[arin-ppml] Draft Policy 2010-2: /24 End User Minimum Assignment Unit - Last Call

Member Services info at arin.net
Wed Apr 28 11:03:14 EDT 2010

The ARIN Advisory Council (AC) met on 21 April 2010 and decided to
send the following draft policy to last call:

    Draft Policy 2010-2: /24 End User Minimum Assignment Unit

The AC met in accordance with the ARIN Policy Development Process which
requires the AC to meet within 30 days of the conclusion of the Public
Policy Meeting to make decisions about the draft policies that had been

Feedback is encouraged during this last call period. All comments should
be provided to the Public Policy Mailing List. This last call will
expire on 12 May 2010. After last call the AC will conduct their
last call review.

The draft policy text is below and available at:

The ARIN Policy Development Process is available at:


Member Services
American Registry for Internet Numbers (ARIN)

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Draft Policy 2010-2
/24 End User Minimum Assignment Unit

Version/Date: 2 March 2010

Policy statement:

Replace section of the NRPM with the following: Multihomed Connection

For multi-homed end-users who demonstrate an intent to announce the
requested space in a multihomed fashion to two or more distinct ASNs not
owned or controlled by the end-user, the minimum block of IP address
space assigned is a /24. If assignments smaller than a /24 are needed,
multihomed end-users should contact their upstream providers. When
prefixes are assigned which are longer than /20, they will be from a
block reserved for that purpose so long as that is feasible.

Renumber the existing paragraph under the 4.3.6 to Utilization requirements for additional Assignment

Add the following paragraph Additional assignments for small multi-homers

Any end-user that possesses an assignment smaller than /22 under any
part of section 4.3 shall not be able to get an additional assignment
unless they agree to return all existing 4.3 assignments with a /23 or
longer prefix within 12 months of receiving a new assignment. The new
assignment shall be sized to accommodate their existing utilization in
addition to their justified additional growth space under section The common cases for this are expected to be a /24 returned
after receipt of a /23, or a /23 returned after receipt of a /22.


This policy attempts to incorporate the recent and historical
discussions of policy for multi-home users on PPML. The intent is to
provide as fair a process as possible for multi-homed organizations down
to the smallest feasible size while still preserving some control over
growth in the routing table.

It has been repeatedly noted that /24 multi-homers exist today with PA
space and still occupy a routing table slot, so, it is unlikely that
moving this boundary to /24 would significantly impact the routing table.

By requiring smaller assignments to renumber and return, rather than add
more small blocks to their assignments, this policy seeks to further
reduce the chances of unnecessary growth in the routing table and
encourage good aggregation where possible.

Does this apply only to end users? Yes, this policy applies only to end
users. This policy does not represent a good solution for organizations
that are delegating space to other entities. If a case can be made that
such a policy is needed for ISPs, then, the author is happy to work with
interested parties to craft such a policy, but, this policy would be
unnecessarily onerous on ISPs, and, as an ISP policy could be somewhat
onerous to their peers and/or upstream providers.

What about resources obtained from policies other than 4.3 or outside of
ARIN? Such resources would not be counted for excluding an organization
from this policy. The intent is to limit IPv4 micro-allocations for
multi-homed end-user organizations under this policy to a single
assignment unless each such assignment is /22 or larger. This is to
prevent unnecessary routing table growth. This is a tradeoff, and, not
the ideal solution for smaller end-user organizations, however, author
believes that this is the best policy likely to gain consensus at this
time and believes that it is incrementally far better for such
organizations than current policy.

If I grow, I have to renumber? Not necessarily... If you have a /24
under this policy, and you want to grow that, then, you will likely need
to renumber. Depending on ARIN resource management and timing, ARIN may
simply be able to give you the /23 that includes your /24. More likely,
you will get a new /23, have 1 year to renumber into that and return
your /24. At most, you would be subject to two such renumbering cycles
under this policy (24->23 and 23->22) before you meet the criteria for
other policies which do not require renumbering.

Other policies don't include renumbering provisions, why this one? The
policy which allows multi-homed organizations to get a /22 was
originally written at /24. That policy was shouted down and /22 was the
compromise achieved to gain community consensus for anything smaller
than /20. Author hopes that this compromise will allow many
organizations to get resources they need with minimal impact while
assuring the community that doing so will not cause an explosion in the
routing table.

Timetable for implementation: Immediate

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