[arin-ppml] Clarify /29 assignment identification requirement

Jimmy Hess mysidia at gmail.com
Mon Apr 30 19:16:33 EDT 2012

On 4/30/12, William Herrin <bill at herrin.us> wrote:
> 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.

No.    The customer holds a /32  as long as they have a valid DHCP
lease assigned to their connected equipment.     DHCP leases have
finite durations,  and will expire soon after the customer
disconnects;  therefore,  these are not indefinitely assigned.

Only the overall pool is indefinitely assigned,  renumbering or
resizing the pool is simple, since addresses are already dynamic,
therefore  capacity management of the pool becomes simple and easily
manageable using simple monitoring tools.

Each and every DHCP assignment will definitively  cease to exist as
soon as the customer cancels service.  Which makes assignments
inherently definite in duration,  and is one of the benefits of
implementing DHCP pools for customer management, and minimal numbers
of static assignments ---  administrative overhead of IP address
management is reduced.

When ISPs manage /32 allocations manually, instead of utilizing a DHCP
pool,  even when the allocations are properly documented,  periodic
manual efforts,  with a level of expense similar to address
renumbering, is required to  "clean up"  and  relinquish  old  no
longer used allocations.

In addition when old  cancelled customers   with  /32  assignments
do not happen to be contiguous IP addresses,  it is tempting to a
service provider to fail to  renumber and consolidate existing /32
assignments,     even when there are sufficient numbers of unused (but
fragmented) IP addresses  to satisfy the need for their next  3 months
 of   /28  allocations.

> 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?

ARIN has a duty to take reasonable steps to validate justifications
for address assignment.

ARIN is not "prying",  because information requests are not merely to
satisfy some idle curiosity of ARIN's,   they are actually required to
reasonably distinguish between
improper applications and valid justifications.

> 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
> favoritism.

ARIN is not necessarily required to provide equal scrutiny to all
systems that different
ISPs use for providing IP addresses to end users.

Especially when certain methods may more commonly provide greater efficiency
and scalability.

DHCP pools require  spare capacity to accomadate growth.

/29 and /32 assignments require spare capacity to make new assignments,
and in addition  larger amounts of  IP address space becomes wasted
and unusable due to IP address assignment space fragmentation.

And  potential lax cleanup policies of many providers.
Suggest direct assignments should receive specific scrutiny.

(Not that justification for dynamic pool sizes should not be subject
to verification)


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