> The major reason why we aren't seeing adoption is that > there is no commercial need - that's the real driver. Not entirely true. All big networks using pri

> The major reason why we aren't seeing adoption is that > there is no commercial need - that's the real driver. Not entirely true. All big networks using private IP addresses and NAT (recent ISPs, and most cellular networks for example) have to implement carrier grade NAT (CGN), and it's getting painful and costly. Also, a lot of web applications require low latency. The way to do this is often to create a lot of parallel connections to fetch content. For example, a google map can easily span 40+ TCP connection to fetch all the tiles making the MAP. During peak time this can put a very high load on CGN gateways. And when they overload, some sessions lags or time out (missing or delayed tiles => bad user experience). This is why all big players on the web now support IPv6 and use it when possible. IPv6 avoid CGN and does not have such issues. Even if that still makes a small percentage of all traffic, it's steadily rising now. IPv6 is finally happening, because the alternative (CGN) is too painful to scale. Now old large ISP with little growth don't care: they have plenty of public IPv4 addresses, with enough in stock to absorb their limited growth for a while. So they don't need CGN and don't care about IPv6. I don't expect this to change. But with mobile and cellular getting a bigger and bigger share and mostly on NAT with IPv4 there is enough of a pressure to move to IPv6 to make sure it'll be mainstream by the end of the decade.