> What makes you think that companies would have been willing to make the effort to deploy "IPv4+" any more than IPv6? The hallmark of a good IPv4+ solution is

> What makes you think that companies would have been willing to make the effort to deploy "IPv4+" any more than IPv6? The hallmark of a good IPv4+ solution is that it autodeploys without anyone at the network configuration and administration level having to think too much about it. IPv6+IPv4 by contrast generally doubles the configuration complexity of more things than you can count. It is true that for IPv4+ to be successful nearly everyone currently using IPv4 would need some sort of behind the scenes upgrade to be IPv4+ compatible first before the extended address space would be portable. And that includes incremental upgrades of just about everything that touches IPv4 or IPv4 compatible addresses.