Core Issue
A Border Gateway Protocol (BGP) Autonomous System (AS) is identified by a number in the range 1 to 65535. AS numbers in the range 1 to 64511 are assigned by InterNIC. These are reserved and globally unique AS numbers. AS numbers in the range 64512 to 65535 are known as private AS numbers, and like private IP addresses, these can be used to address ASs when a globally unique AS number is not necessary. It is important to ensure that the private AS numbers are not introduced into the global BGP table through the AS-Path attribute.
Resolution
To remove the private AS numbers from the AS-Path attribute in outbound routing updates, issue the neighbor remove-private-as command in router configuration mode.
For more information and configuration examples, refer to Sample Configuration for Removing Private AS Numbers in BGP.
For infomation on the conditions necessary for the command to work properly, refer to Removing Private Autonomous System Numbers in BGP.
