[ppml] Policy Proposal 2005-8: Proposal to amend ARIN IPv6 assignment and utilisation requirement - Last Call
The ARIN Advisory Council (AC), acting under the provisions of the ARIN
Internet Resource Policy Evaluation Process (IRPEP), has reviewed policy
proposal 2005-8: Proposal to amend ARIN IPv6 assignment and utilisation
requirement and has determined that there is community consensus in
favor of the proposal to move it to last call. The AC made this
determination at their meeting at the conclusion of the ARIN Public
Policy meeting on April 11, 2006. The results of the AC meeting were
reported by the Chair of the AC at the member meeting. This report can
be found at http://www.arin.net/meetings/minutes/ARIN_XVII/mem.html
The policy proposal text is provided below and is also available at
Comments are encouraged. All comments should be provided to
ppml at arin.net. This last call will expire at 12:00 Noon, Eastern Time,
April 28, 2006.
The ARIN Internet Resource Policy Evaluation Process can be found at
American Registry for Internet Numbers (ARIN)
Policy Proposal 2005-8: Proposal to amend ARIN IPv6 assignment and
This proposal would amend the IPv6 address allocation policies (ARIN's
NRPM, section 6) regarding the definition of the default size of End
Site assignments and the threshold value for End Site allocation
efficiency, no longer assuming the fixed values for End Site assignments
established by RFC3177. Many references to "/48" will need to be
replaced by "End Site assignment".
for example, section 126.96.36.199 should be replaced as follows:
188.8.131.52. Assignment address space size
End Users are assigned an End Site assignment from their LIR or ISP. The
exact size of the assignment is a local decision for the LIR or ISP to
make, using a minimum value of a /64 (when only one subnet is
anticipated for the End Site) up to the normal maximum of /48, except in
cases of extra large end sites where a larger assignment can be justified.
The following guidelines may be useful (but they are only guidelines):
- /64 when it is known that one and only one subnet is needed
- /56 for small sites, those expected to need only a few subnets over
the next 5 years.
- /48 for larger sites
For end sites to whom reverse DNS will be delegated, the LIR/ISP should
consider making an assignment on a nibble (4-bit) boundary to simplify
reverse lookup delegation.
RIRs/NIRs are not concerned about which address size an LIR/ISP actually
assigns. Accordingly, RIRs/NIRs will not request the detailed information on
IPv6 user networks as they did in IPv4, except for the cases described
in Section 6.4.4 and for the purposes of measuring utilization as
defined in this document.
also, section 6.9 will need to be replaced:
6.9. IPv6 Reassignments policy
The size of IPv6 address assignments to End Sites is to be determined by
ISPs and LIRs may choose whether to make changes to their procedures for
assigning address blocks to End Sites. The threshold End Site allocation
efficiency level is between 20% to 50% for most ISPs and LIRs when based
on a 0.94 HD Ratio. ISPs and LIRs will need to operate address plans
according to this target level of End Site allocation efficiency.
there's a need to change ARIN NRPM IPv6 Utilization:
The ARIN NRPM Section 6.7 will be amended so its IPv6 allocation
utilization criteria will reflect the use of a /56 as the unit quantity
in the calculation of the ISP or LIR's end site allocation efficiency.
The current IPv6 Address Allocation and Assignment Policy (section 6 of
ARIN's NRPM) indicates that end sites should be allocated a /48 as a
uniform allocation unit if using more than one host or one subnet.
This proposal alters the existing policy regarding LIR and ISP
assignments to End Sites to allow the unit of assignment to be an LIR or
In assessing the address utilization efficiency for ISPs or LIRs, the
definition of an End Site for the purposes of the calculation of ISP or
LIR End Site allocation efficiency, is to be made according to a /56 size.
This measure, if undertaken generally by all RIRs, in conjunction with
the further measures undertaken by the addressing community regarding
increasing the HD ratio to 0.94, would increase the anticipated useful
lifetime of IPv6 to encompass a period in excess of 100 years, in which
case no further allocation policy changes would be anticipated.
A more detailed rationale is available in Geoff Huston's presentation on
the subject, at RIPE 50, which can be found at: