IP renumbering timeframe

In the referenced message, Ralph Doncaster said:

> > What is the generally accpted timeframe for renumbering? My reading of
> > ARIN policy would seem to imply at least 30 days.
> The bottom line is the space is theirs and they can do whatever they want
> with it.

Is that true? I thought the space belongs to ARIN, and they loan it to
certain parties. Those parties can use the IPs in accordance with ARIN



but yes, registries allocate based upon rules (most ISPs are registries).
In theory, IANA could revoke, forcing the RiR's to revoke the
space, forcing the LiR's to revoke the space, and so on until Joe Blow's
/29 gets revoked.

In practice, this has not to my knowledge ever occured. If we ever do
reach a point where exhaustion of IPv4 is imminent, I would expect this
to occur. Presently, there is a voluntary request for unused address
space, but as long as it is voluntary, I don't expect there being
any meaningful return of unused space.