Troubleshoot long ASN issues - Amazon Direct Connect
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Troubleshoot long ASN issues

If you are experiencing issues with long ASN configurations, use the following steps to troubleshoot:

BGP session fails with a long ASN

Symptoms: BGP session cannot establish after configuring a long ASN

Cause: On-premises router may not support long ASN capability

Resolution:

  • Verify your router supports RFC 6793

  • Check BGP configuration for consistent ASN format

  • Review BGP logs for capability negotiation errors

API responses show ASN as 0

Symptoms: API responses display asn field as 0

Cause: This is expected behavior when actual ASN exceeds 2,147,483,647

Resolution: Use the asnLong field in API responses for the correct ASN value

Migration from ASN to long ASN issues

Symptoms: Connectivity loss during ASN migration

Cause: BGP session re-establishment required for ASN changes

Resolution:

  • Plan migration during maintenance windows

  • Update one virtual interface at a time

  • Monitor BGP session status during changes

  • Verify routing table convergence after migration

If you continue to experience issues with long ASN configurations after following these troubleshooting steps, contact Amazon Support with the following information:

  • Virtual interface ID or BGP peer ID

  • Configured ASN values (both ASN and long ASN)

  • Router model and software version

  • BGP configuration and logs

  • Error messages or symptoms observed