ARIN-PPML Message

[ppml] Policy Proposal 2005-9: 4-Byte AS Number - Last Call

The ARIN Advisory Council (AC), acting under the provisions of the ARIN 
Internet Resource Policy Evaluation Process (IRPEP), has reviewed policy 
proposal 2005-9:  4-Byte AS Number and has determined that there is 
community consensus in favor of the proposal, as edited below, to move 
it to last call. The AC removed the nomenclature and edited the 
terminology. 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 
http://www.arin.net/policy/proposals/2005_9.html

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 
http://www.arin.net/policy/irpep.html

Regards,

Member Services
American Registry for Internet Numbers (ARIN)

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Policy Proposal 2005-9: 4-Byte AS Number

Policy statement:

This policy proposal nominates 3 dates for changes to the current AS 
Number allocation policy for the registry:

- Commencing 1 January 2007 the registry will process applications that 
specifically request 32-bit only AS Numbers and allocate such AS numbers 
as requested by the applicant. In the absence of any specific request 
for a 32-bit only AS Number, a 16-bit only AS Number will be allocated 
by the registry.

- Commencing 1 January 2009 the registry will process applications that 
specifically request 16-bit only AS Numbers and allocate such AS Numbers 
as requested by the applicant. In the absence of any specific request 
for a 16-bit only AS Number, a 32-bit only AS Number will be allocated 
by the registry.

- Commencing 1 January 2010 the registry will cease to make any 
distinction between 16-bit only AS Numbers and 32-bit only AS Numbers, 
and will operate AS number allocations from an undifferentiated 32-bit 
AS Number allocation pool.

Terminology

"16-bit only AS Numbers" refers to AS numbers in the range 0 - 65535

"32-bit only AS Numbers" refers to AS Numbers in the range 65,536 - 
4,294,967,295

"32-bit AS Numbers" refers to AS Numbers in the range 0 - 4,294,967,295

Policy Rationale

Recent studies of AS number consumption rates indicate that the existing 
16-bit pool of unallocated AS Numbers will be exhausted sometime in the 
period between 2010 and 2016, absent of any concerted efforts of 
recovery of already-allocated AS Numbers [1] [2]. Standardization work 
in the IETF has produced a document that is currently being submitted as 
a Proposed Standard that will expand the AS Number space to a 32-bit 
field [3].

It is noted that some advance period may be required by network 
operators to undertake the appropriate procedures relating to support of 
32-bit AS numbers, and while no flag day is required in the transition 
to the longer AS Number field, it is recognised that a prudent course of 
action is to allow for allocation of these extended AS numbers well in 
advance of an anticipated 16-bit AS Number exhaustion date.

This policy proposal details a set of actions and associated dates for 
RIR AS Number allocation policies to assist in an orderly transition to 
use of the 32-bit AS Number space.

The essential attributes of this policy proposal are to facilitate the 
ease of transitional arrangements by equipment vendors, network managers 
and network operations staff, to provide the industry with some 
predictability in terms of dates and associated actions with respect to 
registry operational procedures for AS Number allocations.

References

[1] Daily AS Number Report, http://www.potaroo.net/tools/asns [2] ASNs 
MIA: A Comparison of RIR Statistics and RIS Reality, 
http://www.nanog.org/mtg-0510/wilhelm.html
[3] BGP Support for Four-octet AS Number Space, 
draft-ietf-idr-as4bytes-12.txt

Timetable for implementation: Procedures to support this proposal need 
to be implemented by 1 January 2007