[sig-policy] prop-032-v001: 4-byte AS number policy proposal
Dear SIG members,
The following "4-byte AS number policy proposal" was received. Please feel
free
to review and comment on the proposal. Please also sumit your proposal for
APNIC21 meeting.
Regards
Kenny Huang
Policy SIG
huangk at alum dot sinica dot edu
________________________________________________________________________
prop-032-v001: 4-byte AS number policy proposal
________________________________________________________________________
Authors: Geoff Huston
Version: 1
Date: 15 December 2005
SIG: Policy
Introduction
-------------
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.
Summary
-------
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.
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.
Background
----------
Recent studies of AS number consumption rates indicate that the existing
2-byte 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]. Standardisation 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 4-byte field [3].
It is noted that some advance period may be required by network operators to
undertake the appropriate procedures relating to support of 4-byte 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 2-byte AS number exhaustion date.
Nomenclature
------------
It is proposed to identify 4-byte AS numbers using a syntax of <high order
16 bit value in decimal>.<low order 16 bit value in decimal>.
Accordingly, a 4-byte AS number of value 65546 (decimal) would be identified
as "1.10".
Terminology
-----------
2-byte only AS numbers: AS numbers in the range 0 - 65535
4-byte only AS numbers: AS numbers in the range 1.0 - 65535.65535
(decimal range 65,536 - 4,294,967,295)
4-byte AS numbers: AS numbers in the range 0.0 - 65535.65535
(decimal range 0 4,294,967,295)
Proposal
--------
This policy proposal nominates 3 dates for changes to the current AS number
allocation policy for the registry:
1. On 1 January 2007 the registry will process applications that
specifically request 4-byte only AS Numbers and allocate such AS
numbers as requested by the applicant. In the absence of any
specific request for a 4-byte only AS number, a 2-byte only AS
number will be allocated by the registry.
2. On 1 January 2009 the registry will process applications that
specifically request 2-byte only AS numbers and allocate such AS
numbers as requested by the applicant. In the absence of any
specific request for a 2-byte only AS number, a 4-byte only AS
number will be allocated by the registry.
3. On 1 January 2010 the registry will cease to make any distinction
between 2-byte only AS numbers and 4-byte only AS numbers, and will
operate AS number allocations from an undifferentiated 4-byte AS
number allocation pool.
No other changes in AS number allocation policy are implied by this
proposal.
Pros/cons
---------
The policy provides a clear indication of dates at which time 4-byte AS
numbers will be available for use, and a date by which the transition to use
of a larger 4-byte AS number pool is anticipated to be completed.
Effect on APNIC
---------------
This policy proposal is intended to respond to the predicted exhaustion of
2-byte AS numbers by proposing an orderly and clearly predictable transition
for APNIC members to the use of 4-byte AS numbers.
References
----------
[1] Daily AS Number Report, http://www.potaroo.net/tools/asns
[2] ASNs MIA: A Comparision 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