Preemt delay timer

A failover delay timer is introduced on SRX Series devices in a chassis cluster to limit the flapping of redundancy group state between the secondary and the primary nodes in a preemptive failover. Back-to-back failovers of a redundancy group in a short interval can cause the cluster to exhibit unpredictable behavior because of flapping of the active and backup systems. To prevent this, a delay timer can be configured to delay the immediate failover for a configured period of time--between 1 and 21,600 seconds. In addition, you can configure the preemptive limit to restrict the number of failovers (1 to 50) in a given time period (1 to 1440 seconds) when preemption is enabled for a redundancy group. This enhancement enables the administrator to introduce a failover delay, which can reduce the number of failovers and result in a more stable network state due to the reduction in active / backup flapping within the redundancy group.