IPsec tunnel to secondary controller
ArubaOS-Switch assists support for IPsec tunnel between switch and the Aruba Controller (VPN concentrator) to carry the switch generated traffic to multiple services behind the Aruba Controller. The services include AirWave management station, ClearPass, DNS, Syslog, and so on.
IPsec tunnel needs a backup support for IPsec session failure. If the existing IPsec session is lost, the switch is able to establish a new IPsec tunnel session with a backup controller (secondary controller).