[SRX] The chassis cluster does not failover if the 'ae' aggregate interface is configured under 'interface-monitor'

Summary:

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

Symptoms:

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;
			}
		}

Cause:

The chassis cluster interface failover supports only physical interfaces.

Solution:

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.

The final configuration is:

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; ==>
}
}

For more information about the supported configuration on the chassis cluster, refer to the following link:

http://www.juniper.net/techpubs/en_US/junos11.1/information-products/topic-collections/security/software-all/security/index.html?topic-47219.html

For additional information, refer to TN10 - SRX High Availability Deployment Guide (Chassis Cluster configuration examples).

For more information about the aggregate interface on an EX switch, refer to KB22474 - Link aggregation (LACP) supported/non-supported configurations on SRX and EX.

Knowledge Base