Broken European Underwater Cable Impacts Internet Connectivity Worldwide

Why it matters: Several undersea cables in southern France were cut overnight, making internet access globally unreliable. Engineers have fixed the broken link and an investigation has been launched. Russian submarines have been blamed for the Ukraine conflict, but investigators have not found evidence to support this hypothesis.

Serious incident involving submarine cables in the south of France

On Wednesday night, a serious incident involving an undersea cable in the south of France caused widespread internet connectivity problems. At least three fiber optic cables were cut at 20:30 (UTC), thus slowing internet access for users in Europe, Asia and the United States. Cloud companies are rapidly working to improve the backbone.

According to a report by cloud security firm Zscaler, an unexpected cable crash resulted in packet loss and increased latency for websites and applications traversing the affected path.

The company has identified three broken links: Marseille-Lyon, Marseille-Milan and Marseille-Barcelona. Zscaler has made routing adjustments to internet traffic where possible to mitigate the problem. However, in some cases, action is hampered by apps and content providers still using the broken link.

In a subsequent update released at 1:03:15 UTC, Zscaler confirmed that workers have fixed one of the affected links, resulting in lower packet loss and reduced latency for websites and internet applications.

The remaining links (probably Marseille-Milan and Marseille-Barcelona) were confirmed cut by live fiber test. However, the search operation to find the points of damage to the submarine cable is still ongoing.

An investigation has been carried out to gather evidence of the incident

As internet connectivity slowly returns to normal, investigations are underway locally and globally. French authorities have gathered evidence of the incident. Meanwhile, a non-cable breakdown in the UK has fueled wild speculation that the broken line may involve an unknown Russian saboteur.

The BBC has also reported that an undersea cable connecting the Shetland Islands to Scotland suffered damage around the same time as the incident in southern France. The break has left Shetland isolated from the rest of the world. The Shetland disconnection occurred while technicians were still working to restore another cable connecting the Faroe Islands to Shetland that was cut a week ago.

The risk of multiple incidents occurring in Europe's underwater fiber optic infrastructure is very small. The hypothetical scenario of a Russian submarine damaging global internet infrastructure seems a bit extreme. However, the geopolitical crisis at the time due to Russia's invasion of Ukraine raised concerns about the involvement of the Kremlin. Hopefully the case of damage to the European submarine cables will not happen again in the future.

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