You are reviewing the configuration of a VSX LAG and have noticed the command LACP...

The LACP fallback command in Aruba VSX configurations allows the system to continue forwarding traffic even if LACP negotiation fails or is not established. This is useful when provisioning a gateway or link that does not support LACP, ensuring that the port remains operational in a static manner.

It is not specifically for backward compatibility with LACP v1.

It does not relate to operation with a single partner interface.

It also is not about active/passive LACP modes per se.

Therefore, LACP fallback is configured to support provisioning a gateway without LACP.