Policy Statement on Address Space Allocations


This method would have (at least) the following advantages (or
disadvantages, from your particular viewpoint):

  1) You could reasonably assure that the number of prefixes in an
     /8 would match what was allocated.

  2) Because of 1, if you get the registries to set their
     allocation policies such that no more than 1024 (or the target number)
     blocks are allocated per /8, you can guarantee that the number of
     routes in an /8 is not too far out of wack with the target.

  3) You can give those people moving providers a grace period to renumber,
     say 30 days. Essentially, the time given to clean up the routing
     tables. This would be a side effect of the "you have 30 days to fix
     the routing tables or else".

  4) You eliminate the wasted space of addresses with prefixes longer than
     /18 being allocated.

The only problem this leaves is how to decide who gets an /18...

That is a *very good question*. Different answers to this question
have *quite different* implications on the address space utilization.


My personal opinion is that you err on the side of giving someone an /18
that doesn't need one, However you DO need to be careful about assigning the
space. The general qualifications I would imagine are:

1) ISP's assigning (non-portable?) address space to non-dialup customers,
on a fairly regular basis.

2) Large-ish companies which of themselves would need the /18.

3) Anyone who is multi-homed on a "permanent" basis. (Probably
mostly covered by 1&2)