RoderickBeck

Machine learning is by definition a black box. Nonlinear statistical models with huge numbers of parameters to be estimated.

Facebook is building a 480 Tbps subsea cable connecting Spain to South Caroline. Some of the capacity in the form of fibre pairs and spectrum will be sold to carriers in the wholesale market. It is a 24 pair system using the latest and greatest spatial division multiplexing technology. Traditional coherent optics technology is limited to 6 or 8 pairs max.

No, Facebook is building a cable from the East Coast to South Africa and then from South Africa to India and forward to Australia. The final leg is to the US. What Tagare did is take the W shaped network and add branching units. Those branching units have not been confirmed by my contacts. The general shape of the network has been confirmed.

Actually the RTD ranges from 58.9 ms to close 80 milliseconds depending on the cable. That is assuming the end points are Secaucus NY4 and Slough LD4. Those re data centers.

AI data centers are not latency sensitive because their purpose is model estimation, not service delivery.

But they still need fibre optic connnections to move immense amounts of data.

They are private assets. And really it is impossible to protect them. How do you protect 1.5 million kilometers of spaghetti?

And far less bandwidth. Microwave is used for ultr-low latency trading. But most financials ride subsea cables like everyone else.

Maintenance and repair is third party. Subcom, Alcatel, etc.

It is about expense. It is cheaper to own than to rent if your traffic is great enough. And ownership provides control and better management.

I think that cable was SWM5. It ended up 15 kilometers from the original burial trench. This is why deep burial is recommended, but adds expense.

Correct. Modulation is encoding the bits in different aspects of the light wave. The better the modulation scheme, the more expensive is the division multiplexing equipment.

Not really. I know of no cases where optical amplifiers posed a barrier to upgrading. Ciena and Infinera have been able to upgrade cable capacity by several X.

Optical amplifiers simply boost the signal. A photo is absorbed and then re-emitted with more power, but the same frequency and phase.

There is no optical/electrical/optical conversion.

It is called a spectrum sale. Quite common today where Google, Facebook, Microsoft, and Amazon are the banks behind most new high capacity systems.

The throughput can be dramatically increased by upgrading the DWDM kit. The optical amplifiers in the water are technologically agnostic. The fibre can be a gating factor. For a while fibre with chromatic dispersion compensation was used and that actually limits the ability to upgrade the cable using modern coherent optics.

- The author.

In international waters you do not permits. Only for landing the cable and in the territorial waters.

- The Author.

Not speculation in terms of the general path of the cable. What is speculation is the number of branching units.

The article is accurate. I am the author. My sources are/were involved in designing the cable.

As noted the cable connects the US East Coast to South Africa and then heads to India and continues on to Australia before the home stretch to the States. We even know the number of fibre pairs, 16. It is a spatial division multiplexing system.

Hi,

I am the author. The article is not speculation. I know from sources inside Facebook that the cable will head Southeast from the US East Coast directly to South Africa. From there it heads directly to India. From India to Australia. From Australia to the US West.

What is speculation are the branching units. It is natural to add branching units to aggregate traffic to more countries. But I have no confirmation.

Regards,

Roderick.