Introduction – why global connectivity matters?
In today’s extremely connected and specialised global world trade, business workflows and supply chains critically depend on global connectivity. Think about your last online purchase, financial transaction or interaction on social media, all of this goes through globally connected networks.
Additionally, science and research – be it medical science, natural sciences like physics, or climate research – depend on the sharing and exchange of massive amount of data.
Currently, the cumulative volume of global data traffic is estimated to be 33 exabytes (33*1018 bytes) per day [1].
This means that global connectivity is a critical part of today’s global society and a cornerstone and anchor point of trust, the importance of which can’t be overemphasized these days when old allies change and start to behave unreliably.
The technologies for connectivity
Most people use their mobile devices, handhelds to connect. This makes a deceiving perception that seamless and persistent connectivity is over the air wirelessly for most cases. Which is true, until the first so called mobile basestation or tower. From then on, invisible to the average user the connection is via fibre optic cables that connect the base stations to the core of the network and to large data centres where the data and services are hosted. In turn, these data centres are interconnected by large capacity optical cables with multiple fibres, each carrying multiple connections using different optical wavelengths. Globally, there are 570 undersea cables in service (and more than 80 planned) that connect those networks and data centres, creating a global fabric of interconnections [2]. This global network carries 99% of the data traffic and is owned by network operators and large service provider companies like Google, and makes up the by now critical digital superhighway.
Vulnerabilities and incidents
Let me cite here a picture of the global undersea cable network (figure1). As it can be seen, due to geographics, the global interconnectivity network is very concentrated at certain points. Cable routes follow very similar paths and so-called landing points of the cables are shared, or are very near to each other. Such areas, choke points can be easily identified on the global map even by untrained eyes. Most notably, such an area is the Red Sea – which also happens to be one of the busiest shipping routes of the world.
Recently, there were a number of reports in the news regarding various incidents concerning some of those undersea optical communication cables. Let us examine systematically the threats and technologies for this critical global connectivity infrastructure.
Figure 1: ITU global undersea cable network (© ITU)
Natural disasters
Undersea optical cables are vulnerable to natural disasters, such as earthquakes and volcanic eruptions. One such incident was in 2006, when an earthquake South of Taiwan severed eight major cables at 18 points, effectively cutting all East-West communication at this point, so traffic had to be routed the other way around the globe to circumvent the disruption. Repairing those connections took nearly two months and involved 11 (!) ships.
A more recent incident is the volcanic eruption at Tonga. Many would remember the spectacular pictures in the news and the video from space about the massive eruption, which among other damage caused severed all connections to the outside world from Tonga.
Man made incidents
By far the most common accidents and damages to submarine cables are caused by fishing. Fishing trawlers pull nets and heavy gear – so called trawl doors – helping to keep the mouth of the net open either in midwater, but often directly at the bottom, effectively ploughing the seafloor (causing massive environmental damage).
Clearly, such gear can severe a communication cable, even if the cable is lightly buried in the seafloor. Therefore, fishing (as well as anchoring) is restricted in the vicinity of cables, but the enforcement is difficult, and human errors can occur [3][4].
Another, recent incident demonstrates a slightly different type of threat. Houthi forces attacked a ship on the Red Sea forcing the crew to drop anchor and abandon ship. The stricken ship dragging its anchor severed three cables carrying a large volume of traffic between Europe and Asia and thus caused a major disruption.
There has been several other incidents and disruptions reported in the news, most notably from the Baltic Sea. It might be that none of those can be fully ascertained as arson or sabotage, but the blowing up of the Nord Stream gaspipe in that region was clearly a deliberate attack on an underwater infrastructure.
Figure 2: Trawling – Source: Marine Stewardship Council
Installing and repairing undersea communication cables
Laying undersea communication cables started more than 100 years ago. It involves loading a long section of the cable onto a special cable laying vessel, and deploying the cable on location.
This method of laying cables is essentially the same, as it was 100 years ago. Obviously, the cables have changed, the physical transport medium in the cables and the construction of the cables also changed, and most importantly, their data carrying capacity has improved several orders of magnitude.
What has not improved, or changed much less dramatically is that the process of deploying those cables is time consuming and relatively slow. Furthermore, the fleet of specialized vessels capable of laying cables is aging and relatively small [5]. According to the International Cable Protection Committee [6], there are only around 60 of those specialised cable ships in the world. This fleet is also ageing and not being renewed at a sufficient rate. Only eight of those 60 ships are younger than 18 years, with most between 20 and 30 years old, and 19 ships are over 30 years old. This ageing fleet also need more time out for being maintained and repaired – their availability is not ideal. Overall, ships are generally booked long time ahead for jobs, laying new cables and scheduling the repair of disruptions need to be tightly scheduled and managed [7]. Recently we see a trend of adding more specialized, smaller vessels that can’t install new cables on long routes, but can pick up damaged cables and repair them. Nevertheless, this picture remains rather grim and demonstrates how vulnerable the global undersea connectivity infrastructure is and constrained by the limited capacity available for fixing, repairing [8]. Let me cite here an example that demonstrates what the above means in practical terms. In case of the Tonga incident – already mentioned earlier –, with best effort and goodwill, the main international connection cable was repaired in less than one and half months, but the fixing of a smaller, internal cable between the islands took 18 (!) months.
Figure 3: Orange Marine cable layer vessel – René Descartes (© ORANGE Marine)
Alarming capabilities to disrupt undersea communication infrastructures
An alarming recent publication reports about new deep-sea cable-cutting capabilities developed by China [9]. The uncrewed submersible vehicle by Chinese researchers can operate up to 4000 (!) m depths, and is equipped with a sufficiently high revolution (1600 rpm) diamond coated cutting blade that is effective against steel-reinforced armoured undersea cables. The device was developed by the China Ship Scientific Research Centre (CSSRC). Although originally developed for civilian salvage and seabed mining, the device’s dual-use potential raises serious concerns, as it looks to be an ideal tool, a weapon for systematically severing undersea communication cables. The threat is definitely real.
Improving the resilience of the infrastructure
In light of the very clear threats to the global connectivity infrastructure and the current geopolitical situation it is really imperative to improve the resilience of that infrastructure [10], and the way to achieve this is through further geographic diversification. One option investigated in recent years in the EU-Japan relation is the deployment of an undersea communication cable following the so far not explored and utilised arctic route. Climate change and advancement of technology make this a viable option, and it comes with one specific advantage. There is no fishing taking place in ice covered waters, hence the risk of the most common damaging activity is non-existent. (At the same time, in case of an incident repairs might need to wait until the Arctic summer, and even then, the assistance of an ice-breaker might be necessary.)
Space communications
In light of the persisting vulnerability of the global undersea infrastructure attention turned onto securing, or at least backing up connectivity for the most critical traffic via satellite communications. In recent years the global satellite constellation of StarLink demonstrated the potential and capabilities of non-terrestrial networks also to the general public. It has to be noted though that satellite communications can’t provide the same capacity as undersea cables – it lags behind by 2-3 orders of magnitude in capacity. Nevertheless, being able to communicate, albeit in a restricted way is still far better than losing connection altogether. Regarding this aspect, the NATO pilot project HEIST (short for hybrid space-submarine architecture ensuring information security of telecommunications) is looking into first and foremost to ensure that when cables are damaged and fail operators can locate the position of the disruption precisely and quickly in order to initiate fast repair. Secondly, to become able to divert high-priority traffic to alternative routes, and specifically to satellites in orbit [11] .
The European satellite constellation IRIS2
Here, at this point it is important to highlight IRIS², the new EU Secure Satellite Constellation, an Infrastructure for Resilience, Interconnectivity and Security by Satellite [12]. The European Commission has signed the concession contract (effectively a public-private partnership agreement) for the IRIS² multi-orbital constellation of 290 satellites with the SpaceRISE consortium in December 2024, but the process has started much earlier. The SpaceRISE partnership will develop, deploy, and operate the European Union’s new system, which represents a significant step towards Europe’s sovereignty and secure connectivity. The constellation is planned to become operational by 2030.
Conclusions
In light of the many recent incidents reported regarding undersea cable cuts this paper reviewed the technologies and solutions used in global connectivity, their respective roles, and the threats that are pertinent specifically to the undersea communication cable systems. Regarding the threats our survey was constrained to the physical layer.
The EU continues to support submarine networks and connectivity infrastructure [13].
Figure 4: Submarine cable structure (Source: Oona Räisänen, Submarine Cable Cross-Section 3D Plain, Public Domain, accessed November 30, 2021, https://commons.wikimedia.org/wiki/File:Submarine_cable_cross-section_3D_plain.svg.), Notes: (1) Polyethylene, (2) Mylar tape, (3) Stranded metal (steel) wires, (4) Aluminum water barrier, (5) Polycarbonate, (6) Copper or aluminum tube, (7) Petroleum jelly, and (8) Optical fibers
Acknowledgment and Disclaimer:
Part of this work was funded by the EC INPACE project (Grant Agreement number 101135568).
The views expressed herein are solely by the author.
References:
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