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26th October 2022

How Undersea Cables Connect the World

Written by Team Pentanet

26th October 2022


With WiFi, mobile and Bluetooth it’s easy to think of the internet as something that just lives freely in the air all around us, but that couldn’t be further from the truth, or from where it really lives. While locally, the internet is indeed carried through the air and infrastructure such as NBN fibre, between nations the information moves along titanic undersea cables at internet speeds that are simply unimaginable.  

The history of these cables begins in 1842 when Samuel Morse (the creator of morse code) laid a cable across the New York harbour. He wanted to see if it would allow for morse code to be transmitted from one side of the harbour to the other. With the concept proven, it was only a few years later that cable had been laid from Newfoundland to Ireland, connecting America back to Europe and allowing for messages that would have previously taken weeks or months to travel as quickly as a few minutes. 

Since then, these cables have continued to progress, develop and spread. Moving from transmitting morse code to transmitting internet data, their speeds are like nothing we could ever imagine and only keep on growing. In 2013, the average undersea cable could transfer data at internet speeds of 9 Terabytes (or 9000 Gigabytes) per second. By 2022 cables operate at an average of 35TBps. With 1TB being more than enough storage for most home computers, this means these cables are transmitting the entire data storage capacity of a home computer 35 times over every second. 

Already new cables have begun to rapidly exceed that average. The FASTER cable system operates at speeds of 60TBps, while the Merea cable, owned by Meta and Microsoft, which will connect California and Spain reaches internet speeds as high as 160TBps. More locally, the 10,000km Oman-Australia cable (OAC) connecting West Australia to Oman has just been activated. This cable gives Australia its most direct path to the middle east and Europe, operating at 39TBps. 

However fast these seem however, they are nothing compared to the new Transatlantic cable, which promises speeds of 0.5 petabits, which would come out to 500TBps. 

With all these names flying around, you might be wondering how many of these gigantic cables there are. Well, currently there are more than 450 undersea cables linking the continents of the world. These cables are responsible for 99% of the world’s internet traffic and provide the infrastructure needed for ocean-spanning communication. Were you to stretch out all these cables end to end; they would wrap around Earth’s equator more than 28 times.  

Undersea Cables and Ultimate Internet Speeds

Where are they? 

Most cables connecting Australia to the rest of the world land in either Sydney or Perth, with Perth being the premier location to connect the rest of Australia to South Asia and Africa, while Sydney provides the most direct path to the west coast of the US and East Asia. We have multiple cables that pass through Singapore, Hawaii or Papau New Guinea before continuing to connect us to the rest of the world. 

For most cables that pass from western Europe or North Africa, the cables must pass through Egypt, coming on land (though remaining largely underground) temporarily to pass efficiently from the Red Sea to the Mediterranean Sea. Because of this, Telecom Egypt has a monopoly on the transit corridor linking the Red Sea and the Mediterranean Sea. 

Recently, this has begun to shift, after Google successfully installed the Blue-Raman cable, which goes from Mumbai to Italy passing through Saudi Arabia and Iran. This could potentially see the market expanding, allowing for more operators to control these critical transmission points, lowering prices as the competition enters the playing field. 

How do they survive down there? 

The cables are 3 to 4 feet wide and are deployed at 8000 metres deep, which necessitates the need for them to be ludicrously durable. To survive at such depths, they must account for rocky seabeds, curious animals, volcanoes, and the pressure of the deep ocean. For this reason, 99% of that 4-foot cable is devoted to protecting the fibre cables at their centre, which are thinner than a single human hair. 

Despite the substantial protection built into these cables, they are by no means indestructible. More than 100 faults occur with these cables each year, 38% of which are the result of fishing activities and a further 25% of which stem from anchors being dropped on them by ships.  

One such incident saw several countries across the west coast of Africa, the majority of which are serviced by the ACE cable, lose internet for several days when the cable was damaged.  

A smaller but much more local incident saw Tasmania in a six hour digital blackout when two of the three cables connecting the island to the rest of the world were cut (by astounding coincidence) on the same day, in different places by different construction companies in different incidents. This break saw all but emergency and priority services such as triple zero calls disrupted on the island until both cables were restored. 

Though most regions are serviced by multiple redundant cables, these incidents in more remotely serviced regions goes to show how critical the safety of their infrastructure is. 

This need for safety and security has been on the rise recently, with increasing fears of potential taps into these cables granting nations access to confidential information passing through them. These fears are seeing a divide growing between western and eastern nations, potentially giving rise to what experts are naming the ‘Splinternet.’  

But there you have it, a brief foray into the fascinating undersea underbelly of the internet’s infrastructure. As well as all the geopolitical manoeuvring, flexing, and chest-beating that goes along with it. It’s always fascinating how something so seemingly straightforward could have so many factors at play. These cables may top anything local can provide in speed (even the nbn™), but if you are looking to get away from the wires and get the best wireless can provide, why not look to see if Pentanet Fixed Wireless is available in your area?