ASN32 FAQs

1. What is an ASN32?
2. Why have ASN32s been introduced?
3. When can I start using an ASN32?
4. Why should I ask for an ASN32?
5. Where can I find out more about ASN32s?
6. Will the allocation policy change?
7. I already have an AS Number, do I need to apply for a new one?
8. How do I apply for a temporary ASN32 to test my network?
9. What is the format of an ASN32?
10. How will the Routing Policy Specification Language (RPSL) change?
11. Are ASN32s only available in RIPE NCC service region?
12. Should I request an ASN16 or ASN32?
13. How can I get an ASN32?
14. What will (mp-)import/export/default attributes in my aut-num object look like if I or my peers use ASN32?

1. What is an ASN32?

ASN32 stands for 32-bit (4-byte) Autonomous System Number (ASN).

2. Why have ASN32s been introduced?

With 16-bit (2-byte) AS Numbers (ASN16), around 65,000 unique numbers are possible. Approximately 40,000 of these numbers have already been allocated. Studies have shown that with the present allocation rate, the supply of ASN16s will be exhausted between 2010 and 2015. ASN32 increases the supply of AS Numbers to four billion.

3. When can I start using an ASN32?

You were able to request ASN32s from 1 January, 2007. However, if you do not specifically ask for an ASN32 after this date, you will still receive an ASN16. As of 1 January, 2009, all allocations will be ASN32, unless you specifically ask for an ASN16. From 1 January 2010, only ASN32s will be allocated.

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4. Why should I ask for an ASN32?

So that you are prepared. ASN32s will appear on the Internet from 1 January 2007 and you will be allocated an ASN32 every time you apply for an ASN for a new customer after 1 January 2009. You will see ASN32s in your peering scripts and database queries.

5. Where can I find out more about ASN32s?

The following Internet Engineering Task Force (IETF) documents offer more information about ASN32s:

• http://www.ietf.org/internet-drafts/draft-ietf-idr-as4bytes-12.txt
  This document describes the changes to the BGP protocol and the ASN16 to ASN32 transition mechanism.

• http://www.ietf.org/internet-drafts/draft-michaelson-4byte-as-representation-02.txt
  This document describes the formatting of ASN32.

• http://www.ietf.org/internet-drafts/draft-uijterwaal-rpsl-4byteas-ext-01.txt
  This document describes the changes to RPSL necessary for ASN32.

Note: These documents are "works in progress" and may be replaced by a newer version at any time.

6. Will the allocation policy change?

No, the criteria for allocation of an ASN will not change.

See PDP 2005-12 for more details:

• http://www.ripe.net/ripe/policies/proposals/2005-12.html
  

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7. I already have an AS Number, do I need to apply for a new one?

No. ASN16s and ASN32s are interoperable. You do not have renumber. If you do not plan to expand your network it is sufficient to check that your tools still work when you enter an ASN32 (using s/ASx.y/AS23456/). More details are available at:

• http://ripe.net/ripe/meetings/ripe-53/presentations/32bit_asn.pdf

8. How do I apply for a temporary ASN32 to test my network?

You can apply for an ASN32 using the experimental allocation policy. Information on this policy is available at:

• https://www.ripe.net/ripe/docs/asn-assignment.html#11

9. What is the format of an ASN32?

The format for ASN32s is discussed in the following document:

• http://ietfreport.isoc.org/idref/draft-michaelson-4byte-as-representation/

It will also be discussed further in the IETF Inter-Domain Routing WG.

The current format is ASy for ASN16 and ASx.y for ASN32, with x representing the higher 16 bits in decimal and y the lower. Please be aware, however, that this format may change.

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10. How will the Routing Policy Specification Language (RPSL) change?

RPSL has been extended to allow for ASN32s. RPSL will use ASy for ASN16 and ASx.y for ASN32.

All RPSL extensions supporting ASN32s are described in the following document:

• http://www.ietf.org/internet-drafts/draft-uijterwaal-rpsl-4byteas-ext-01.txt

11. Are ASN32s only available in RIPE NCC service region?

No. All of the Regional Internet Registries (RIRs) are working on the implementation.

12. Should I request an ASN16 or ASN32?

If you want to use your ASN immediately, and you are using slightly older equipment, apply for an ASN16. If you are flexible about when you need to start using your ASN, or you are using the latest equipment, apply for an ASN32.

13. How can I get an ASN32?

You should fill in the ASN request form:

• http://www.ripe.net/ripe/docs/asnrequestform.html

Supporting information for this request for is available at:

• http://www.ripe.net/ripe/docs/asnsupport.html

Specify your need for a 32-bit ASN under [INSERT SUPPLEMENTAL COMMENTS].

14. What will (mp-)import/export/default attributes in my aut-num object look like if I or my peers use ASN32?

RPSL extensions to support ASN32 are described here: http://www.ietf.org/internet-drafts/draft-uijterwaal-rpsl-4byteas-ext-01.txt

This document also describes the changes in format of other RPSL classes, such as "aut-num", "as-set", "route-set" and "route".