| ISPs should be | advising their customers to be prepared for renumbering since it is in the | customer's best interests. One of the ironies in many of these discussions is that ISPs are very keen on not having to renumber their customers if they themselves have to switch providers, therefore they should get sizable address allocations that are liklier to be portable. Yet, any customer of theirs is then instantly in the same position: if an end user wants to switch ISPs, unless it has portable address space, the end user has to renumber. Few tears are cried here over that (modulo Eliot Lear). That said, I see no reason to be fair and even-handed just for the sake of seeming to be "nice". Otherwise, we degenerate into Bill Manning's "constant renumbering" Internet [*], running out of addresses through allocation of too-large blocks, or reversing CIDR and putting an end to hierarchical routing [**]. Therefore, a minimum allocation unit, which has a "price", either in terms of actual dollars paid to a RIPE-like registry or in terms of a set of requirements set out by such a registry (or both), where the price is unattractive to end users is a reasonable solution. Sean. P.S.: [*] one fun and useful thing to think about is what would break if every device in the Internet (routers and hosts) were to be shut down and brought back up, with or without new addresses. [**] hierarchical routing is the only known means of maintaining adequate routing in an enormous growing network.