Protecting our subsea cable network
Posted on January 12, 2017
4 min read
A vast network of underwater cables carry more than 99 per cent of international data traffic – and keep us all connected to the internet. So to keep people around the world connected, it’s vital these cables are safeguarded – although this presents a constant challenge.
Telstra operates the largest and most diverse subsea cable network in Asia Pacific, and we are constantly extending and enhancing this network to give our customers added resiliency should issues arise on a particular cable. This work has included building an overland cable in Taiwan, which avoids the earthquake prone Luzon Strait, and a highly resilient fibre based network in South Korea.
Protecting this infrastructure is a top priority for us, but a number of hazards in the area mean this isn’t always an easy task – luckily we have one of the world’s best team dedicated to meeting these challenges head on.
How you may ask? Let me tell you about our top three challenges and how we combat them.
Shallow shipping ports
Singapore and Hong Kong are two of the busiest – and shallowest – container ports in the world. Unfortunately, the combination of heavy traffic from big commercial vessels, shallow water and the sheer number of cables that connect to landing stations around these ports, does not bode well for our cables.
How we combat this: To avoid cable cuts, we have a team dedicated to monitoring the location of each container ship in relation to our cables through the ship’s Automatic Identification System (AIS). AIS provides information on each vessel, such as their unique identification number, position, course, and speed. If a ship gets too close, our team will make a call to the captain so they can adjust their course. On average, our team contacts 30 – 50 container ships a month.
This may sound like an unlikely challenge, but fishing vessels can cause damage when they drop anchor, particularly in the waters around Korea, China, and Taiwan where the water is shallow and the fishing activity is high. Likewise, drift nets can get entangled with our cables and pull them up from the seabed.
How we combat this: The good news is that regulated fishing vessels have GPS trackers so we can work with their crews to make sure they avoid our cables in popular fishing areas around China, Korea and Taiwan. The bad news is, unregulated fishing vessels operate under the radar and can be harder to track.
To help overcome the risks posed by unregulated fishing boats, we employ out of season fishing crews to monitor areas susceptible to regular damage. This not only helps to protect our cables, it also provides local fishermen with an extra source of income during their low season. And in areas where we have experienced regular damage from fishing, we have taken steps to bury our cables up to 3m below the seabed to avoid being hit by anchors.
The Asia Pacific region is prone to natural disasters, particularly typhoons and earthquakes. Being in close proximity to the Pacific Ring of Fire means there is lots of seismic activity – and deep ocean trenches – in the region. Earthquakes can disrupt the seabed and wash away our cables, while typhoons can cause mudslides and debris from the shore to wash into the ocean at speed – like an avalanche – and damage our cables.
Perhaps the worst damage caused by an earthquake was the one that happened off the coast of southern Taiwan on Boxing Day in 2006. The result was significant damage to major subsea cables in the area and the loss of internet connectivity to China and south-east Asia for two days, showing just how reliant we are on this infrastructure.
How we combat this: While there’s no way to completely avoid damage caused by natural disasters, there are some things we can do to lessen the impact. We have two maintenance ships on standby in Taiwan so we can deploy them without delay if our cables are damaged. These teams work to rebury cables that have been damaged or washed away.
We also recently built an overland fibre cable network in Taiwan to replace a major subsea cable in the earthquake prone Luzon Straight. This overland cable provides a unique redundancy link for traffic travelling from Japan and the US to Hong Kong and Singapore that other carriers cannot easily replicate.
These are just some of the challenges we deal with to protect our cables – and keep customers connected. There is also the multitude of regulations and stakeholders we need to deal with when working in these international waters and the odd case of theft (where people have been known to hook our cable to their boat and drag it to shore), but that’s a story for another day.