it is not trival to renumber a network that is managable.
this is the key point, e.g. why autoconf is useless in the real ops world. until interfaces have long-lived identities other than their ip addresses, real networks will bind to real ip addresses which must propagate far enough to get to very remote management stations and aggregators. systems where dynamic assignment is pushed from a database, e.g. dhcp, which can be accessed from the management system are just starting to being used. the rest of the real managed world is still static. those are the only two games in the managed town, of which i am aware. the rest of the brilliant ideas are managable-ops-clue-free fantasies, propaganda, or both. e.g. auto-conf is a non-starter except on a small home network. link local is a non-starter. ... randy