly disrupt the global economy, doing more harm than good.
Source: A diver fixing an under water cable.
Natural disasters can also be a source of disruption to the Internet by damaging undersea cables, which is what happened during the 2011 Japanese earthquake and tsunami.
Sharks also pose a problem as they chew on the underwater cables making them difficult to maintain. To tackle this issue, companies such as Google have begun to protect their cables using shark-proof wire wrappers.
Cable sabotage, while rare now, was a common occurrence during both World Wars. The most recent recorded incident is speculated to have been outside Alexandria, Egypt in 2008, where 70% of the country’s internet was cut which affected millions of people.
Despite these drawbacks, underwater cables are still able to fundamentally protect global information traffic as redundancy is built into the system. Having more cable capacity than the volume of traffic means that if breakage to a cable does occur, information is immediately redirected through other cables.
Future of underwater cables
Since the early 2000s, global data consumption has exploded. By 2018, Internet traffic is expected to dramatically rise, growing from 5 gigabytes per capita to 14 gigabytes per capita. This increase presents an immediate capacity issue, which makes it essential for the cables to be regularly updated. To deal with this problem, new techniques in phase modulation and improvements in submarine line terminal equipment (SLTE) have boosted capacity in some places by as much as 8000%. This means underwater cables will continue working at their full potential, and will be more than ready for the anticipated increase in traffic.
However, some researchers predict that as technology continues to advance, we will eventually use satellites as a means of connection and information transmission.
Here at Onque, we’re all about everything digital. The maintenance, development and improvement of online life is something we are passionate about.
We’re interested to know what you think about the debate surrounding the use of satellites over underwater cables. What do you think is our best option for powering the Internet and transmitting information around the world?
Leave us a comment below!