His idea, if I understand it right, is to do two transitions instead of one:
1) first, add 12 bytes to each address
2) then build out the IPv6 on this free space.
The problem is that (1) can not happen everywhere at once. So your “128bit IPv4” stack still needs a way to talk to “32 bit IPv4” stack, so you need to maintain somewhere a flag which one do you use.
So the problem is exactly the same as with the transition - you need dual stack everywhere, and a means to select which one to use.
I think the simplest analogy of this that makes the complexities more obvious to understand:
Imagine you have a network based on copper. (Twisted pair). Please upgrade the entire network to the optical fiber while maintaining the transparent connectivity between all the hosts at all times.
Edit to add:
bad analogy. Copper or fiber are sufficiently non-leaky to make the task relatively simple. Maybe a better one could be to migrate the hosts from IP to IPX. (Which is kinda similar to IPv6 sufficiently that it renders the analogy moot :)
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His idea, if I understand it right, is to do two transitions instead of one: 1) first, add 12 bytes to each address 2) then build out the IPv6 on this free space.
The problem is that (1) can not happen everywhere at once. So your “128bit IPv4” stack still needs a way to talk to “32 bit IPv4” stack, so you need to maintain somewhere a flag which one do you use.
So the problem is exactly the same as with the transition - you need dual stack everywhere, and a means to select which one to use.
I think the simplest analogy of this that makes the complexities more obvious to understand:
Imagine you have a network based on copper. (Twisted pair). Please upgrade the entire network to the optical fiber while maintaining the transparent connectivity between all the hosts at all times.
Edit to add:
bad analogy. Copper or fiber are sufficiently non-leaky to make the task relatively simple. Maybe a better one could be to migrate the hosts from IP to IPX. (Which is kinda similar to IPv6 sufficiently that it renders the analogy moot :)