[arin-ppml] Policy Proposal 113: IPv6 for 6rd

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Tue May 4 15:15:05 EDT 2010

ARIN received the following policy proposal and is posting it to the
Public Policy Mailing List (PPML) in accordance with Policy Development

This proposal is in the first stage of the Policy Development Process.
ARIN staff will perform the Clarity and Understanding step. Staff does
not evaluate the proposal at this time, their goal is to make sure that
they understand the proposal and believe the community will as well.
Staff will report their results to the ARIN Advisory Council (AC) within
10 days.

The AC will review the proposal at their next regularly scheduled
meeting (if the period before the next regularly scheduled meeting is
less than 10 days, then the period may be extended to the subsequent
regularly scheduled meeting). The AC will decide how to utilize the
proposal and announce the decision to the PPML.

In the meantime, the AC invites everyone to comment on the proposal on
the PPML, particularly their support or non-support and the reasoning
behind their opinion. Such participation contributes to a thorough
vetting and provides important guidance to the AC in their deliberations.

Draft Policies and Proposals under discussion can be found at:

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Policy Proposal 113: IPv6 for 6rd

Proposal Originator: Alain Durand, Marla Azinger, Mark Townsley

Proposal Version: 1

Date: 4 May 2010

Proposal type: New

Policy term: permanent

Policy statement:

If you have non contiguous IPv4 addresses then you automatically qualify
for IPv6 space for 6rd.  Upon receipt of a 6rd request, the minimum
subnet required for the functionality of 6rd will be automaticlly
granted and larger blocks will be granted based on justification.  If
IPv6 addresses are already allocated to the requestor then an effort
will be made to give them an IPv6 allocation that is preferably
contiguous to the prior existing one.  The use of this address space
will be used for 6rd and returned to ARIN when 6rd is no longer used on
the network. Justification for use of IPv6 for 6rd will be reviewed
every 3 years and reclaimed if it is not in use. Requestor will be
exempt from returning all or a portion of the address space when 6rd is
no longer used if they can show justification for need of the 6rd
address space for other existing IPv6 addressing requirements.

The 6rd prefix is an RIR delegated IPv6 prefix.  It must encapsulate an
IPv4 address and must be short enough so that a /56 or /60 can be given
to subscribers. This example shows how the 6rd prefix is created based
on a /32 IPv6 prefix using RFC1918 address space from

        SP IPv6 prefix: 2001:0DB8::/32
        v4suffix-length: 24 (from 10/8, first octet (10) is excluded
                             from the encoding)
        6rd CE router IPv4 address:
        6rd site IPv6 prefix: 2001:0DB8:6464:0100::/56

This example shows how the 6rd prefix is created based on a /28 IPv6
prefix using one of several non-contiguous global address ranges:

         SP IPv6 prefix: 2001:0DB0::/28
         v4suffix-length: 32 (unable to exclude common bits
                              due to non-contiguous IPv4 allocations)
         6rd CE router IPv4 address:
         6rd site IPv6 prefix: 2001:0DBC:0000:2010::/60


6rd is intended to be an incremental method for deploying IPv6 and
bridge the gap for End Users to the IPv6 Internet.  The method provides
a native dual-stack service to a subscriber site by leveraging existing
infrastructure. If an entity already has a /32 of IPv6 they can not use
the same /32 for native IPv6 as they do for the 6rd routing and a
separate minimum size of a /32 is required while a larger subnet like a
/28 may be needed based on a non-contiguous IPv4 addressing plan.

Timetable for implementation: Immediate

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