Subsea Cables & Internet Infrastructure

In a recent interview META subsea engineers suggested their next project would be a 1 Petabit Trans-Atlantic cable. They pointed to three possible ways of accomplishing it: multicore fibre, use of the C and L spectrum bands, and 50 fibre pair SDM. Pros and Cons 1. Multicore is subject to cross talk. Right now the only multicore cable is the Taiwan-Phillipines-US cable scheduled to go live this year. A Google project with NEC as the vendor, it has two cores per fibre strand and 26 Tbps total per fibre strand or 13 Tbps per core. The challenge is cross talk. The light spills from one core to the other and vice versa. Obviously this distorts the signals and at high transmission rates the distortions become greater and greater and the signal-to-noise ratio disintegrates. The advantage of multicore fibre is that no redesigning of the optical amplifiers is required. Since everyone acknowledges that SDM alone is unlikely to surpass the half terabit mark, Google is obviously interested in mult...

As noted in my previous post, optical amplification allow light signals to be boosted without being first decoded into a digital representation. Optical-electrical-optical conversions go away. Hence the computer necessary for OEO conversions disappears. This in turn sharply improves the amplifier's reliability and life span. It also eliminates the conversion delay so end-to-end latency is improved. Finally, no computer means less cost. But these benefits are really secondary. More importantly, the advent of optical amplifiers led to a quantum leap in bandwidth that can be attributed to two related developments. The first is that optical amplifiers impose no transmission limits on computer technology. This means that we can lay a cable in the water and then upgrade it at regular intervals as Moore's law improves the ability of computers to process optical signals. Nothing on the wet side changes. Indeed, the introduction of digital processing allowed 10G wave subsea cables like ...

 A 1997 article celebrating how new optical amplifier technology will raise subsea cable output to an amazing five gigabits per second. It was a revolution at the time because the first optical fibre cable, TAT8, operated at 240 megabits. 😆

Layer 2 Switched Ethernet From Tokyo Data Centers To AWS Cloud 1. 10G; Layer 2 Pseudo Line Emulation Ethernet ; $775 MRC. 2. 100G; Layer 2 Pseudo Line Emulation Ethernet; $3800 MRC. Remarks: A. 802.1q frames. B. Jumbo framing available. C. See RFC 3985 to understand pseudo line emulation, which is basically a private line Ethernet service defined by a constant bit rate. D. Standard MTU size of 1522 bytes.

Picture below shows subsea amplfiers aboard a cable ship. They cost roughly $250K a piece, can support up to 40 Tbps, and are spaced every 70 kilometers or 42 US miles. These remarks apply to these specific amplifiers. As noted in Part 1 of this series, erbium doped fibre eliminated optical-electrical-optical (OEO) conversions for amplifiers. So the limiting factor of computer hardware involved in the conversions was eliminated. The result was a 'transparent' technology that placed no limits on submarine termination equipment upgrades. Subsea cables became highly scable because the amplifiers could easily handle higher throughput achieved via DWDM improvements. These amplifiers are tough buggers. They must withstand severe pressure at depths as great 8,000 meters for 25 years as well as nasty seawater corrosion. The amplifier hull is generally made of titanium or a special beryllium copper alloy, C17200, which conducts heat and electricity very well and is highly resistant to ...

Canada and US account for slightly over 45% of the world's IVP4 IP addresses. Europe is far less. Yet the 2025 budget for ARIN, the regional registry that serves the US, Canada, and Caribbean, is $28.8 million versus 41 million Euros for RIPE. If I use purchasing price parity to convert Euros to USD, and this is the correct approach, then the RIPE budget is 1.3*41 million Euros or $53 million USD. So RIPE's budget is almost twice the ARIN budget, yet their core functions are the same. The budgets are recouped via fees on IP addresses. It is plausible in my opinion that RIPE is feather bedding, which means it has a lot of unnecessary positions. There have been rumors for years that RIPE maintain a huge, but generally useless staff of community representatives. Let me add, that I have used ARIN to get /24s for an ISP client. The organization is highly efficient and professional. So is Arin underfunded and RIPE just the right size? Highly unlikely. Given the price pressures that I...