Redundant AS's

Henk Uijterwaal henk at
Wed Mar 18 02:18:59 CDT 2009

tvest at wrote:
> On Mar 17, 2009, at 11:47 AM, Simon Brilus wrote:
>> Out of interest, is there a report that details the number of unused 
>> older AS's in the Internet and what is being done to recover them to 
>> recycle, as we approach the 53k mark and the 32 bit numbering scheme, 
>> it strikes me that we probably have a lot of stagnant AS's out there 
>> due to takeovers etc..
>> Any thoughts?
>> Simon
> It's a bit dated now, but the RIPE report, ASN MIA, sounds like what 
> you're looking for...

When I look at this more recently, the conclusion still seems to be
valid: we'll run out of 16 bit ASN's somewhere in 2011 to 2013.  There
are a lot of unused ASN's out there.  Recovering them will postpone the
problem by a few years but it won't solve it.  The basic problem with
recovery is how to decide if an ASN is really no longer used/needed.
There is (still) no mechanism to do this.


Henk Uijterwaal                           Email: henk.uijterwaal(at)
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