What each country and landing point keeps if National Digital Transmission Network (NDTN) goes down. A calculation from our cable and landing-point database, not a forecast.
Every landing point of this cable has another cable within 50 km.
No alerts from our monitoring on this cable in the last 180 days. Events feed →
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.
Live Performance
105
measurements
7
probes
94
days monitored
244.7
ms avg RTT
0
anomalies
Monitored from 2026-07-11 through 2026-10-14 - live ICMP round-trip time measurements via our monitoring probes. All values below are recomputed daily from raw probe data. ✓ No anomalies detected in the monitored period.
Measurement sources
Probe
Location
Samples
Avg
Min-Max
Last seen
#6410 own probe
Sao Paulo BR
34
344.3 ms
319.2-706.8
2026-10-14
own probe
Almaty KZ
34
329.9 ms
266.1-357.0
2026-10-14
#6568 own probe
Singapore SG
24
56.0 ms
51.7-64.5
2026-10-14
#6487
control probe
9
47.2 ms
31.2-58.6
2026-08-20
#6427 own probe
Sydney AU
2
247.6 ms
212.6-282.6
2026-09-20
#7062 own probe
Cape Town ZA
1
217.5 ms
217.5-217.5
2026-07-11
own probe
Tbilisi GE
1
289.1 ms
289.1-289.1
2026-07-11
About the National Digital Transmission Network (NDTN) Cable System
National Digital Transmission Network (NDTN): A regional submarine cable in the Philippines
The National Digital Transmission Network (NDTN) is a submarine cable system connecting four key locations in the Philippines: Dumaguete, Iloilo City, Lucena, and San Jose. Spanning approximately 1400 kilometers, it is owned and operated by the Telecoms Infrastructure Corporation of the Philippines (TelicPhil). First recorded as ready-for-service in 1999, the cable remains listed as in service today, playing a role in domestic telecommunications.
What stands out about NDTN is the scarcity of publicly disclosed technical details. Its design capacity, fiber pair count, supplier, and specific technological features are not documented in available sources. This lack of transparency makes it difficult to assess its performance relative to more modern systems, but it is clear that NDTN contributes to connectivity within a country with a challenging geography of islands and archipelagos.
Quick facts
Name
National Digital Transmission Network (NDTN)
Length
1400 km
Ready-for-service year
1999 (GeoCables database value; no conflicting dates surfaced)
Owner
Telecoms Infrastructure Corporation of the Philippines (TelicPhil)
The NDTN connects four landing points within the Philippines: Dumaguete, Iloilo City, Lucena, and San Jose. These cities are spread across different islands, emphasizing the cable's role in bridging geographic divides in the archipelago. Dumaguete is located on Negros Island, Iloilo City is on Panay Island, Lucena is in the Quezon Province on Luzon Island, and San Jose is on Mindoro Island. This route facilitates inter-island communication, which is essential for a nation composed of over 7,000 islands.
Why it was built and what it carries
The NDTN was built to enhance domestic telecommunications in the Philippines, providing a reliable connection between key regional hubs. While specific data on its traffic is not publicly available, it likely carries voice, data, and internet services for residential, commercial, and government users. Its role is particularly important in a country where terrestrial fiber networks are limited by geographic constraints.
History: what can be established
The GeoCables database records the NDTN as ready-for-service in 1999. No conflicting dates have been identified in industry sources, suggesting this year is widely accepted. However, details about its construction, financing, and initial deployment remain elusive. The cable's continued operation indicates regular maintenance and upgrades, though specifics are not disclosed.
Capacity and technology
Publicly available data does not confirm the design capacity, fiber pair count, supplier, or specific technology used in the NDTN. Without operator documentation, attributing these characteristics would be speculative. Given its age, it is likely that the cable has undergone upgrades to remain functional, but the extent and nature of these upgrades are unknown.
Latency: the physics
The theoretical one-way light propagation latency over 1400 km of fiber is approximately 6.9 milliseconds, with a round-trip time (RTT) floor of 13.7 milliseconds. However, real-world latency is higher due to factors such as land-based network segments, terminal equipment processing, and routing inefficiencies.
Live measurements from remote probes provide insight into end-to-end latency, though they include the full internet path rather than the cable itself. For example:
Sao Paulo -> Iloilo City: min 342.4 ms, avg 344.1 ms
Singapore -> Iloilo City: min 50.0 ms, avg 50.0 ms
Singapore -> Lucena: min 31.2 ms, avg 31.2 ms
Sydney -> Lucena: min 212.6 ms, avg 212.6 ms
These values reflect the combined latency of submarine cables, terrestrial networks, and routing.
Redundancy: what happens if it breaks
The NDTN's landing points are shared with other domestic cables, providing redundancy in case of outages. For example:
Standard industry practices for submarine cable repair include deploying specialized cable ships to locate and fix faults, which can take days to weeks depending on the severity and location of the issue.
Bottom line
The National Digital Transmission Network (NDTN) spans 1400 km and connects four Philippine cities.
Owned by Telecoms Infrastructure Corporation of the Philippines (TelicPhil), it has been in service since 1999.
Publicly disclosed data on its design capacity, fiber pairs, supplier, and technology is unavailable.
Theoretical latency is 13.7 ms RTT over the wet segment, but real-world measurements are higher.
Redundancy is provided by other domestic cables at its landing points.