prop-032: 4-byte AS number policy proposal

Proposal text



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 4-byte AS number space.

Current status

Policy implemented.


Geoff Huston

Relevant forum

Policy SIG

Most recent version


Previous versions


Status at other RIRs

Proposal history



15 December 2005

Version 1 announced to mailing list

2 March 2006

Version 2 reached consensus at APNIC 21 Policy SIG and AMM

17 March 2006 – 12 May 2006

Version 2 in 8 week final call for comments

9 May 2006

Proposal adopted by ARIN Board of Trustees

14 July 2006

Endorsed by EC

11 September 2006

Ratified by LACNIC Directory

1 December 2006

Draft policy document released

1 January 2007

First phase of policy implemented: four-byte ASNs assigned on request.

APNIC will make four-byte AS number assignments from the range:

  • 2.0 – 2.1023

AS number syntax will be the APNIC Whois Database has been extended to accommodate four-byte AS numbers. This may affect any automated tools you use to interact with the database. The changes affect the following database objects:

  • aut-num
  • as-block
  • as-set
  • filter-set
  • inet-rtr
  • peering-set
  • route
  • route6
  • route-set
  • rtr-set

Please note that syntax for two-byte AS numbers remains unchanged.

See also:

1 January 2009

Second phase of policy to be implemented: two-byte ASNs assigned on request

1 January 2010

Final phase of policy to be implemented: four-byte ASNs assigned by default