This Industry Viewpoint was authored by Greg Varisco, COO, Aqua Comms
The lines on a submarine cable map that represent subsea cables crossing the oceans signify the various routes of the world’s data, video and voice communications. But if you were to put your ear closer to the map, you might be able to hear the story of how these systems come about and what goes into the planning process. Modern subsea cable systems are designed to meet the exponential surge in bandwidth demand from carriers, global data centers, financial services companies, and cloud and content providers, including Web-scale providers and Over-the-Top (OTT) companies that require exceptional reliability and performance. Subsea cable systems need to be refreshed approximately every twenty years, allowing owner-operators to apply lessons learned and upgrade the optical network and management systems to obtain cost-efficiencies and reduce risk. Risks associated not only with reliability, but also security. Over time, older methods that are responses to past incidents become prohibitively expensive to support, so it becomes necessary to utilize new technologies that have built-in protection methodologies.
A New Way of Building Networks
The major changes in subsea cable system design are due to the deployment of coherent-based networks. These newer technologies include advances in both physical components and architecture. Changing the type of glass cores (G.654), which lower linear impairments, for example, attenuation, as well as deploying higher power repeaters with no chromatic dispersion compensation — since these impairments are handled in the Submarine Line Terminating Equipment (SLTE) on either end — make it possible to utilize even more advanced modulation techniques, such as 8 and 16 Quadrature Amplitude Modulation (QAM). Advancements with soft Forward Error Correcting (FEC) algorithms provide greater reach because operators no longer place the SLTE equipment in the cable landing stations, lowering and even eliminating certain operational costs. Now, the system has the optical margin to support direct data center to data center lighting by placing the SLTE in locations throughout the U.S. and Europe.
A Shark Ate My Google
Coordinating closely with clients, subsea cable operators strive to mitigate and minimize a host of risks that submarine cable systems face. Certain dangers, such as the culinarily misguided shark, are relatively improbable due to subsea cables’ high tensile strength armored sheaths. Some risks are theoretical but worrisome, including Russian submarines, which would have to plunge to deeper depths to sabotage the cable system due to certain cable’s increased burial. Other vulnerabilities are unavoidable, for example, the earthquake and tsunami in Japan that severed many of Verizon’s subsea cables and required several weeks to repair in order to restore the country's full connectivity. And some risks are frustratingly all too common: ship anchors dropped in shallow water cause about 70% of all breaks.
Securing the World’s Communications
All subsea cable systems face risks, however real or hypothetical. Transatlantic cable owner-operators generally lay cable to traverse the minimum length of shallow water along the Continental shelf on both landfall approaches. It’s also necessary to avoid major fishing grounds and shipping anchorage areas that are known to expose subsea cables to damage. Aqua Comms’ America-Europe Connect (AEConnect) system, for example, was designed with security and reliability as key areas of focus, and its route, deeper burial and additional armoring address specific vulnerabilities. Moreover, if a cable system is built with deep water branching units that enable it to extend its capabilities to additional landings, this increases both the coverage and security of the system.
Security Isn’t Just Physical
Modern subsea cables are designed to utilize emerging technologies, such as Software-Defined Networking (SDN), to support bandwidth-intensive applications. By securing the signalling channel with a whitelisting protection methodology, fewer resources are spent on ensuring subsea cables are protected against every known vulnerability, thus enhancing the resiliency of the network even further. This ensures that global organizations can take advantage of resilient and secure connectivity at predictable costs.
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