[arin-ppml] Taking back UNUSED addresses.

Stephen Sprunk stephen at sprunk.org
Tue Sep 16 16:19:15 EDT 2008

Leo Bicknell wrote:
> In a message written on Mon, Sep 15, 2008 at 07:26:54AM +1000, Geoff Huston wrote:
>> The current value is 0.4322 (unadvertised addresses are 43.22% of the  
>> advertised address) Which means that of the total allocated address pool, 30.17% of the addresses are not _currently_ advertised into my particular view of the global routing table.
> I wonder if any of the parties could easily re-generate the numbers for two groups of addresses, those allocated prior to December 1997 (ARIN's founding date), and those after.

The only official stats I've seen that break out legacy assignments are at:

According to that preso, 56% of legacy assignments that don't show up, 
even partially, in the DFZ.  Also, 52% of the network records and 48% of 
org records haven't been updated since 1997 and I'll wager there is a 
very high correlation between the sets.  Some is in private use, sure, 
but a lot of that space that has been abandoned and could be reclaimed 
with no complaints, if there were policy allowing ARIN to do so.

Unfortunately, those statistics do not account for the varying size of 
legacy blocks; they just count records, which could be anywhere from /8 
to /24.  It is "common knowledge" that the problem is worst at the 
smaller end of the spectrum, but I personally know of more Class B (er, 
/16) blocks than Class C (er, /24) ones that aren't in use, so I wonder 
how correct that assumption is.

Not that any of this is going to make any significant difference to the 
exhaustion date, but IMHO it does make ARIN less of a target for 
complaints (legal or moral) if we've cleaned up the most obvious waste 
of space before we have to start denying qualified new applicants.


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