The set-system-state ACLI command provides the ability to temporarily place a clustered SBC in the offline state. The offline setting puts the SBC into a state where it is powered on and available only for administrative purposes.

The transition to the offline state is graceful in that existing calls are not affected by the state transition. The SBC informs the Subscriber-Aware Load Balancer of the impending status change via a CCP message. Upon receiving such a message, the Subscriber-Aware Load Balancer ceases to forward new endpoints to the SBC, and places the SBC in the Shutdown state. The SBC, for its part, enters a state that results in the rejection of any incoming out-of-dialog SIP requests. Eventually all calls compete, registrations expire and are removed by the Subscriber-Aware Load Balancer, and returning endpoints are allotted to active SBCs.

Use the set-system-state offline ACLI command to place an SBC in the offline state.

ORACLE# set-system-state offline
Are you sure you want to bring the system offline? [y/n]?: y
Setting system state to going-offline, process will complete when all current calls have completed
ORACLE#

In a similar fashion use the set-system-state online ACLI command to place an SBC in the online state.

ORACLE# set-system-state online
Are you sure you want to bring the system online? [y/n]?: y
Setting system state to online
ORACLE#