[arin-ppml] IPv4 Fragment Managemnt policy proposal

[michael.dillon at bt.com]

> Each time ARIN approves an IPv4 request which it cannot 
> satisfy from 4 or fewer bit-aligned blocks of free address 
> space, ARIN shall notify the requestor that there is 
> insufficient free address space to meet their request and 
> shall offer the requestor their choice of the following
> alternatives:
> 
> 
> a. They can have the largest 4 available bit-aligned blocks 
> of free addresses.
> 
> 
> b. This section reserved -- (in case we implement the waiting 
> list for unmet requests policy)
> 
> 
> c. They can seek resources through the directed transfer 
> policy in section 8.3 of the NRPM.

Seems like a good idea. 

One thing to be aware of is that ARIN does not allocate CIDR
blocks. They allocate IP address ranges, i.e. from a start
address to an ending address. One time we received an allocation
that consisted of two disjoint ranges. One of those was 3/4
of a reserved block where we had already received 1/4 of the
block previously. And the other was 1/4 of a new reserved block.

It might be a good idea to think this through and see whether
or not it can be simplified to say that ARIN will never allocate
more than 4 blocks to satisfy a request, and leave off the bit
about when there is insufficient free space.

--Michael Dillon