Subsea Cables & Internet Infrastructure

Candle is one of the more interesting Intra-Asian cables to go live over the next several years. It is the first 24 fibre pair system to serve this region. Total transmission capacity is 570 Tbps. This makes it one of the highest capacity cables on the planet. Like Apricot, Candle avoids the South China Sea due to Beijing's territorial claims and permitting demands. The main trunk links the inseparable couple of Tokyo and Singapore with branches into the Philippines, Taiwan, Indonesia, and Malaysia. Consortium leaders include META, Softbank, and Telekom Malaysia. This project, like Apricot, exemplifies the geopolitics of American-Chinese rivalry. Hyperscalers avoid China and HK and exchange traffic at neutral Singapore. However, the routing is shorter than Apricot because Candle is deployed at the edge of the South China Sea as opposed to a long detour around Indonesia and up the East Coast of the Philippines. Like Apricot, Candle offers physical diversity to the usual suspects mak...

The Echo cable is a 12 fibre network directly linking Singapore to California with with a Guam branching unit. Bifrost, the other cable connecting Singapore and the US, also lands in Bifrost. I believe each cable effectively serves as backup for the other because traffic can be rerouted at Guam. Both cables are only 12 fibre pairs due to the great distances involved. Its design capacity is 260 Tbps. A key feature of both Bifrost and Echo is they bypass the South China Sea even though it is part of the shortest path between Singapore and the US West Coast. Hence Chinese permits are avoided, resiliency is improved since most Intra-Asian traffic traverses the South China Sea, and the cable is more protected from Chinese tapping or attack. However, it does come as a price. The cable must be buried quite deep through the shallow Indonesian waters to minimize fishing boat or anchor damage. And Indonesia is quite slow to issue permits for new subsea cables. So two cables likely...

JAKO is a high capacity cable connecting Korea and Japan via a Busan, Korea, and a Fukuoka, Japan landing. Busan is a major Korean cable landing spot. Nine cables including JAKO land in Busan. The cable's consortium consists of Microsoft, Amazon, Arteria (important Japanese back haul carrier), and the Korean Dreamline company. Dreamline is a Korean carrier that provides tower services, metro and long haul connectivity. It is increasingly common for hyperscalers to team up with competitive carriers in Asia because the regional PTTs are viewed as difficult, slow to make decisions, and too concerned about protecting their home turf. Uncooperative is hyperscaler diplomatic language to describe the telecom incumbents. NTT is an exception to this generalization. Obviously this cable reflects Microsoft and Amazon's cloud and AI ambitions. No public information is available on the number of fibre pairs. Given the fixed costs associated with cable deployment and rapidly growing traffic,...

Apricot is one of the most exciting Southeastern Asian cable projects to be RFS next year. In fact, it is the first subsea network to be truly physically diverse from the South China Sea. The 12 fibre pair main trunk's end points are Singapore and Tokyo, but the path completely bypasses the South China Sea by detouring through Indonesia and up the Philippines' East Coast. This increases latency, but makes Apricot the natural complement for any cable system like ADC or SJC2 that goes through the South China Sea. Obviously the latency is higher than the usual suspects, but most buyers need resilient networks to keep their jobs. Apricot lands in Singapore, Indonesia, the Philippines, Taiwan, Guam, and Japan. The cable system has military value as it links Taiwan to the Guam, the latter being the US military command center for the Western Pacific. Its routing around the South China Sea also makes it less vulnerable to sabotage. Design capacity was originally intended to be 211 Tbps...

Although most subsea cables with Singapore POPs land at Singapore, some do not, and these exceptions are the keys to better uptime for your Layer 1 network. Five fibre pair AAE1 lands at a Penang, Malaysia CLS that has a fully diverse fibre ring for automatic route protection into Singapore. Each side of the fibre ring uses a separate bridge to cross the Malaysian/Singapore border. One side of the ring terminates at the older of the two Global Switch data centers and the other at SG3. So AAE1 neither lands at Singapore nor uses any of the Singapore cable landing stations. This is one reason why AAE1 is a 'must' for network capacity buyers. Other reasons include low latency for the Marseille/Singapore end points and relatively good pricing due to the system's high capacity. Bay of Bengal Gateway also lands in Penang, Malaysia, but my understanding is that it and AAE1 use different cable landing stations. However, I have not seen backhaul maps so I cannot clai...

Building a resilient Layer 1 network where Singapore is a major POP is very difficult. Most subsea cables land in Singapore via designated sea lanes with four to five cables per lane. This increases the risk of a dragged anchor taking many cables. Although over the last ten years there have been few or none such incidents, a network planner is judged on future performance and proper risk management. Moreover, most subsea cables land at subsea cable landing stations (only 4 in total) serving many other cables. So dividing traffic among several cables is not good enough if resiliency is the goal. Tuas CLS: Apricot, Asia Direct Cable, Bifrost, I-2SEA, I2I, IAX, Indigo West, INSICA, MIST, MVISTA, PEACE, SEA-H2X, SMW4, SMW5, SMW6, SJC, & UMO. Tanna Merah: SEAX-1, BJC2, BJC3, & ASC. Changi North: AAG, BSCS, CANDLE, C2C, Echo, JAKABARE, MIC-1, RISING 8, TGN-IA, TGN-INDICOM, & TIS. Changi South: APG, ASE, C2C, MATRIX, & SJC2. Cable landing diversity is extremely hard to achieve...

These two Subco-owned cable systems have experienced ongoing outages that started August 8th. Each has a shunt fault located very near the other in the Perth cable protection zone. This zone extends from shore to a depth of 2000 meters and is over 100 kilometers long. These protection zones can backfire because their width is usually just a nautical mile. So the cables are packed together like sardines and if a ship drags its anchor, then multiple outages are pretty much guaranteed. It raises the question of whether cable protection zones are really a good idea since the level of shipping pretty guarantees cable damage. In a way, cable protection zones violate the principle of resiliency via physical diversity. The most likely suspect in this case is a ship that dragged its anchor across the two cables and damaged the sheath protecting the power conductor from water. A ship has been identified that was in the area at the time the outages began. Cable repairs are slated to be complete A...

If you have ever heard someone say they bought a quarter or half fibre pair, it means they bought the right to use a slice of laser spectrum to create transport services. Think of spectrum as clay and optical waves as the finished product. The spectrum seller places a filter on a fibre pair that ensures the buyer only gets the purchased frequencies. A quarter fibre pair means they get 25% of the pair's total usable spectrum. Similarly, for a half fibre pair.  In general, the minimum commercial purchase is 560 Gigahertz. The amount of usable bandwidth depends on the modulation or encoding scheme. Complex encoding schemes generate more zeros and ones than simple ones. And they cost proportionally more. Using standard Ciena gear, you can squeeze about 2.5 terabits of usable capacity out of the 560 Ghz allotment. Below is the basic topolgy. Richard Norris of Ciena (2025 Suboptic Spectrum Working Group) created the slides.  Spectrum is like any other service. You can lease or buy i...

Lasers produce coherent light. This means the electromagnetic waves have the same frequency, move in the same direction, and their phase repeats in a regular pattern. The practical implication is that the laser light remains in a tight, focused band as opposed to spreading over time. This prevents the signal strength or optical power from rapidly diminishing. However, in telecommunications, coherent optics is more than just laser light. It has two key ingredients, advanced modulation schemes that use combinations of amplitude and phase to create higher bandwidth. The other component are digital processing chips (DSPs). Laser light is subject to nonlinear errors due to chromatic and polar dispersion. The DSPs can detect these errors and recover the original pristine signal. Digital signal processing detects nonlinear errors using mathematical algorithms called forward error correction. 

A fibre optic subsea cable is encased in a polyethylene sheath. Most damage due to fishing trawlers, current abrasion, and anchors occurs in water depths 1,000 meters or less. Hence cables laid or buried in shallow waters are usually single or double armored to protect them. The armor consists of galvanized or stainless steel wires wrapped around the white polyethylene layer. Galvanized steel wire has a zinc coat that resists salt water corrosion. While armor does protect against abrasion and small mechanical forces, it is not strong to prevent the cable being torn by sea floor trawler net or a dropped or moving anchor.

A shunt fault is damage to the insulation around the power conductor that all subsea cables require for undersea optical amplification. It causes an electric short. They are most common in the deep sea where the cable lies exposed on the sea floor as opposed to near shore where burial is routine. Abrasion caused by deep sea currents that rub cables against sharp surfaces like rocks are the usual suspects. Depending on the extent of the abrasion, a shunt fault may or may not cause an outage. It depends on the ability of off-shore power facilities to compensate for a partial loss of voltage. When I was worked at Hibernia Atlantic, our cables experienced shunt faults that did not disrupt service. A cable ship would be dispatched to fix it. Below is a shunt fault on Subco's Oman/Australia cable. You can see the power burns on the eroded insulation. 

An Irish company, MDM, whose founding members have done a lot of design work for hyperscalers, has announced it is building two Trans-Atlantic cables in addition to its Pisces project that will connect Ireland to Europe. The estimated construction cost is $500 million. The network is a classic dual ring design where the Northern cable lands at Galway and on Long Island. Now there are several Long Island cable landing stations and MDM already operates one in Galway. So MDM may use these existing facilities for its project. In contrast, the Southern cable is expected to land at a new CLS on Ireland's South Coast. On the US side it will land in New Jersey where it will probably use the existing Wall Township CLS. The fibre pair will probably 16.  I have concerns about this project because there is nothing to indicate it is fully funded. In fact, the last carrier financed and led project across the Atlantic was Aquacomms' AEC-1 cable that went live in 2016. EXA recently purchased ...

Two year term.

It turns out that the CS Sovereign, a Global Marine ship whose home port is Portland, UK, is sailing down the West African cost to Abidjan to fix WACS. Why was the Sovereign chosen when it is so far away? Every cable system has one or two storage depots where fibre is kept for repairs. WACS spare fiber and other repair supplies are kept at Brest, France. Now Orange Marine has a cable ship, the well known Léon Thévenin, at anchor in Capetown, South Africa. But if the supply depot is in Europe, a nearby cable ship becomes useless. It all makes eminent sense because WACS connects both the UK and Lisbon to West Africa and the cable was laid from the UK to Lisbon and down the West African coast. So the starting point for deployment was Europe and hence that is where the spare supplies are located. However, this is a severe logistical mistake since most WACS outages occur between Senegal and Congo, not in European waters.

The cable ship repair permit has been granted. It is expected to arrive off Abidjan on July 22nd. The 2Africa cable will be the first repaired despite its outage being limited to the Cote d'Ivoire branch. WACS repair is expected to begin at the month's end. The ASN Ile D'Ouessant cable ship left Capo Verde last week and will arrive in the Gulf of Guinea this Wednesday.

NTT and Mitsui Leasing have teamed up together with fibre optic cable manufacturer Sumitomo Corporation to fund a 16 fibre pair subsea cable costing $500 million. Design capacity is 320 Tbps. This is the second project on which NTT Data and Mitsui Leasing have cooperated. The high capacity 20 fibre pair Juno cable was the first project. It is unusual to see a large incumbent player like NTT undertaking a subsea cable project with a non-telecom company as co-owner. But the advantages are clear. Mitsui will contribute cash, but not play a major role in design, vendor selection or wholesale commercials. So it not only reduces NTT's risk by sharing funding requirements, but it gives NTT a free hand in decision making. One lesson that has become perfectly clear is that large carrier consortiums increase the likelihood of deployment delays and lengthen the entire planning cycle because decisions require consensus. Moreover, the consensus requirement makes it difficult for new approaches...

MRC: $32.5K. A point: Most Mumbai DCs. Z point: SG3.  Cable: IAX.

A consortium consisting of TATA Communications, Lightstorm, Microsoft, and Singtel just announced a new 16 fibre pair subsea network tailored to serve the AI data center markets in Hyderabad, Singapore, and Kuala Lumpur. It includes two Indian landings, one in Southern Chennai and another at Machilipatnum, the latter being the shortest path to Hyderabad. Both Hyderabad and Lumpur host large numbers of data centers equipped with GPUs for rent to estimate AI large language models. Conversely, Singapore is a distribution point for estimated AI models. What is sometimes called AI inference. Both space and power in the city state are too limited and expensive for AI model estimation. Besides the Singapore and Indian landings, there will likely be a cable branch landing in the Malaysian province of Selangor, chosen because it is the shortest way to reach Kuala Lumpur. Public information on the new system is sparse, but it is also likely that cable will include be extended to Hyderabad and Ch...

A turbidity current is the likely culprit for the WACS trunk outage. The same holds true for the 2Africa Ivory Coast branch failure. The Taiwan earthquake of December 2006 is instructive in this regard. The 22 knocked out cables failed in sequence over the course of several hours. So the sheer force of the earthquake was not responsible. Instead, the seismic event caused sediment to begin moving down the undersea slope of Taiwan's continental shelf. This was not a gentle slope, but rather the steep sides of the Kaoping subsea canyon, which is 4 kilometers deep. As the chart shows, cables went dark in sequence radiating from the epicenter outward as this undersea tidal wave traveled down the sides of the subsea canyon. The turbidity current traveled at speeds ranging from 3.7 meters per second to 5.7 meters (roughly 20 kilometers per hour). The sequence of events suggests there were at least 2 and probably turbidity currents involved.  It is probably not a coincidence ...

ISPs in Ghana are reporting their 2Africa waves are up and running. So 2Africa's main trunk appears untouched. Hence the Cote d'Ivoire outage must be due to a branching segment fault. It is thought a turbidity wave caused the damage. This is a powerful surge of water, debris, and mud that can wash away the sediment covering buried cables and snap them like toothpicks. I call it an underwater Tsunami. It is triggered by an undersea avalanche due to an earthquake or a flooding river like the Congo pouring into the Atlantic. For example, the 2006 Taiwanese earthquake caused a turbidity current that tore apart 22 cables off the country's Southeast coast. This current traveled several hundred kilometers and reached speeds as high as 72 kilometers an hour. It is not clear what caused the turbidity surge off Abidjan. What we do know is that there is a large subterranean cavern, Le Trou Sans Fond, at Abidjan's doorstep. It was likely involved.  The last few days Cote d'Ivoi...