This article describes the issue of the SRX chassis cluster not failing over, when the ae aggregate interface is configured under interface-monitor .

The chassis cluster may not failover, if one of the physical interfaces goes down; even though they have 255 as the defined weight and the ae interface is also being monitored.

redundancy-group 1 {
		node 0 priority 254;
		node 1 priority 245;
		preempt;
		interface-monitor {
			ge-0/0/2 weight 255;
			ge-0/0/3 weight 255;
			ae1 weight 255; < ae1 is being monitored for failover
		}
	}

	interface-range ae1-members {
			member ge-0/0/0;
			member ge-0/0/1;
			enable;
			traps;
			gigether-options {
				802.3ad ae1;
			}
		}
	 

The chassis cluster interface failover supports only physical interfaces.

• The chassis cluster interface failover supports only physical interfaces.
• The logical interface should not be defined in interface-monitor . This will cause confusion in the failover logic and the weight will not decrement from 255; so failover will not occur.
• Remove the ae1 interface from the interface-monitor and add the child interface of ae1 in there.

redundancy-group 1 {
    node 0 priority 254;
    node 1 priority 245;
    preempt;
interface-monitor {
    ge-0/0/2 weight 255;
    ge-0/0/3 weight 255;
    ge-0/0/0 weight 255; ==> Child interfaces of 'ae1' are added here; instead of the 'ae1' logical interface
    ge-0/0/1 weight 255; ==>
}
}