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.
About the Ningbo-Zhoushan Cable Cable System
Ningbo-Zhoushan Cable: A Short-Distance Submarine Link in China
The Ningbo-Zhoushan Cable is a submarine telecommunications cable connecting two locations in eastern China: Mamu and Xiepu. Spanning a modest 35 kilometers, it is owned and operated by China Telecom and has been recorded in the GeoCables database as ready for service (RFS) since 1999. The cable is listed as active and in service, although public information about its design capacity, fiber pair count, supplier, and specific technological details remains unavailable.
What makes this cable interesting is its short length and its role in connecting two geographically close areas, Ningbo and Zhoushan, which are part of Zhejiang Province. While many submarine cables serve international or long-distance domestic routes, the Ningbo-Zhoushan Cable is a rare example of a short-distance link, likely built to support regional connectivity and reliability. However, the absence of detailed public disclosures about its technical specifications leaves certain aspects of its operation and significance unclear.
The Ningbo-Zhoushan Cable connects Mamu and Xiepu, two locations within Zhejiang Province, China. Mamu is situated near Zhoushan, an island city known for its maritime economy and proximity to the East China Sea. Xiepu lies near Ningbo, a major port city and industrial hub. The cable traverses a short marine distance, likely under shallow waters, given the geography of the region. This route is part of a broader effort to enhance connectivity between mainland China and the Zhoushan Archipelago, which relies heavily on infrastructure for communication and commerce.
Why it was built and what it carries
The Ningbo-Zhoushan Cable was likely constructed to address the growing need for reliable telecommunications between Ningbo and Zhoushan. These two areas are economically significant, with Ningbo serving as one of China's busiest ports and Zhoushan being a center for maritime industries and tourism. The cable may carry a mix of voice, data, and internet traffic, supporting both residential and commercial users in the region. Its short length suggests it plays a role in regional rather than national or international connectivity.
History: what can be established
GeoCables records the Ningbo-Zhoushan Cable as ready for service since 1999. There is no conflicting information from industry sources regarding the RFS year, so 1999 is the most reliable date available. Publicly accessible documentation about the cable's construction, suppliers, or upgrades over time is scarce, making it difficult to trace its full operational history or any enhancements that may have been made since its deployment.
Capacity and technology
The design capacity of the Ningbo-Zhoushan Cable is not disclosed in public records, nor is information about its fiber pair count, supplier, or specific technology. Without operator documentation, it cannot be determined whether the cable has undergone upgrades to increase its capacity or improve its performance. Given its short length, it is reasonable to assume that the cable employs standard submarine cable technologies, but attributing specific details without evidence would be speculative.
Latency: the physics
The theoretical one-way latency for light propagation over the 35-kilometer wet segment of the Ningbo-Zhoushan Cable is approximately 0.2 milliseconds, while the round-trip time (RTT) floor is around 0.3 milliseconds. These calculations are based on the speed of light in fiber, which ranges from 200,000 to 204,000 kilometers per second. However, real-world latency will be higher due to additional factors such as land-based network tails, terminal equipment processing, and routing inefficiencies. No live measurements of latency are currently available for this cable.
Redundancy: what happens if it breaks
If the Ningbo-Zhoushan Cable were to experience a fault, redundancy within the corridor would depend on alternative infrastructure, which is not detailed in the available records. In general, short-distance cables like this one are easier to repair than longer international cables, as the shallow waters and proximity to shore simplify logistics. Repairs typically involve deploying specialized cable ships to locate, retrieve, and fix the damaged segment. However, the availability of backup routes or other cables in the region is unknown.
Bottom line
The Ningbo-Zhoushan Cable spans 35 kilometers and connects Mamu and Xiepu in Zhejiang Province, China.
Owned by China Telecom, it has been recorded as ready for service since 1999.
Public information about its design capacity, fiber pairs, supplier, and technology is not disclosed.
Theoretical latency over the wet segment is approximately 0.3 milliseconds round-trip, but real-world latency will be higher.
Its role appears to be regional connectivity between economically significant areas, Ningbo and Zhoushan.