You are here: Home > Participate > Policy Development > Policy Proposals > IANA Policy for Allocation of ASN Blocks to RIRs

This policy proposal has been accepted

DRAFT: Internet Assigned Numbers Authority (IANA) Policy for Allocation of ASN Blocks to Regional Internet Registries


This document describes the policy governing the allocation of Autonomous System Numbers (ASNs) from the IANA to the Regional Internet Registries (RIRs).

This policy document does not stipulate performance requirements in the provision of services by the IANA to an RIR. Such requirements will be specified by appropriate agreements between ICANN and the Number Resource Organization (NRO).

1. Allocation Principles

IANA allocates ASNs to RIRs in blocks of 1024 ASNs. In this document the term "ASN block" refers to a set of 1024 ASNs. Until 31 December 2009, allocations of 2-byte only and 4-byte only ASN blocks will be made separately and independent of each other.1 This means until 31 December 2009, RIRs can receive two separate ASN blocks, one for 2-byte only ASNs and one for 4-byte only ASNs from the IANA under this policy. After this date, IANA and the RIRs will cease to make any distinction between 2-byte only and 4-byte only ASNs, and will operate ASN allocations from an undifferentiated 4- byte ASN allocation pool.

2. Initial Allocations

Each new RIR will be allocated a new ASN block.

3. Additional Allocations

An RIR is eligible to receive (an) additional ASN block(s) from the IANA if one of the following conditions is met:

  1. The RIR has assigned 80% of the previously received ASN block
  2. The number of free ASNs currently held by the RIR is less than two months need. This projection is based on the monthly average number of ASNs assigned by the RIR over the previous six months.

An RIR will be allocated as many ASN blocks as are needed to support their registration needs for the next 12 months, based on their average assignment rate over the previous six months, unless the RIR specifically requests fewer blocks than that for which it qualifies.

4. Announcement of IANA Allocations

The IANA, the NRO and the RIRs will make announcements and update their respective websites/databases when an allocation is made by the IANA to an RIR. ICANN and the NRO will establish administrative procedures to manage this process.

Get Involved

The Address Policy Working Group develops policies relating to the allocation and registration of Internet number resources (IPv4 and IPv6 addresses and ASNs) by the RIPE NCC and its members. Anyone with an interest in Internet numbering issues is welcome to observe, participate and contribute to the WG. To post a message to the list, send an email to [email protected] Please note that only subscribers can post messages.

RIPE Forum

The RIPE Forum is an additional way to participate in RIPE community mailing list discussions using a web-based interface rather than an email client.

Check out the forum

Please contact if you need more information.

Stay up to date!

Follow @PDO_RIPE_NCC on Twitter.