Submarine Cables: The Invisible Backbone of the Internet

When we think of the internet, we often imagine something ethereal and intangible, like Wi-Fi, 5G, or even satellite constellations. Yet, 95% of the world's data travels through over one million kilometers of submarine cables laid across the ocean floor. These essential yet often overlooked infrastructures form the true backbone of our global communication.
In this article, we’ll explore how these cables—ranging from the first telegraph connections to today’s ultra-fast fiber optic networks—have become so crucial to modern society.

History
The first attempt at transoceanic communication dates back to 1857, with a telegraph cable laid on the Atlantic seabed between Canada and Ireland. Signals took 17 hours to cross the ocean, and unfortunately, the cable lasted less than a month. This initial effort highlighted the challenges of creating reliable submarine connections.
It wasn’t until 1956 that the first submarine telephone cable was successfully laid, followed by the first internet connection cable in 1988.
Today, submarine cables can reach lengths of up to 20,000 km, enabling ultra-high-speed connections. For instance, the “Marea” cable between Spain and the USA offers a capacity of 160 Tbit/s, while the recently deployed “Blue” cable, which passes through Liguria, connects France to Jordan across the Mediterranean with a capacity of 400 Tbit/s..

Submarine Cable Technology

Submarine transport infrastructures consist of three primary elements (commonly referred to as “wet” infrastructure in telecommunications jargon):

• Submarine Cables: Modern cables are built to withstand extreme conditions. They contain thousands of fibers protected by multiple layers of materials, such as polymers and metallic armors, allowing data to travel at the speed of light while maintaining a stable signal even at great depths.
• Repeaters: Placed at regular intervals along the cable, typically every 40-80 km, repeaters amplify the optical signal to counteract losses caused by distance.
• Landing stations: These are the points where cables come ashore. After traversing thousands of kilometers under the sea, cables connect to coastal landing stations, where they are linked to terrestrial backbones, extending connectivity to local network infrastructures.

The laying of submarine cables is a complex operation.
The installation of submarine cables is a complex operation. It involves cable-laying ships equipped with high-precision positioning systems that deploy cables, while specialized technicians join them at the repeater points.
Route optimization and careful handling during cable deployment and splicing are key to completing projects within the planned timeframe (typically taking years) while ensuring high transmission performance and minimizing latency.

Potential Risks

It’s essential to safeguard submarine cables, as several factors can make them vulnerable:

• Marine Environment: Saltwater can corrode the materials that make up the cables.
• Natural Events: Volcanic activity, hydrothermal vents, and earthquakes can create fractures in the seabed where cables rest.
• HUman Activity: Ship anchors, fishing nets, and maritime traffic, especially near coastal areas, pose risks. Moreover, cables have also been targeted for sabotage, as in Egypt in 2013, underscoring their strategic importance for global communication.

Damage to a submarine cable can have significant repercussions, disrupting connections between entire continents and requiring costly repairs.

The Future of Submarine Cables

Installing submarine cables is an extraordinarily expensive endeavor, costing between €30,000 and €90,000 per kilometer and easily running into millions of euros depending on distances. These investments are typically borne by consortia of major telecommunications operators, often supported by governments and investment funds. Since the early 2000s, such funds have seen opportunities in reselling or leasing sections of cables to smaller operators and companies needing private, high-speed, low-latency connections.
Recently, major technology players like Meta, Google, Amazon, and Microsoft—where data is a strategic resource—have directly financed the construction of proprietary cables. While the era of massive investments from the early 2000s (when €25 billion, equivalent to €43 billion today, was spent between 1999 and 2001) is over, forecasts suggest a new wave of investments to meet the growing demand for data, which has become the true currency of the 21st century.
An essential driver of this development is the rise of artificial intelligence (AI) services, which require the transfer of vast amounts of data between data centers worldwide. As a result, submarine cables are critical not only for global communication but also for supporting advanced infrastructures and digital transformation. Their technological evolution and expansion will be crucial for the future of connectivity.

Retelit’s Role

Retelit plays a strategic role in the submarine cable market.
It is a telecommunications operator active in the submarine cable sector, both as a member of AAE1 (Asia-Africa-Europe-1) and as a technological partner for the development of landing stations on Italian territory (e.g., in Bari for AAE-1 and in Savona for IEX).
Additionally, it provides low-latency international transport services, both terrestrial and submarine, connecting Europe, Asia, the Middle East, and the USA.
As a member of AAE1, Retelit participates in the consortium that built and operates one of the main submarine cables connecting Southeast Asia to Europe via Egypt, spanning 25,000 kilometers.
AAE1 connects Hong Kong, Vietnam, Cambodia, Thailand, Malaysia, and Singapore, as well as Myanmar, India, Pakistan, Oman, the United Arab Emirates, Qatar, Yemen, Djibouti, Saudi Arabia, Egypt, Greece, Italy, and France. The AAE-1 cable system leverages state-of-the-art 100 Gbps transmission technology, with a minimum global capacity of 40 Tbps.
One of the unique features of AAE1 is that, while it terminates at two Points of Presence (PoPs) in Singapore, it extends further into Asia via various terrestrial routes through Thailand, connecting Vietnam, Cambodia, and Hong Kong. This design enables AAE1 to achieve some of the lowest latencies between Hong Kong, India, the Middle East, and Europe.

Insight provided by Luca Cavobianchi - Product Marketing Retelit