On an island this means losing the submarine link; on the mainland traffic can still go over land.
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Counted: other international cables landing in the same country (domestic cables between points of one country are not a way out), other cables at landing points within 50 km, and whether the country has land links. Not counted: cable capacity, operator contracts and satellite. Use as a first look at dependence, not as a statement of what would happen.
The Haikou-Beihai Cable is a submarine telecommunications cable owned by China Telecom, connecting Beihai in Guangxi Province to Lingao in Hainan Province, China. With a recorded ready-for-service (RFS) date of 1999, this cable is listed as in service and spans a distance of 198 kilometers across the Qiongzhou Strait. Despite its relatively short length, the cable plays an important role in regional connectivity.
What stands out about the Haikou-Beihai Cable is the scarcity of publicly disclosed information about its technical specifications, such as design capacity, number of fiber pairs, and supplier details. This lack of transparency is not uncommon for older submarine cables, particularly those serving domestic routes within China. Additionally, there are no live latency measurements currently available for this cable, leaving its real-world performance open to interpretation based on theoretical physics.
The Haikou-Beihai Cable spans the Qiongzhou Strait, linking Beihai in Guangxi Province to Lingao in Hainan Province. This corridor lies entirely within Chinese territorial waters, making the cable a domestic route. Beihai is a coastal city known for its port facilities and proximity to major shipping lanes, while Lingao is located on the northern coast of Hainan Island, an area increasingly significant for tourism and economic development. The cable's route is relatively straightforward compared to transoceanic systems, as it traverses a narrow strait.
Why it was built and what it carries
The Haikou-Beihai Cable was likely constructed to enhance connectivity between Hainan Island and mainland China. As Hainan's economic importance grew, particularly with its designation as an international tourism and trade hub, reliable telecommunications infrastructure became essential. The cable supports domestic internet traffic, voice communications, and potentially private network services for businesses operating in the region. However, specific details about its traffic composition and usage remain undisclosed.
History: what can be established
The GeoCables database lists the Haikou-Beihai Cable's ready-for-service date as 1999. If industry sources suggest a different year, this discrepancy would need to be explored further, but no alternative dates have been surfaced at this time. The cable's operational history appears to have been stable, as it is still listed as in service. Its longevity reflects the durability of submarine cable systems, which are designed for decades of use with periodic maintenance.
Capacity and technology
Publicly available data does not confirm the Haikou-Beihai Cable's design capacity, number of fiber pairs, or supplier. Without operator documentation, attributing these parameters would be speculative. Given its domestic scope and 1999 RFS date, it is reasonable to infer that the cable was built using technology available at the time, such as optical fiber systems capable of supporting multiple wavelengths. However, advances in submarine cable technology since then may have led to upgrades, which are also not publicly disclosed.
Latency: the physics
The theoretical one-way latency for light propagation over the cable's 198-kilometer length is approximately 1.0 milliseconds, assuming a speed of 200,000 to 204,000 kilometers per second in fiber. The theoretical round-trip time (RTT) floor for the wet segment is approximately 1.9 milliseconds. Real-world latency measurements would be higher due to additional factors such as land-based network tails, terminal equipment processing, and routing inefficiencies. No live latency measurements are currently available for this cable, leaving its actual performance unquantified.
Redundancy: what happens if it breaks
If the Haikou-Beihai Cable were to experience a fault, redundancy would depend on alternative routes within the corridor. Other cables connecting Hainan Island to mainland China could provide backup capacity, though their specific configurations and ownership structures are not detailed here. Repair logistics would follow standard industry practices, involving cable ships equipped with specialized tools to locate and fix the fault. Given the cable's domestic scope, repair operations would likely be coordinated within China's regulatory framework.
Bottom line
The Haikou-Beihai Cable is a 198-kilometer domestic submarine cable connecting Beihai and Lingao in China.
Owned by China Telecom, it has been in service since 1999 according to GeoCables data.
Technical specifications such as design capacity, fiber pairs, and supplier are not publicly disclosed.
Theoretical latency over the wet segment is approximately 1.9 ms RTT, but real-world performance is unknown.
Redundancy would rely on alternative cables in the region, though specifics are unclear.