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Autonomous System number (ASN) resource guide

Definition

Autonomous System numbers (ASNs) are globally unique identifiers for Autonomous Systems. An Autonomous System (AS) is a group of IP networks having a single clearly defined routing policy, run by one or more network operators.

News

On 1 January, 2007 APNIC began processing applications for both two-byte and four-byte AS numbers. The request form has been updated to reflect this change. APNIC still assigns two-byte AS numbers by default, so if you require a four-byte AS number, please specify this in your request form.

APNIC makes four-byte AS number assignments from the range:

• 2.0 - 2.1023

AS number syntax in 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 will remain unchanged.

See also:

• Policy document Policies for Autonomous System number management in the Asia Pacific region
  
• APNIC resource ranges
• Canonical Textual Representation of 4-byte AS Numbers (IETF Internet draft)
• BGP Support for Four-octet AS Number Space (IETF Internet draft)

Contents

• Policy and AS number information
• Request form

Policy and AS number information

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