The benefits of deploying IPv6 only

NATs do induce a fair amount of latency. It's not exaggerated. Watch Paul Saab from Facebook talk about how much better IPv6 performs at NANOG 64: ▶ this video

Comcast is going for a pure IPv6 core network, they are currently at 60% of their customers getting an IPv6 address of some sort (cable modem or even cable box). T-Mobile's network is IPv6 as well. Especially for customer devices that support 464XLAT: link There is a LOT of support for IPv6, and many companies like Facebook are finding that IPv6 actually offers better performance end to end for their users. Take a look at this NANOG presentation: ▶ this video

Exactly. And as the home speeds reach 1Gbps to the home, there will not be enough CGN boxes that will be able to sustain that load, so one of the two options: 1) more stateless mechanisms will be used (lw4o6, MAP) - which do not give the entire IPv4 address to residential users => so even if the service has an IPv4 address, the clients might have to go through the hurdles to get to it. Service providers are planning to go IPv6-only, and content providers already note that IPv6 gives a double-digit performance increase compared to IPv4 [1] 2) The residential ISPs will debundle the IPv4 from the cost - given that a lot of the sites average consumer needs (google, facebook, youtube, netflix) are already IPv6-enabled. For this case, you will not be even able to see that something is "wrong". Just the users will click on the link, see it's not reachable, say "huh?" and move on. [1] ▶ this video - 1h12 well spent.

This is contrarian to real world testing: link ▶ this video Facebook and many other companies are finding that IPv6 is faster, personally at home I have found that disabling IPv4 allows me to more quickly buffer and stream Netflix, and about 30 - 40% of my traffic is IPv6. My Apple TV is the last hold-out that still seems to use IPv4 over IPv6 for Netflix.

That's simply not true. Over 22% of US Internet consumers have IPv6 addresses. Your mobile phone probably has a (few) IPv6 addresses. From NANOG 64: ▶ this video

In addition to other answers, here is some food for thought: Some operators are already working on turning IPv4 off in their networks: ▶ this video

An engineer at Comcast in this nanog video [1] claims they have 60% penetration in their own network for IPv6. Which is excellent news. [1]: ▶ this video

There will be no abrupt end. Just the price per IP will slowly grow, and the usefulness of this IP will slowly fade. There's no panic. The trick with IPv6 deployment is predicting two years in advance the moment will you need IPv6 "tomorrow" - because for a lot of orgs that's how long it takes. I'll repost a link from the recent NANOG meeting here about the folks seriously discussing their plans of going IPv6-only: ▶ this video By the way, if you're reading this from a smartphone in the US, try this link: link I thoroughly enjoyed the moment when one networking pro (who dealt with IPv6 20 years ago and not since) was telling me he won't have IPv6 till he retires, realized he had his on his LTE connection and was using it for quite some time already! :-) I repeat myself from another post: One out of five users hitting google.com and facebook.com in the US today does so over IPv6.