Loadbalancer.org glossary
Floating IP address
What is a Floating IP Address (FIP)?
A floating IP address is a highly available IP address that is only present on the active appliance. In a clustered pair, all floating IP addresses will “float” across and be added to the other appliance during a failover.
A FIP is automatically created when a virtual service is defined in order to provide high availability in the event of a failover.