Lower Indian Ocean Network (LION): connecting islands in the Indian Ocean
The Lower Indian Ocean Network (LION) submarine cable is a 1060-kilometer fiber-optic system linking three key locations in the Indian Ocean:
Sainte Marie in Réunion,
Terre Rouge in Mauritius, and
Toamasina in Madagascar. Operational since 2009, according to GeoCables data, the cable is owned by Mauritius Telecom, Orange, and Orange Madagascar. It serves as a critical link for regional telecommunications, enabling faster and more reliable internet connectivity between these islands and the broader global network.
What makes LION particularly interesting is the scarcity of publicly disclosed technical details about its design and capacity. While the cable's operational status is confirmed, information about its fiber count, supplier, and technology remains unavailable in public sources. This lack of transparency is not uncommon in the submarine cable industry, especially for systems serving smaller regional markets. Additionally, live latency measurements show significant variability, highlighting the complexity of real-world internet routing and the impact of terrestrial infrastructure on end-to-end performance.
Quick facts
| Cable name | Lower Indian Ocean Network (LION) |
| Length | 1060 km |
| Ready for service | 2009 (GeoCables database; no conflicting dates surfaced) |
| Owners | Mauritius Telecom, Orange, Orange Madagascar |
| Status | In service |
| Design capacity | Not disclosed |
| Fiber pairs | Not disclosed |
| Supplier | Not disclosed |
| Technology | Not disclosed |
| Landing points | Sainte Marie (Réunion), Terre Rouge (Mauritius), Toamasina (Madagascar) |
Route
The LION cable connects three strategic landing points in the Indian Ocean: Sainte Marie in Réunion, Terre Rouge in Mauritius, and Toamasina in Madagascar. This corridor links two island nations and a French overseas territory, providing critical connectivity for local businesses, governments, and residents. Réunion serves as a key node for connecting to global networks via other submarine cables, while Mauritius and Madagascar benefit from improved international bandwidth and reduced latency compared to satellite-based systems.
Why it was built and what it carries
The LION cable was built to address the growing demand for reliable and high-speed internet connectivity in the Indian Ocean region. Before its deployment, these islands relied heavily on satellite connections, which are slower and more expensive than fiber-optic cables. By providing direct links between Réunion, Mauritius, and Madagascar, LION reduces latency and enhances the capacity for data transmission, supporting economic growth, digital inclusion, and improved access to online services.
While the cable's specific design capacity remains undisclosed, its primary function is to carry internet traffic, voice communications, and other data services between the connected locations. It also serves as a regional gateway to international networks, leveraging connections from Réunion to larger submarine cable systems.
History: what can be established
The LION cable was recorded as ready for service in 2009, according to GeoCables data. No conflicting dates have surfaced in industry sources, suggesting general agreement on its operational timeline. The cable's ownership structure includes Mauritius Telecom, Orange, and Orange Madagascar, indicating a collaborative effort among regional telecom operators to improve connectivity.
Publicly available information does not provide details about the cable's construction process, supplier, or technology. However, standard industry practices for submarine cable deployment likely applied, including seabed surveys, cable laying by specialized ships, and burial in shallow waters to protect against damage.
Capacity and technology
The design capacity of the LION cable has not been disclosed in public sources, nor are details available about its fiber count or technological specifications. Without operator documentation, attributing specific figures would be speculative. It is reasonable to assume that the cable was designed to meet regional demand at the time of its deployment, with potential for upgrades as technology advances.
Latency: the physics
Theoretical calculations show that light propagation over the 1060-kilometer wet segment of the LION cable would take approximately 5.2 milliseconds one-way, resulting in a round-trip time (RTT) floor of 10.4 milliseconds. However, live measurements from remote probes reveal significantly higher RTTs, ranging from 72.2 ms to 288.5 ms for paths involving Terre Rouge and Toamasina. This discrepancy reflects the impact of terrestrial infrastructure, routing inefficiencies, and additional delays introduced by terminal equipment and network configurations.
For example, the measured RTT between Cape Town and Sainte Marie (54.9 ms) and between Singapore and Sainte Marie (204.1 ms) suggests that the cable plays a role in connecting these locations indirectly, but the latency is influenced by intermediate networks.
Redundancy: what happens if it breaks
If the LION cable were to experience a fault, connectivity between Réunion, Mauritius, and Madagascar would rely on alternative systems or satellite links. While specific redundancy options for this corridor are not listed in the GeoCables database, Réunion is connected to other submarine cables, such as SAFE and METISS, which could mitigate disruptions. Repair logistics would follow standard industry practices, including fault localization, deployment of cable repair ships, and restoration of service.
Bottom line
- The Lower Indian Ocean Network (LION) is a 1060-kilometer submarine cable connecting Réunion, Mauritius, and Madagascar.
- Operational since 2009, it is owned by Mauritius Telecom, Orange, and Orange Madagascar.
- Technical details such as design capacity, fiber pairs, supplier, and technology have not been disclosed publicly.
- Live latency measurements show significant variability, far exceeding the theoretical RTT floor of 10.4 ms.
- Redundancy options for the corridor are not explicitly documented, but regional alternatives likely exist.