Atlantic Crossing-1 (AC-1)

Overview

Atlantic Crossing-1 (AC-1) is a trans-Atlantic submarine cable system spanning approximately 14,301 kilometers. It connects the United States with three European nations: the United Kingdom, the Netherlands, and Germany. Commissioned in 1998, AC-1 was among the first modern, high-capacity undersea cable systems to cross the North Atlantic. Over the decades, it has undergone multiple upgrades to remain a vital part of the global internet infrastructure. Despite its age, AC-1 continues to serve as a critical link in one of the busiest data corridors in the world.

Currently owned and operated by Lumen Technologies, AC-1 exemplifies the longevity of submarine cable systems when combined with advancements in optoelectronic technology. Its operational license, renewed by the US Federal Communications Commission (FCC) in 2023, extends its service life until 2048. This renewal underscores its continued importance in trans-Atlantic connectivity, providing reliable data transmission between North America and Europe.

Route and Landings

AC-1 employs a ring topology with dual routes across the North Atlantic, known as AC-1 North and AC-1 South. This design enhances redundancy and resilience by enabling traffic rerouting in case of disruptions along one route. The system features four landing points:

• Brookhaven, New York, United States
• Whitesands Bay, United Kingdom
• Beverwijk, Netherlands
• Sylt, Germany

The Brookhaven landing in New York serves as the primary gateway on the US East Coast, connecting to three key European entry points. Whitesands Bay in the UK provides access to the British Isles, while Beverwijk and Sylt serve as critical hubs for continental Europe, linking the Netherlands and Germany, respectively. These landing points were strategically chosen to connect major economic and data exchange centers, ensuring robust trans-Atlantic communication.

The North Atlantic Ocean, a challenging environment for undersea cables due to its depth, cold temperatures, and potential for seismic activity, underscores the engineering achievements involved in AC-1's deployment. Its dual-route configuration further enhances reliability by mitigating risks associated with cable damage or outages.

Ownership and History

AC-1 was originally developed by Global Crossing, a pioneer in submarine cable systems. Today, it is owned and operated by Lumen Technologies, a major telecommunications provider. The cable's landing stations in Germany and the Netherlands are managed by Deutsche Telekom and KPN, respectively, reflecting a collaborative approach to international connectivity.

Since its launch in 1998, AC-1 has undergone numerous capacity upgrades, leveraging advancements in optoelectronic technology to increase its data transmission capabilities. Initially designed to handle lower capacities, the system now supports up to 5,600 Gbps on its southern route and 4,000 Gbps on its northern route. These upgrades have allowed AC-1 to remain competitive and relevant in an era of rapidly growing data demands.

In 2023, the FCC renewed AC-1's operating license for another 25 years, extending its service life until October 2048. This decision highlights the cable's enduring significance in the global telecommunications landscape and its ability to adapt to technological advancements over time.

What Our Measurements Show

Our live monitoring of AC-1 includes 370 measured corridors, providing valuable insights into its performance and reliability. The best recorded round-trip time (RTT) is 12 milliseconds, while the average RTT across all corridors is 117 milliseconds. These measurements reflect the cable's efficiency in transmitting data across the Atlantic, despite its age.

AC-1's dual-route design contributes to its resilience and path diversity, allowing traffic to be rerouted in the event of disruptions. This feature is particularly important in the densely trafficked trans-Atlantic corridor, where multiple submarine cables operate in parallel. Our probes also indicate that AC-1 plays a significant role in balancing traffic loads with neighboring systems, ensuring stable and efficient data flows between North America and Europe.

By tracking latency, route stability, and the impact of upgrades, our monitoring highlights AC-1's continued relevance as a backbone of trans-Atlantic connectivity. Its ability to adapt and integrate with newer systems makes it a valuable asset in the global telecommunications network.