I wonder if we should design infrastructure that is resilient to cables being cut, I’m pretty certain everything would break right now if the Atlantic cables were cut. Does anyone know of an easy way to test this? Would cloudflare or AWS go down for example? What about my local bank?

We do have resiliency - the internet reroutes around these cuts l. Knock out every Atlantic cable and traffic from NY to London would route via LA and singapore.

I see this all the time on traffic from far east to Europe when a Red Sea cable dies, and I’ve seen it from India to Europe too (and seen traffic rerouted via South Africa and up the west coast a fair bit)

Latency is higher, but on the whole things continue to work. Until there’s enough damage - problems tend to be if you cut enough that cables and the routers they are connected to start to bottleneck.

What kind of resiliency are you hoping to achieve? For most routes, there are many dozens of cables starting at many different locations and taking many distinct paths across the ocean. The companies using these cables take great pains to ensure redundancy for critical paths: they'll validate minimum distances between the cables, ensure that they have a variety of landing points, ensure that they have enough spare capacity to handle a certain number of cables all being out for repair simultaneously. Alternatives to cables would be either land-based wireless (radio, point-to-point microwave) or satellite, both of which have much lower throughput capabilities and also are vulnerable to sabotage of transmission/receiver locations.

While the number of cables is not large enough to put it out of the reach of many nations, it's also something that no group with the capability of doing it would really want to do: it's a surefire way to invite retribution from basically the rest of the world, while not really achieving much militarily: armies almost invariably have their own communication systems (satellite, microwave, transoceanic fiber whose location is secret, etc).

Hypothetically you could test this by forcing your connections to avoid certain data centers... how you would do this, I'm unsure. It's been a while since I've taken a course on it but I swear CompTIA Network+ covered this

Sure, which of the 24 Atlantic cables are you going to cut with their 5-15 day repair time estimates? Or maybe the 20+ routing the other way around the Earth. (See map linked above)

I know of a way to test it…

But realistically, I would think the US/Americas would be approximately fine. Most, if not practically all, services people on the NA continent use are based in the US from both a corporate and technical perspective. The command+control stuff for distributed systems is probably in the US.

Across the pond(s), yeah, I’d expect more disruption.