April 06, 2022
Fibre optic cable and landing stations: Your questions answered
Have you ever wondered how the internet works - more specifically, what infrastructure is in place to make it happen? Countries and continents are actually connected via terrestrial and subsea cables, forming a web of wires across the world. These data cables provide access to world-class bandwidth and high-speed internet connectivity to all corners of the globe.
Under the world's oceans, there are around 1.5 million kilometres of subsea cables. They connect to landing stations once they reach the shore. These stations serve as junctions, where subsea cables connect to terrestrial cable networks. Here are some frequently asked questions about fibre optic cables and related infrastructure.
What are fibre optic cables?
There are around 500 subsea fibre optic cables that are operational or under construction across the globe. Fibre optic cables are made up of thin glass fibre strands - some as thin as a human hair. They are insulated within a plastic casing and allow data to be sent at the speed of light over large distances.
Fibre optics vary from other forms of telecommunication cables in that they offer substantially higher bandwidth speeds across extremely long distances. These cables are the leading solution for data transmission around the world.
Just think; your computer or phone is connected to a small box in your home or office. This box sends a pulse of light that travels down the fibre optic cable, all the way to the nearest data centre, where it passes through and onward towards the coastal landing station. Here, it is routed through one of the subsea cables and heads off to another continent. This all happens within milliseconds.
What is the SEACOM cable?
The SEACOM Submarine Network stretches across Africa, assisting in economic development in the region. Kenya, Uganda, Tanzania, Mozambique, South Africa, Djibouti, Egypt, France and India are all physically connected by the SEACOM cable.
The cable was installed in July 2009 and upgraded to 1.5 Tbps capacity in 2018. It connects nine landing stations along the way, including Mtunzini (South Africa), Mombasa (Kenya), Dar Es Salaam (Tanzania), Maputo (Mozambique), Marseille (France) and Mumbai (India) (India).
What are landing stations?
Landing stations are the locations where subsea cables connect to the land. They're an important component of the fibre network's infrastructure. They convert the submarine cable into a terrestrial cable and distribute the data carried on the networks. The provision of power to the subsea cables is another important function of landing stations.
The SEACOM cable, for example, has a landing station at Mombasa where it reaches Kenyan shores. From here, the cable connects to data centres in the interior of the country. This provides the whole of Kenya with world-class internet connectivity.
How are subsea fibre optic cables made?
Fibre optic cables are usually surrounded by a protective material and housed within numerous layers of plastic and copper wires. "Repeaters" are connected at specific points along the underwater cables. They enhance the signal and are necessary for maintaining signal strength over long distances. These repeaters are powered by 10 000 volts of electricity, carried by copper wires within the cable casing.
How do fibre optic cables transmit data?
Fibre optic connections can transfer massive volumes of data via extremely thin wires. This is made possible by a technology called Dense Wavelength Division Multiplexing (DWDM). In layman's terms, this means that information is sent via more than one wavelength of light. Extremely high data speeds can be achieved by stacking multiple wavelengths. Fibre cables can carry roughly 100 gigabytes of data per second on average, with newer cables capable of up to 500 gigabytes per second.
Why do fibre optic connections occasionally fail?
Fibre optic cables are relatively tiny. The majority are about as thick as a garden hose. Within these, there are numerous glass strands that carry the pulses of light. Despite their small size, they are quite durable. However, they are sometimes damaged by various natural events, such as earthquakes and hurricanes. Engineers take great caution when laying cables to avoid seismic hotspots.
Human activity is another primary cause of cable outages. Trawler nets used in large fishing operations frequently tangle with subsea cables. Since cables near the shore are more vulnerable to damage, they are typically metal-plated and placed in dedicated trenches dug into the seabed.
Who owns fibre optic cables?
Cables were previously funded by governments or national telecom providers. Nowadays, they are more commonly owned by a consortium or group of owners, which may include governments, IT companies and other businesses. This means sharing the costs and expanding fibre availability around the world.
There has been a global shift in the funding of subsea fibre optic networks by technology companies, such as Google. These companies have been investing in the majority of underwater cable infrastructure in an attempt to accelerate infrastructure development.
Will we still use fibre optics in the future?
There is currently no alternative for high-performance connectivity that can match the all-rounded performance and affordability of fibre optic cables. Subsea cables are being installed at an exponential rate and this trend is only projected to continue to grow in the future.
SEACOM is a leading provider of world-class connectivity throughout Africa. Our international fibre network connects to other network providers' submarine cables, as well as our own. For businesses aiming to expand their digital portfolio, migrate to the cloud and provide better customer service, high-speed internet is a necessity. For more information or to get a quote for our connectivity solutions, email us at marketing@seacom.com or leave us a message.
SEACOM owns Africa’s largest network of information and communications technology (ICT) infrastructure, including fibre optic networks and subsea cables. We offer a wide range of industry-leading scalable ICT solutions for large companies that operate throughout the region.
SEACOM is privately owned - making it adaptable to the needs of the client. We are the preferred ICT and internet connectivity supplier for African enterprises. We can guarantee fast, reliable and secure internet and networking services at affordable prices.
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