After 30 years, with 99% of servers and devices having been designed decades after ip6 was created, half of traffic is still ip4.

If that’s not a failure I hate to see what is.

> If that’s not a failure I hate to see what is.

How would several billion smartphones be able to connect to the Internet without IPv6?

There isn't enough RFC 1918 (or 100.64.0.0/10) space for IPv4-only to be practical: Comcast—not even mobile—went to IPv6 because running their TR-069 management over multiple 10/8 became untenable.

IPv6 is making all sorts of things possible without most people realizing it.

Those phones are reaching half the internet via 64 gateways, no difference to reaching via 44 gateways.

> Those phones are reaching half the internet via 64 gateways, no difference to reaching via 44 gateways.

And how would they have gotten first-hop connectivity without IPv6?

Comcast added IPv6 many years ago on their wired ISP side because they ran out of IPv4 for TR-069 management, and they had way fewer subscribers (at least at the time) than many mobile telcos.

And that half of the Internet is also some of the most bandwidth intensive stuff: Youtube, Netflix, Instagram. The CG-NAT hardware costs of streaming would be huge.

The network isn't just the open internet. There's also the part inside the network. You can view Comcast as a black box that magically gets packets from one side to the other, but Comcast engineers can't.

If you want to run a single massive scale network sure. One of the costs of scaling that the majority don’t see

No reason you can’t carry IPv4 over any protocol you want. Multi tennant vxlans can carry whatever you want over your base network. Maybe an IPv6 underlay makes sense there, doesn’t really matter

Mostly they do carry IPv4 over IPv6 if they have vaguely newish equipment, otherwise they carry IPv6 over IPv4.

What's the par time for L3 protocol migrations on the Internet at its current size?

Bear in mind we've never done a project of this complexity and scale before. I'm sure we all wish it had been faster, but how can you possibly evaluate whether this is a failure or not without knowing how long it normally takes?

The vast majority of the current size of the Internet, basically 100%, was built after IPv6 was ratified and indeed became a normal part of equipment.

Let's assume that's true... so what? That doesn't tell us anything about how long migrations like this normally take.