Learn to create and configure control interfaces in HA deployments.
    Generation One ION devices use the control port to exchange HA heartbeat
                and manage the controller traffic between the active and the standby device. With
                the introduction of 
used-for-HA (referred to as
                Used-for-Control in earlier release) as a port type, the NextGen ION devices such as
                the ION 1200-S, ION 3200, ION 5200, ION 9200 do not need a dedicated controller port
                for the management services. 
The used-for-HA interface allows you to exchange HA
                heartbeat and connect the standby device to the controller through the active ION
                device, centralizing all management and control traffic. You can use the control
                interface to send management traffic like App Probe, NTP, SNMP, RADIUS, and IPFIX. 
Support for used-for-HA capability is extended on the
                main interface on all routed ports. This capability was available on SVI and
                sub-interfaces in the previous release. Used for HA is supported on all the ION
                devices.