EllaLink

On June 1, 2021, a signal left Sines, Portugal — a quiet fishing port on the Alentejo coast — and arrived in Fortaleza, Brazil, sixty-two milliseconds later. For the first time in the history of the internet, a European packet reached South America without touching North American soil. The cable that made this possible is EllaLink: 6,200 kilometres of fibre optic cable crossing the Atlantic Ocean floor, navigating one of the planet's most formidable geological obstacles, and carrying with it the political weight of a continent that had decided it wanted its own route.

The Post-Snowden Cable

Before EllaLink, every bit of data between Europe and South America took a detour through the United States. A video call from Lisbon to São Paulo would travel north to New York or Miami, hop across domestic American networks, then head south again — a 15,000-kilometre journey for two cities separated by less than 8,000 kilometres of ocean. The routing added latency, but that was the smaller problem.

In June 2013, Edward Snowden revealed that the NSA's PRISM programme and its British counterpart TEMPORA were tapping submarine cables landing on US and UK soil. For Brazil — a country whose president's personal phone had been monitored — this was a political crisis, not just a privacy concern. President Dilma Rousseff cancelled a state visit to Washington, addressed the UN General Assembly demanding internet governance reform, and fast-tracked the Marco Civil da Internet, Brazil's landmark internet bill of rights.

EllaLink was not born from Snowden — the project had been discussed since 2012 — but Snowden gave it urgency and political funding. The European Commission backed it through the BELLA programme (Building the Europe Link with Latin America), and the cable became infrastructure for the Copernicus Earth observation programme, the GÉANT research network, and RedCLARA, the Latin American academic backbone. EllaLink is not just a commercial cable. It is a political statement rendered in glass and polyethylene.

Why the Cable Cannot Go Straight

Open a map and draw a line from Sines to Fortaleza. The great-circle distance is approximately 5,800 kilometres. EllaLink's actual cable length is 6,200 kilometres — about 7% longer than the geometric shortest path. Some of that extra length comes from the branch segments to Madeira, Cape Verde, Nouadhibou, and Casablanca. But a significant portion exists for a reason that has nothing to do with geography and everything to do with physics: the cable must obey its minimum bend radius.

Every submarine cable has a mechanical limit on how sharply it can curve. For modern armoured fibre cables of the type used by EllaLink, the minimum bend radius during installation is typically 1.5 to 2.0 metres — roughly ten to twenty times the cable's outer diameter. In operation, once the cable settles on the seabed, the constraint relaxes slightly to about 0.75 to 1.0 metres. Violate this limit, and the consequences range from increased signal attenuation to micro-fractures in the glass fibres that may not manifest for months or years.

On a flat ocean floor, bend radius is rarely a concern. The cable plough cuts a shallow trench, the cable settles in, and the geometry is gentle. But EllaLink does not cross a flat ocean floor. Directly in its path lies the Mid-Atlantic Ridge — the longest mountain range on Earth, stretching 16,000 kilometres from the Arctic to the Southern Ocean, entirely underwater.

Crossing the Mid-Atlantic Ridge

The Mid-Atlantic Ridge is a divergent tectonic boundary where the Eurasian and African plates pull away from the South American plate at a rate of about 2.5 centimetres per year. The result is a volcanic mountain chain rising 2,000 to 3,000 metres above the surrounding abyssal plain, with a central rift valley that can drop another 1,000 metres. At the latitude where EllaLink crosses — roughly 10°N to 20°N — the ridge is complicated by transform faults: perpendicular fractures that offset the ridge axis by tens of kilometres, creating sheer walls and narrow valleys.

For a cable route survey — the multi-year marine investigation that precedes any submarine cable installation — the Mid-Atlantic Ridge is a problem of angles. A cable dropping from 4,000 metres depth to a ridge crest at 1,500 metres over a horizontal distance of just 20 kilometres encounters a seabed gradient of about 7 degrees. That may sound shallow, but at 7 degrees the cable must follow the slope precisely, and any abrupt change in gradient — a volcanic pinnacle, a fault scarp, a lava flow — can force a bend tighter than the minimum radius.

The solution is route optimisation: the survey vessel maps the seabed with multibeam sonar, identifies terrain features that would force the cable below its bend specification, and plots a path that goes around them. Every detour adds length. Every added metre of cable adds latency — light in glass travels at roughly 200,000 km/s, so each extra kilometre adds 5 microseconds to the one-way transit time. The 400 kilometres of "excess" cable in EllaLink's route represent, in part, the accumulated cost of respecting the bend radius across the roughest terrain in the Atlantic.

The Anatomy of a Bend

Why does bending matter so much? A modern submarine cable is a precision optical waveguide surrounded by layers of protection. At its core are the optical fibres — typically 4 to 16 fibre pairs in a modern system — each a glass strand 125 micrometres in diameter, carrying data as pulses of light via total internal reflection. The light stays inside the fibre because the core glass has a slightly higher refractive index than the surrounding cladding. This works as long as the fibre is reasonably straight.

When the fibre bends, a phenomenon called macro-bend loss occurs. Light that would normally be totally internally reflected instead strikes the core-cladding boundary at an angle too shallow for reflection and escapes into the cladding. The tighter the bend, the greater the loss. At the minimum bend radius specified by the manufacturer, the additional loss is designed to be negligible — typically less than 0.1 dB. Below the minimum radius, losses increase exponentially. At extreme bends, the cable may still function immediately, but the mechanical stress creates micro-cracks in the fibre that propagate over time, eventually causing a fault that is extraordinarily difficult to localise — because it does not manifest as a clean break but as a gradual, position-dependent attenuation that drifts with temperature and ocean current.

This is why route surveys spend months mapping every contour of the seabed. A cable that lasts 25 years — the standard design life — must never, at any point along its route, rest in a geometry that exceeds the bend specification. The Mid-Atlantic Ridge is not the only challenge (continental shelf edges, submarine canyons near landing points, and areas of known seismic activity all require similar attention), but it is the most sustained one. EllaLink crosses approximately 400 kilometres of ridge terrain, and every metre of that crossing was plotted to avoid bend violations.

Seven Landing Points, Three Continents

EllaLink is not a simple point-to-point cable. Its route includes branch units — passive optical switches on the seabed — that split the signal to intermediate landing stations:

Each branch landing introduces its own bend-radius challenges at the continental shelf. The transition from deep ocean (3,000–4,000 m) to shallow coastal waters (under 200 m) occurs over just a few tens of kilometres, and the cable must navigate submarine canyons, fishing grounds (requiring burial deeper than trawl depth), and port approaches. At Praia, Cape Verde, the volcanic island shelf drops steeply to abyssal depth within 10 kilometres of shore — one of the most abrupt transitions on any cable route.

What Our Measurements Show

GeoCables monitors EllaLink using RIPE Atlas probes at both endpoints. The data reveals a striking asymmetry:

The Fortaleza-to-Sines direction is remarkably stable: 29 consecutive measurements between March 2 and March 26, 2026, all clustered within a 2-millisecond window around 139.6 ms. This kind of consistency — a standard deviation under 1 ms across nearly a month — indicates a clean, dedicated path with no congestion or route flapping.

The Sines-to-Fortaleza direction tells a different story. For weeks, the target IP in Fortaleza was classified as "shared" — meaning it is hosted at a facility connected to the cable landing area but reaches the measurement endpoint through additional network hops. These measurements consistently returned approximately 200 ms, suggesting the signal was traversing domestic Brazilian routing infrastructure after reaching the continent.

Then, on April 12, 2026, the target was reclassified as "verified" — and the RTT dropped to 65.2 ms.

The Physics Check

The theoretical minimum round-trip time for EllaLink:

Cable length: 6,200 km
Speed of light in fibre: ~200,000 km/s (refractive index ≈ 1.468)
One-way propagation: 6,200 ÷ 200,000 = 31.0 ms
Round-trip theoretical minimum: 62.0 ms

The verified measurement of 65.2 ms from Sines corresponds to a 1.05× multiplier — meaning only 5% overhead above the speed of light in glass. If confirmed by subsequent measurements, this would make EllaLink one of the most efficient submarine cables in our database, approaching the theoretical floor more closely than Tonga Cable (1.26×), Marea (1.95×), or Equiano (2.5×).

The 139.6 ms from Fortaleza gives a 2.25× multiplier — consistent with approximately 77 ms of terrestrial routing overhead added on top of the cable transit itself. The cable is fast. The networks at its endpoints add the delay we measure.

This asymmetry is itself a lesson in submarine cable measurement: what we observe is always the sum of the subsea fibre and the terrestrial networks at each end. EllaLink's glass may carry data across the Atlantic in 31 milliseconds each way, but the "last mile" — or in Brazil's case, the last thousand kilometres to São Paulo — determines the round-trip time that users actually experience.

A Cable Built to Bend

EllaLink entered service on June 1, 2021 — delayed by nearly two years from its original target, partly by COVID-19 and partly by the complexity of laying cable across the Mid-Atlantic Ridge. The cable ship that performed the final installation had to manage continuous tension adjustments as the cable descended into and ascended from the ridge terrain, ensuring that at no point did the cable touch down with a bend radius below specification.

Five years into its design life, EllaLink carries data for the European and Brazilian research communities, provides Madeira and Cape Verde with their most modern international link, and gives Mauritania an alternative to the aging ACE cable. It has recorded zero anomaly alerts in our monitoring system — no threshold breaches, no unexplained RTT spikes, no service-affecting events.

The cable's reliability is, in a sense, the reward for all those extra kilometres. Every detour around a seamount, every gentle curve plotted to respect the bend radius, every additional metre of cable laid to avoid a volcanic outcrop — they all translate into a system that sits comfortably within its mechanical envelope, year after year, carrying light across the roughest terrain in the Atlantic at very nearly the speed of physics.