[arin-ppml] Draft Policy ARIN-2010-8: Rework of IPv6 assignment criteria - adopted
On 11 January 2011 the ARIN Board of Trustees adopted the following policy:
Draft Policy ARIN-2010-8: Rework of IPv6 assignment criteria
This policy will be be implemented no later than 30 April 2011.
Board of Trustees Meeting Minutes are available at:
Draft Policy and Policy Proposal texts are available at:
The ARIN Policy Development Process can be found at:
Communications and Member Services
American Registry for Internet Numbers (ARIN)
## * ##
Draft Policy ARIN-2010-8
Rework of IPv6 assignment criteria
Version/Date: 23 November 2010
Replace section 6.5.8 as follows;
6.5.8. Direct assignments from ARIN to end-user organizations
126.96.36.199 Initial Assignment Criteria
Organizations may justify an initial assignment for addressing devices
directly attached to their own network infrastructure, with an intent
for the addresses to begin operational use within 12 months, by meeting
one of the following criteria:
a. Having a previously justified IPv4 end-user assignment from ARIN or
one of its predecessor registries, or;
b. Currently being IPv6 Multihomed or immediately becoming IPv6
Multihomed and using an assigned valid global AS number, or;
c. By having a network that makes active use of a minimum of 2000 IPv6
addresses within 12 months, or;
d. By having a network that makes active use of a minimum of 200 /64
subnets within 12 months, or;
e. By providing a reasonable technical justification indicating why IPv6
addresses from an ISP or other LIR are unsuitable.
Examples of justifications for why addresses from an ISP or other LIR
may be unsuitable include, but are not limited to:
• An organization that operates infrastructure critical to life safety
or the functioning of society can justify the need for an assignment
based on the fact that renumbering would have a broader than expected
impact than simply the number of hosts directly involved. These would
include: hospitals, fire fighting, police, emergency response, power or
energy distribution, water or waste treatment, traffic management and
• Regardless of the number of hosts directly involved, an organization
can justify the need for an assignment if renumbering would affect 2000
or more individuals either internal or external to the organization.
• An organization with a network not connected to the Internet can
justify the need for an assignment by documenting a need for guaranteed
uniqueness, beyond the statistical uniqueness provided by ULA (see RFC
• An organization with a network not connected to the Internet, such as
a VPN overlay network, can justify the need for an assignment if they
require authoritative delegation of reverse DNS.
188.8.131.52 Initial assignment size
Organizations that meet at least one of the initial assignment criteria
above are eligible to receive an initial assignment of /48. Requests for
larger initial assignments, reasonably justified with supporting
documentation, will be evaluated based on the number of sites in an
organization’s network and the number of subnets needed to support any
extra-large sites defined below.
The initial assignment size will be determined by the number of sites
justified below. An organization qualifies for an assignment on the next
larger nibble boundary when their sites exceed 75% of the /48s available
in a prefix. For example:
More than 1 but less than or equal to 12 sites justified, receives a /44
More than 12 but less than or equal to 192 sites justified, receives a
More than 192 but less than or equal to 3,072 sites justified, receives
a /36 assignment;
More than 3,072 but less than or equal to 49,152 sites justified,
receives a /32 assignment;
184.108.40.206.1 Standard sites
A site is a discrete location that is part of an organization’s network.
A campus with multiple buildings may be considered as one or multiple
sites, based on the implementation of its network infrastructure. For a
campus to be considered as multiple sites, reasonable technical
documentation must be submitted describing how the network
infrastructure is implemented in a manner equivalent to multiple sites.
An organization may request up to a /48 for each site in its network,
and any sites that will be operational within 12 months.
220.127.116.11.2 Extra-large sites
In rare cases, an organization may request more than a /48 for an
extra-large site which requires more than 16,384 /64 subnets. In such a
case, a detailed subnet plan must be submitted for each extra-large site
in an organization’s network. An extra-large site qualifies for the next
larger prefix when the total subnet utilization exceeds 25%. Each
extra-large site will be counted as an equivalent number of /48 standard
18.104.22.168 Subsequent assignments
Requests for subsequent assignments with supporting documentation will
be evaluated based on the same criteria as an initial assignment under
22.214.171.124 with the following modifications:
a. A subsequent assignment is justified when the total utilization based
on the number of sites justified exceeds 75% across all of an
organization’s assignments. If the organization received an assignment
per section 6.11 IPv6 Multiple Discrete Networks, such assignments will
be evaluated as if they were to a separate organization.
b. When possible subsequent assignments will result it the expansion of
an existing assignment by one or more nibble boundaries as justified.
c. If it is not possible to expand an existing assignment, or to expand
it adequately to meet the justified need, then a separate new assignment
will be made of the size justified.
126.96.36.199 Consolidation and return of separate assignments
Organizations with multiple separate assignments should consolidate into
a single aggregate, if feasible. If an organization stops using one or
more of its separate assignments, any unused assignments must be
returned to ARIN.
This proposal provides a complete rework of the IPv6 end-user assignment
criteria, removing the dependency on IPv4 policy, providing clear
guidance in requesting larger initial assignments, and eliminating
HD-Ratio as criteria for evaluating end-user assignments.
The HD-Ratio is replaced with a simplified 75% utilization threshold
based on nibble boundaries for end-user assignments. This threshold is
somewhat more restrictive for larger assignments, while slightly less
restrictive for the smaller /44 assignments, than the HD-Ratio. However,
in both cases it is much easier for an end-user to understand the policy
criteria that applies to them.
The following general concepts are included:
• Previously justified IPv4 resources may be used to justify the need
for IPv6 resources
• Internet multihoming is sufficient justification for an IPv6 end-user
assignment in and of itself
• Networks with more than 2000 hosts have a justified need for IPv6
resources; as is the case in current policy, it is just more clearly
stated without relying on a reference to, and the consequences of, IPv4
• Networks with more than 200 subnets have a justified need for IPv6
resources, independent of the number of hosts they have
• Other end-users, not meeting one of the previous criteria, must
justify why an ISP or LIR assignment is not sufficient for their needs
• Reservations are no longer necessary as ARIN has committed to sparse
assignment for IPv6
• Providing sufficiently large initial assignments based on nibble
boundaries along with sparse assignments will reduce route table growth
caused solely by subsequent assignments
Organizations with multiple sites may receive a /48 for each site in
their network. A campus with multiple buildings may be considered as one
or multiple sites, based on the implementation of its network
infrastructure. When multiple separate organizations have networks in
the same building, such as in the case of a multi-tenant building, each
organization justifies a separate /48 for its network at the site.
The 25% subnet utilization for an extra-large site is proposed as the
threshold for a larger prefix in order to allow an extra-large site
enough room to create an organized subnet plan. Requiring denser usage
would make it almost impossible for an extra-large site to maintain any
kind of organized subnet plan. Furthermore, even at 25% utilization,
more than 16,384 subnets are required to justify more than a /48 for a
site. Few, if any, sites can actually meet or exceed this threshold.
Organizations may have multiple separate assignments due to previous
subsequent assignments made per clause 188.8.131.52.c or through Mergers and
Acquisitions in section 8.2. These multiple separate assignments must be
considered in total when making subsequent assignments, unless they are
part multiple discrete networks, per section 6.11.
The ARIN Board of Trusties should consider incentives that provide
additional motivation for end-users to consolidate into a single
aggregate per section 184.108.40.206 of this policy.
Timetable for implementation: Immediate