ARIN-prop-285: IPv6 Nano-allocations

Date: 18 February 2020

Proposal Originator: Rob Seastrom

Problem Statement:

ARIN’s fee structure provides a graduated system wherein organizations pay based on the amount of number resources they consume.

In the case of the very smallest ISPs, if a 3X-Small ISP (with a /24 or smaller of IPv4) gets the present minimal-sized IPv6 allocation (a /36), its annual fees will double from $250 to $500/year.

According to a Policy Experience Report presented by Registration Services to the AC at its annual workshop in January 2020, this represents a disincentive to IPv6 adoption with a substantial fraction of so-situated ISPs saying “no thanks” and abandoning their request for IPv6 number resources when informed of the impact on their annual fees.

This can be addressed by rewriting subsection 6.5.2(b). Initial Allocation Size to allow allocation of a /40 to only the smallest ISPs upon request, and adding a new clause 6.5.2(g) to cause an automatic upgrade to at least a /36 in the case where the ISP is no longer 3X-Small.

Reserving /40s only for organizations initially expanding into IPv6 from an initial sliver of IPv4 space will help to narrowly address the problem observed by Registration Services while avoiding unintended consequences by accidentally giving a discount for undersized allocations.

Policy Statement:

Replace the current 6.5.2(b) with the following:

b. In no case shall an LIR receive smaller than a /32 unless they specifically request a /36 or /40.

In order to be eligible for a /40, an ISP must meet the following requirements:

  • Hold IPv4 direct allocations totaling a /24 or less (to include zero)
  • Hold IPv4 reassignments/reallocations totaling a /22 or less (to include zero)

In no case shall an ISP receive more than a /16 initial allocation.

Add 6.5.2(g) as follows:

g. An LIR that requests a smaller /36 or /40 allocation is entitled to expand the allocation to any nibble aligned size up to /32 at any time without renumbering or additional justification. /40 allocations shall be automatically upgraded to /36 if at any time said LIR’s IPv4 direct allocations exceed a /24. Expansions up to and including a /32 are not considered subsequent allocations, however any expansions beyond /32 are considered subsequent allocations and must conform to section 6.5.3. Downgrades of any IPv6 allocation to less than a /36 are not permitted regardless of the ISP’s current or former IPv4 number resource holdings.

Timetable for Implementation: Immediate


The intent of this policy proposal is to make IPv6 adoption at the very bottom end expense-neutral for the ISP and revenue-neutral for ARIN. The author looks forward to a future era wherein IPv6 is the dominant technology and IPv4 is well in decline and considered optional leading the Community to conclude that sunsetting this policy is prudent in the interests of avoiding an incentive to request undersized IPv6 allocations.