Comment by Dagonfly

> Same addr and routes as before

But same addr is the problem we are trying to solve in the first place. Using your IP-new proposal (let's call it IPv5): If every IPv5 addr is just a padded version of the same IPv4 addr, then once IPv4 addresses are exhausted the IPv4-mapped-into-IPv5 addresses are also exhausted.

At that point you need to start handing out IPv5 addresses to hosts without an IPv4 address. And then, how does a IPv5-only host talk to a IPv4-only legacy host? That's the fundamental issue!

The same addr thing only buys you time until the address exhaustion becomes real.