The IPv6 Adoption Curve

There exist this project that track performance for v6 vs v4. In some countries v6 has above performance to v4, in others places it is worse. You seems to had the bad luck of getting the worse end of the variance.

I don't know what "a couple of years ago" is, but all tier-1 ISPs have IPv6 backbones. There should be no reason for your access ISP to have to tunnel anything to get to a tier-1.

Your statement "Most ISPs (including mine) are using 6rd gateways to get their customers onto the IPv6 backbone" is kind of a red flag. If ISPs aren't connected to a backbone, can you even call them an ISP?

https://xkcd.com/1865/

Even the discontinued Catalyst 6500, which was used (and still is) by a lot of ISPs with the SUP720 supervisor, can do native IPv6.

I think you are completely wrong about this. Routers with native IPv6 were available 15 years ago, and are already getting pulled out to be replaced by the new stuff.

The reality is that, that ISP tier 1s use either Juniper MX or Cisco ASR9000 routers. These routers have good IPv6 performance.

I remember reading about Facebook's migration as a great case study. One example problem they had was that their switches couldn't handle getting a BGP feed with IPv6 addresses when they had not been configured for IPv6.

In other words, when they added IPv6 to their BGP feeds they crashed an entire network segment worth of switches.

This is another massive headache w.r.t IPv6 switchover: all the bugs and edge cases we've found with IPv4 thirty years ago are all brand new wild country problem with IPv6.

Now, we're adopting IPv6 in earnest, but everybody is whining that they want to hang onto NAT.

So, before IPv6 got deployed, everybody shot themselves in the left foot by deploying NAT. And, now that IPv6 is deployed, they continue shooting themselves in the right foot by hanging onto NAT.

There's a fixed pool of IP Addresses that can be allocated. When that allocation pool runs out, no more can be allocated. Allocation occurs in blocks at a very high level and then at subsequent levels more sub block allocation happens.

The INAN ran out of IPs to hand out. That doesn't mean that all of the IPs have been assigned to physical devices attached to the internet. For example the US Government Agencies have tons of IPs they aren't using but that had been previously allocated to them decades ago and can't be taken back.

Also some under-utilized IPv4 address blocks have been recently re-claimed. MIT recently sold off half of its class A to Amazon:

https://www.networkworld.com/article/3191503/internet/mit-se...