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Stephen Sprunk stephen at sprunk.org
Thu May 31 17:04:35 UTC 2007

Thus spake "Donald Stahl" <don at calis.blacksun.org>
>> Current policy allows for greater-than-/48 PI assignments if the
>> org can justify it.  However, since we haven't told staff (via
>> policy) what that justification should look like, they are currently
>> approving all requests and several orgs have taken advantage
>> of that.
> I can't imagine what an end-user could come up with to justify
> more than a /48 but what do I know.

First of all, there's disagreement about the definition of "site", and some 
folks hold the opinion that means physical location.  Thus, if you have 100 
sites, those folks would claim you have justified 100 /48s (or one /41). 
Other folks, like me, disagree with that, but there are orgs out there that 
have tens of thousands of locations with a need for multiple subnets per 
location, and that could justify more than a /48 as well via pure subnet 

> And if ARIN's primary goal is to prevent de-aggregation then
> shouldn't there be another fixed allocation size (/40) and block
> to prevent this?

ARIN's goal in v6 is to try to issue blocks so that aggregation is 
_possible_, by reserving a larger block to allow growth, but ARIN can't 
prevent intentional (or accidental) deaggregation, and there's too many 
folks who want to deaggregate for TE purposes to pass a policy officially 
condemning it.

>> So, it's entirely possible someone could get a /40 and
>> deaggregate that into 256 routes if they wanted to.  Given
>> the entire v6 routing table is around 700 routes today, it's
>> obviously not a problem yet :)
> Obviously that's short sighted :) As for the deaggregation-
> anyone deaggregating a /40 into 256 routes should have
> there AS permanently bloackholed :)

I'd agree in principle, but all it takes is a brief look at the CIDR report 
and you'll see that nobody does anything in response to far more flagrant 
examples in v4.  If everyone aggregated properly, we could drop over a third 
of the current v4 table.  This makes me extremely suspicious of ISPs that 
continually whine about routing table bloat whenever loosening policies for 
small orgs is discussed.


Stephen Sprunk      "Those people who think they know everything
CCIE #3723         are a great annoyance to those of us who do."
K5SSS                                             --Isaac Asimov 

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