[ppml] Proposed Policy: IPv6 HD ratio

Member Services memsvcs at arin.net
Mon May 9 12:27:35 EDT 2005

ARIN received the following proposed policy.  In accordance with the
ARIN Internet Resource Policy Evaluation Process, the proposal is being
posted to the ARIN Public Policy Mailing List and being placed on ARIN's

The ARIN Advisory Council will review the proposal and within ten
working days may decide to:
1)  support the proposal as is,
2)  work with the author to clarify, divide or combine one or more
policy proposals, or
3)  not support the policy proposal.

If the AC supports the proposal or reaches an agreement to work with the
author, then the proposal will be posted as a formal policy proposal to
the Public Policy Mailing List and it will be presented at the Public
Policy Meeting.  If the AC does not support the proposal, then the
author may elect to use the petition process to advance the proposal. If
the author elects not to petition or the petition fails, then the
proposed policy will be considered closed.

The ARIN Internet Resource Policy Evaluation Process can be found at:

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Member Services
American Registry for Internet Numbers (ARIN)

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Policy Proposal Name: IPv6 HD ratio

Author: Andrew Dul

Policy term: permanent

Policy statement: Change HD ratio used for IPv6 allocations to 0.94

This would modify sections & 6.7 (including the HD-ratio to
percentage table) of the NRPM.

Rationale: Recent research has shown that based upon certain growth
models the current IPv6 allocation policy using the HD ratio of 0.8 will
allocate between a
/1 and /4 of Ipv6 address space over the period of about 60 years.


By changing the HD ratio to 0.94, this would require LIRs to have a
higher utilization of the /48s that are assigned to end sites before
being able to obtain additional allocations.  This policy would change
the threshold for an LIR holding a /32 from approximately 11% to 51%.
An LIR with a /20 would have a utilized percentage of approximately 31%
vs. the current 2%.

This policy may also prevent the hoarding of IPv6 addresses by current
organizations with large customer bases, but no substantial current IPv6

Timetable for implementation: Within 30 days of ratification by the BoT.

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