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On 11 Jan 2011 10:18, Leo Bicknell wrote:<br>
<blockquote cite="mid:20110111161813.GA66815@ussenterprise.ufp.org"
type="cite">
<pre wrap="">If I may oversimplify for a moment, giving more space when 80% utilization is passed, and taking it away the organization drops below 80% utilization can lead to thrashing.</pre>
</blockquote>
<br>
That scenario is exactly why NRPM 12.4.a says "an organization may
remain out of compliance ... as appropriate so as to avoid forcing
returns which will result in near-term additional requests".<br>
<br>
<blockquote cite="mid:20110111161813.GA66815@ussenterprise.ufp.org"
type="cite">
<pre wrap="">Additionally, due to the way IP blocks are allocated and used it's likely that someone dropping below 80% would have to do significant renumbering to return a contiguous block, and that block would then subdivide their original allocation.
</pre>
</blockquote>
<br>
Similarly, that scenario is exactly why NRPM 12.4.b says "Partial
address blocks shall be returned in such a way that the portion
retained will comprise a single aggregate block." Note the word
"retained".<br>
<br>
Let's say you have a /16. Under NRPM 12, you <i>cannot</i> return
a /18, because that would leave you with a /17 and a /18, nor can
ARIN <i>revoke</i> a single /18 because their only authority to do
so is NRPM 12.5, which <i>requires</i> them to follow the same rule
by reference. The registrant could do so voluntarily under another
section that allows otherwise, but ARIN cannot <i>require </i>it.
This was not an accident.<br>
<br>
<blockquote cite="mid:20110111161813.GA66815@ussenterprise.ufp.org"
type="cite">
<pre wrap="">Rather, what is needed is something like you get more when reaching 80% utilization, and ARIN can require the return of space when falling below 40% utilization.
</pre>
</blockquote>
<br>
As John noted, the "low water mark" is currently 50%. That's not
exactly what the policy says, but it seems reasonable enough--and
probably takes a lot less work to enforce.<br>
<br>
<blockquote cite="mid:20110111161813.GA66815@ussenterprise.ufp.org"
type="cite">
<pre wrap="">The second is companies that obtained space prior to utilization requirements. For instance, folks who received space in the classful days. There are plenty of universities for instance that needed more than a Class C, so they got a Class B, even though they only need 25% of it even today. This is going to lead to ARIN contacting folks who have had pretty much no interaction with ARIN during the intervening years, who probably don't have an RSA, and so on.
</pre>
</blockquote>
<br>
That <i>is </i>part of the point, if we can ever agree that NRPM
12 does, in fact, extend to legacy resources. I think it does, but
Owen thinks it doesn't, hence the word "additional" in 12.8, which
makes the text compatible with both views.<br>
<br>
<blockquote cite="mid:20110111161813.GA66815@ussenterprise.ufp.org"
type="cite">
<pre wrap="">Unfortunately, while I like the concept I feel the practical concerns make it of limited value in the IPv4 space. I feel like the level of staff effort is going to be high for minimal gain. Also there is a timing concern, audits take time, renumbering takes time, blocks then sit around to "cool off" before being reissued. Would any IPv4 space get back in the game soon enough to make a meaningful difference?
</pre>
</blockquote>
<br>
There are many other reasons for reclamation; extending the lifetime
of IPv4 is not an important one.<br>
<br>
S<br>
<br>
<pre class="moz-signature" cols="72">--
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking
</pre>
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