Long ASN support in AWS Direct Connect - AWS Direct Connect
ConsiderationsAvailability and Pricing

Long ASN support in AWS Direct Connect

Support for long ASNs (4-byte) allows you to configure long Autonomous System Numbers (ASNs) as part of the parameters of the BGP session established between the AWS network device and your network device. This feature is enabled or disabled on a per-account basis.

You can set the an ASN or Long ASN range on either the console or through the APIs.

  • When using the console, the ASN field supports both ASNs and long ASNs. You can add any range from 1 to 4294967294.

  • When using the APIs to create a virtual interface, you can specify either an ASN (asn) or the Long ASN (asnLong) but not both. For more information on using ASN or Long ASN, see the following APIs in the AWS Direct Connect API Reference:

    • BGPPeer

    • DeleteBGPPeerRequest

    • NewBGPPeer

    • NewPrivateVirtualInterface

    • NewPrivateVirtualInterfaceAllocation

    • NewPublicVirtualInterface

    • NewPublicVirtualInterfaceAllocation

    • NewTransitVirtualInterface

    • NewTransitVirtualInterfaceAllocation

    • VirtualInterface

Considerations

When choosing to use either an ASN or a long ASN, note the following:

  • Backward compatibility: Direct Connect automatically handles BGP sessions with both ASN and long ASN-capable routers. If your router doesn't support long ASNs, the BGP session will operate in ASN mode.

  • ASN format: You can specify 4-byte ASNs in either asplain format —for example, 4200000000 or asdot format — for example, 64086.59904. Direct Connect accepts both formats but displays ASNs in asplain format

  • Private ASN ranges: When using private long ASNs (4200000000-4294967294), the same replacement behavior applies as with private ASNs. Direct Connect will replace your private ASN with 7224 when advertising to other networks.

  • BGP community tags: All existing BGP community tags (7224:xxxx) work with long ASNs. The community tag format remains unchanged.

  • Monitoring and troubleshooting: CloudWatch metrics, BGP session logs, and troubleshooting tools display long ASNs in asplain format for consistency.

Availability and Pricing

Note the following for long ASN support with AWS Direct Connect:

  • Availability: Long ASN is available in all AWS Regions where AWS Direct Connect is supported.

  • Pricing: There are no additional charges for long ASN support beyond standard AWS Direct Connect pricing.

Note

Long ASN enablement applies to your entire AWS account. You cannot enable long ASN support for individual virtual interfaces or BGP peers.