The internet depends on a network of submarine cables no thicker than a garden hose, yet these tiny conduits carry the vast majority of global internet traffic. As digital demand explodes and new cables proliferate, cable route engineers face an increasingly complex challenge: finding space on the seafloor for new systems while maintaining the safety and reliability of existing infrastructure.
In this episode of the TeleGeography Explains the Internet podcast, James Porter, a cable route engineer at Alcatel Submarine Networks (ASN), highlights this growing crisis. His research reveals that in several key regions worldwide, the seafloor has become so congested with cables that designing compliant new routes is becoming nearly impossible.
Here are some key takeaways from the conversation.
Subscribe to get more episodes:
Apple | Amazon | Spotify | Stitcher | TuneIn | Podbean | RSS | YouTube
The International Cable Protection Committee (ICPC) provides crucial guidance for the submarine cable industry through its recommendations for planning new cables near existing systems. The most critical standard requires new cables to maintain a separation distance of three times the water depth from parallel existing cables. This seemingly simple rule exists because cable maintenance still relies on century-old technology—dropping a grapnel hook to recover cables from the seafloor.
"The reason we have a congestion issue is because we need to be able to maintain those cables," Porter explains. "In deep water, where we've just surface laid them, the method of recovery is the same as it's been for the last 80 years. It's just a grapnel, so we have to just hook them."
This separation requirement becomes problematic in deep waters. At 2,000 meters depth, cables must be positioned 6 kilometers apart. When dozens of cables traverse the same region, the mathematical reality quickly eliminates available routing options.
Porter's analysis identified three critical congestion zones where cables are forced into narrow corridors by a combination of physical geography and geopolitical constraints. The eastern Mediterranean, the Gulf of Oman, and waters off Japan represent the worst-case scenarios—deep, congested areas where separation requirements are largest and routing options most limited.
These chokepoints emerge from predictable patterns. Cables naturally follow population centers and economic hubs, creating convergent routes. Physical geography compounds the problem through narrow straits like Gibraltar or the Bab-el-Mandeb, where cables have limited routing options.
Geopolitical factors further restrict available space. In the Red Sea, difficulties obtaining permits from Eritrea force all cables through Yemeni waters, concentrating infrastructure in areas now subject to deliberate attacks. Similarly, Iranian territorial restrictions push Gulf cables into Omani waters, effectively halving available routing space.
Perhaps the most solvable aspect of seabed congestion stems from poor information sharing within the industry. Cable installers often work with incomplete pictures of existing infrastructure and planned projects, leading to inefficient use of available seafloor space and commercial risks.
"It's really hard to develop a new route when we don't have the full view of what's already on the seabed or what is already in development," Porter notes. Multiple companies may target the same optimal routing areas without coordination, discovering conflicts only after expensive surveys are complete.
The solution requires overcoming competitive instincts. While companies understandably protect sensitive route information, the industry would benefit from better data sharing mechanisms, potentially through non-disclosure agreements and coordinated working groups.
As submarine cable demand continues growing—driven by AI applications requiring ultra-low latency and expanding global connectivity needs—the seabed congestion problem will only intensify. Porter advocates for several mitigation strategies: targeting older systems approaching end-of-life for closer routing, identifying low-risk areas where separation requirements might be relaxed, and crucially, establishing better communication protocols between installers and cable owners.
The industry also needs clearer notification systems when cables are retired, freeing up valuable seafloor real estate. With many cables from the early 2000s internet boom approaching their 25-year lifespans, this coordination could provide critical relief in congested areas.
How do we understand and address the challenges facing the submarine cable maintenance sector? That's what Mike Constable of Infra Analytics and TeleGeography’s Lane Burdette and Alan Mauldin lay out in this landmark report. Download the report here.
Watch episode 1 in this cable series, or check out the key takeaways here.
Watch episode 2 in this cable series. Here are the key takeaways.
Watch episode 3 in this cable series. Get the key takeaways here.
Where are submarine cable stations located? What is the average number of cables per CLS? This analysis by Lane Burdette summarizes the data from TeleGeography’s new cable landing station (CLS) database. View and save the report.
Data and analysis on long-haul networks and the undersea cable market, with forecasts of international bandwidth supply, demand, prices, and revenues. Take a look at the platform here.
Data and analysis on international internet capacity, traffic, service providers, and pricing, with forecasts of IP transit service volumes, prices, and revenues by country and region. Check out how it works.