[bluGill]

Until one runs out of IPv4 addresses. I think it is safe to say that Amazon, Facebook, and google each have data centers big enough that IPv4 address management is a headache. I believe Facebook is internally IPv6 (that is server to server communications - their public space obviously has IPv4, and their desktop space can get by with NAT and IPv4 if they want to). Google has done enough promoting of IPv6 that I think they are the same. I'm not sure what AWS is - they sell server time so they have more need for IPv4 to the servers (google cloud has the same concerns)

[gekonipjawfjn]

AWS is IPv4 internally. You know how they promote that their regions are independently isolated and to be the most redundant, you should be in 2 regions. Well, a big part of that was they were running out of IPv4 addresses in their multi-region interconnected network and they were too cheap to upgrade so they started creating every new AWS region in its own separate IPv4 network to save address space in the main one.

[ArchOversight]

Facebook only has IPv4 at the edge. Everything internal is IPv6.

[samoa42]

suggests that ipv6 is here to replace the rfc1918 space but "the internet" largely remains ipv4.

the high v6 penetration in mobile networks likewise suggests that smartphones are generally not a part of the network as much as dedicated leaf nodes that require no inbound connections.

[p1mrx]

There's a difference between "IPv4 is only present at the edge" and "only IPv4 is present at the edge".

I think Facebook is doing IPv4+IPv6 at the edge, and IPv6-only internally.

[ArchOversight]

You are correct. Facebook has done multiple presentations where they showed how they have a IPv4 load balancers/translation layer at the edge that converts everything to IPv6... but native IPv6 is well, just that, native.

There's no translation layer needed.