[arin-ppml] Clarify /29 assignment identification requirement

William Herrin bill at herrin.us
Mon Apr 30 11:51:40 EDT 2012

On 4/28/12, Jimmy Hess <mysidia at gmail.com> wrote:
> Well,  I will say,  that  /32  dedicated user address assignments
> merit more scrutiny.
> Dynamic address pools are different,  because no IP address is
> permanently assigned.


Wave your hands and start the smoke machine before you say that,
'cause it's pure magic.

Once upon a time there was a meaningful difference (from an address
consumption perspective) between a static assignment and a dynamic
pool. Back in the dialup days, a dynamic pool usually meant a many to
one relationship between customers and IP addresses and the "many"
could be as many as 100 customers per address consumed.

Dialup pools still exist but the majority of today's so-called
"dynamic" address pools are DHCP on a LAN or the pool for a cable
modem head end or the pool for a DSLAM. Because theses customers are
in the "always on" category, the relationship between customer and
address falls to worse than 1:1. Because the pool size is not hard
tied to the number of customers which access it, you actually need
extra addresses for system headroom, more total than if you had
explicitly assigned each a /32.

>From a pragmatic address-utilization perspective, the difference
between dynamic and static pools has ceased to exist. Whether the user
hops between addresses or keeps a single address, they indefinitely
hold a /32.

> The question then is not "is this customer actually using the
> resource";  but, are there enough (also identifiable) customers
> served by the pool, with a growth rate to justify a pool of that size.

The question is: do we want to accept ARIN prying in to our customers
who use a single IP address or is that a step too far?

Don't overlook: ARIN must implement their procedures in an even-handed
way. If they make a habit of inquiring into /32 static assignments but
not inquiring in to functionally identical (possibly more consumptive)
dynamic pools, as the address pool tightens they will be sued for the

Bill Herrin

William D. Herrin ................ herrin at dirtside.com  bill at herrin.us
3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
Falls Church, VA 22042-3004

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