Draft Policy ARIN-2011-3: Better IPv6 Allocations for ISPs [Archived]


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Status: NRPM Sections 2.14, 2.15, 2.16, 6.5

Tracking Information

Discussion Tracking

Mailing List:

Formal introduction on PPML on 3 February 2011

Origin - ARIN-prop-121

Draft Policy - 3 February 2011 (with staff assessment)

Last Call - 18 April through 2 May 2011

AC reccomended adoption (as revised) - 24 May 2011

Adopted by the Board - 10 June 2011

Partially implemented - 27 September 2011

Fully implemented - 30 January 2012

Public Policy Mailing List

ARIN Public Policy Meeting:


ARIN Advisory Council:

AC Shepherds:
Robert Seastrom and David Farmer

ARIN Board of Trustees:

10 June 2011


Previous version(s)


30 January 2012

Draft Policy ARIN-2011-3
Better IPv6 Allocations for ISPs

Version/Date: 4 May 2011

Policy Statement:

Amend section 2 as follows:

Replace section 2.10 with the following:

2.10 The term End Site shall mean a single structure or service delivery
address, or, in the case of a multi-tenant structure, a single tenant
within said structure (a single customer location).

Add the following:

2.12 When applied to IPv6 policies, the term serving site shall
mean a location where an ISP terminates
or aggregates customer connections, including, but, not limited to
Points of Presence (POPs), Datacenters, Central or Local switching
office or regional or local combinations thereof.

2.13 When applied to IPv6 policies, the term
“provider assignment unit” shall mean the prefix of the
smallest block a given ISP assigns to end sites (recommended /48).

2.14 The term utilized shall have the following definitions when applied
to IPv6

(i) A provider assignment unit shall be considered fully utilized when
it is assigned to an end-site.

(ii) Larger blocks shall have their utilization defined by dividing the
number of provider assignment units assigned from the
containing block by the total number of provider assignment
units. This ratio will often be expressed as a percentage
(e.g. a/t*100, for a /36 3072/4096 * 100 = 75% utilization)

Replace sections 6.5.1 through 6.5.3 with the following:
6.5.1 Terminology

(a) The terms ISP and LIR are used interchangeably in this document and
any use of either term shall be construed to include both meanings.

(b) The term nibble boundary shall mean a network mask which aligns
on a 4-bit boundary (in slash notation, /n, where n is evenly divisible
by 4, allowing unit quantities of X such that 2^n=X where n is
evenly divisible by 4, such as 16, 256, 4096, etc.)

6.5.2 Initial Allocations to LIRs Size

(a) All allocations shall be made on nibble boundaries.

(b) In no case shall an LIR receive smaller than a /32
unless they specifically request a /36. In no case shall
an ISP receive more than a /16 initial allocation.

(c) The maximum allowable allocation shall be the smallest
nibble-boundary aligned block that can provide an equally
sized nibble-boundary aligned block to each of the
requesters serving sites large enough to satisfy the needs
of the requesters largest single serving site using no more
than 75% of the available addresses.

This calculation can be summarized as /N where
N = P-(X+Y) and P is the organization’s
Provider Allocation Unit X is a multiple of 4 greater
than 4/3*serving sites and Y is a multiple of 4
greater than 4/3*end sites served by largest serving site.

(d) For purposes of the calculation in (c), an end site which
can justify more than a /48 under the end-user assignment
criteria in 6.5.8 shall count as the appropriate number of /48s
that would be assigned under that policy.

(e) For purposes of the calculation in (c), an LIR which has
subordinate LIRs shall make such allocations according
to the same policies and criteria as ARIN. In such a case,
the prefixes necessary for such an allocation should be treated
as fully utilized in determining the block sizing for the parent LIR.
LIRs which do not receive resources directly from ARIN will
not be able to make such allocations to subordinate LIRs and
subordinate LIRs which need more than a /32 shall apply
directly to ARIN.

(f) An LIR is not required to design or deploy their network
according to this structure. It is strictly a mechanism to
determine the largest IP address block to which the LIR
is entitled. Qualifications
An organization qualifies for an allocation under this policy if
they meet any of the following criteria:

(a) Have a previously justified IPv4 ISP allocation from ARIN
or one of its predecessor registries or can qualify for
an IPv4 ISP allocation under current criteria.

(b) Are currently multihomed for IPv6 or will immediately
become multihomed for IPv6 using a valid assigned
global AS number.

In either case, they will be making reassignments
from allocation(s) under this policy to other organizations.

(c) Provide ARIN a reasonable technical justification
indicating why an allocation is necessary. Justification
must include the intended purposes for the allocation and
describe the network infrastructure the allocation will be used to
support. Justification must also include a plan detailing anticipated
assignments to other organizations or customers for one,
two and five year periods, with a minimum of 50 assignments
within 5 years.

6.5.3 Subsequent Allocations to LIRs

(a) Where possible ARIN will make subsequent allocations by
expanding the existing allocation.

(b) An LIR which can show utilization of 75% or more of their
total address space, or more than 90% of any serving site
shall be entitled to a subsequent allocation.

(c) If ARIN can not expand one or more existing allocations,
ARIN shall make a new allocation based on the initial
allocation criteria above. The LIR is encouraged, but not
required to renumber into the new allocation over time
and return any allocations no longer in use.

(d) If an LIR has already reached a /12 or more, ARIN will
allocate a single additional /12 rather than continue
expanding nibble boundaries.

Renumber/move the second paragraph of existing section to

For reference, this would become: Subsequent Allocations for Transition
Subsequent allocations will also be considered for deployments
that cannot be accommodated by, nor were accounted for, under
the initial allocation. Justification for the subsequent subnet size
will be based on the plan and technology provided with a /24
being the maximum allowed for a transition technology.
Justification for transitional allocations will be reviewed every 3
years and reclaimed if they are no longer in use for transitional
purposes. All such allocations for transitional technology will be
made from a block designated for this purpose.

(This paragraph comes from 2010-12 which was adopted after this draft
policy was written).

Replace section 6.5.4 with the following

6.5.4 Assignments to end users shall be governed by the same
practices adopted by the community in section 6.5.8 except
that the requirements in do not apply. An LIR may assign up to a /48 per PoP as well as up to an
additional /48 globally for its own infrastructure.

Add the following to 6.5.7

LIRs which received an allocation under previous policies which is
smaller than what they are entitled to under this policy may receive
a new initial allocation under this policy. If possible, ARIN will
expand their existing allocation.

Delete section 6.9


Here in the Vault, information is published in its final form and then not changed or updated. As a result, some content, specifically links to other pages and other references, may be out-of-date or no longer available.