This article describes the issue of second control link failure on 3400/3600 SRX chassis cluster. 

Dual Control Links are configured on 3000 SRX Series Chassis Cluster, with one CRM installed on each member. The second control link does not work.

Symptoms:

Not able to activate the redundant control link. We can see both the devices are sending signals on the second control link, but not receiving any on either end.

{primary:node0}
root@SRX3400-1> show chassis cluster control-plane statistics
Control link statistics:
Control link 0:
Heartbeat packets sent: 453055
Heartbeat packets received: 453053
Heartbeat packet errors: 0
Control link 1:
Heartbeat packets sent: 453055
Heartbeat packets received: 0
Heartbeat packet errors: 0
Fabric link statistics:
Probes sent: 453053
Probes received: 452789
Probe errors: 0

{secondary:node1}
root@SRX3400-2> show chassis cluster control-plane statistics
Control link statistics:
Control link 0:
Heartbeat packets sent: 899571
Heartbeat packets received: 899379
Heartbeat packet errors: 0
Control link 1:
Heartbeat packets sent: 899571
Heartbeat packets received: 0
Heartbeat packet errors: 0
Fabric link statistics:
Probes sent: 899569
Probes received: 898851
Probe errors: 0

Second control LED stays green even when the fiber cable is removed. Second Control LED should have gone dark or stopped glowing, as shown in the images below:

1. If you are not using Juniper certified SFP modules on HA1 ports, please change them to Juniper certified.

2. If the problem still exists, replace the CRM on the node that has the problem.

• Refer to the SRX3400 Services Gateway Hardware Guide (Chapter 12: Replacing Hardware Components on the SRX3400 Services Gateway).

• A list of certified SFP modules.

2020-07-02: Article reviewed for accuracy; Minor changes added to highlight identifying problem state and link for certified SFP modules.