Draft Policy 2009-2: Depleted IPv4 reserves

Status: Abandoned

Tracking Information

Discussion Tracking

Mailing List:

Formal introduction on PPML on 23 March 2009

Origin: Policy Proposal 81: Depleted IPv4 reserves

Draft Policy - 23 March 2009 (with staff assessment)

AC Notice to Abandon - 4 May 2009

Public Policy Mailing List

ARIN Public Policy Meeting:

Bridgetown, Barbados

ARIN Advisory Council:

AC Shepherds:
Scott Leibrand and Paul Andersen

18 December 2009
24 January 2009

19 February 2009

19 March 2009

ARIN Board of Trustees:



Draft Policy 2009-2
Depleted IPv4 reserves

Date: 23 March 2009

Policy statement:

(add the following section to the NRPM)

4.1.8 Depleted IPv4 reserves

A limit will be applied to all IPv4 address requests when ARIN's reserve of unallocated IPv4 address space drops below an equivalent /9. When this happens, an ISP or End User may receive up to a single /20 within a six month period. This restriction will be lifted in the event the reserve of unallocated IPv4 address space increases to an equivalent /7.


As the reserve of IPv4 address space becomes smaller, there is a risk that many organizations will be denied resources by a large, last minute request. By implementing a throttle on the last of the IPv4 address space, a more limited group of organizations will be impacted, allowing many organizations to receive ongoing resources during the transition to IPv6.

According to the ARIN statistics page http://www.arin.net/statistics/index.html, 1,993 organizations were issued IP space in 2006 and 2007. Of these allocations 41% of the applicants received less than a /20. On the opposite end, 82 organizations received large blocks. Given that the last reserve of IPv4 space cannot possibly meet the needs of the 82 organizations, the space could be managed in a way to provide for the needs of a wider base of consumers while the largest ISPs build momentum behind IPv6.

The goal is to find a balance between the needs of organizations requiring space, and avoiding the restrictions on end user growth. For this reason, any caps on allocations should be implemented when the reserves are essentially depleted, rather than trying to restrict end user growth when IP space is still readily available.

By putting a six month window on the maximum allocation, the remaining IP space could provide at least one year for everyone to implement other solutions while still being able to obtain an IPv4 address allocation. The time period was also added to provide a consistent rate of depletion, avoiding a scenario where a large organization could queue multiple, justifiable requests, resulting in the scenario the proposal is intended to avoid.

Additional language may need to be added in the event a paid transfer policy is approved. The thinking is to have two pools of available IP. One being the current, IANA allocated, reserve of IP space. The second being IP blocks recovered through monetary incentive. This proposal would apply to the IANA allocated reserves and would not apply to blocks made available by monetary means.

An additional thought was to avoid tying this policy shift specifically to the last /8 allocated by IANA. This allows the policy to come in and out of play in the event that IPv4 address space is abandoned or returned to ARIN.

Timetable for implementation: Immediate