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[SRX] Troubleshooting steps to correct a Control Link down situation in a Chassis Cluster



Article ID: KB20698 KB Last Updated: 29 Sep 2020Version: 8.0

The article helps to resolve a Chassis Cluster 'down' issue, due to the Control Link failing to come up.

This article is part of the Resolution Guide -- SRX Chassis Cluster (High Availability).


Chassis Cluster is down due to the Control Link being down.

Run the following command to check if the Control Link is down:

Sample output:

For a Branch series SRX services gateway device:

root@J-SRX> show chassis cluster interfaces
Control link 0 name: fxp1

Control link status: Down

For a High End series SRX services gateway device:

root@J-SRX> show chassis cluster interfaces
Control link 0 name: em0
Control link 1 name: em1

Control link status: Down

Perform the following steps to troubleshoot and correct a Control Link down:

  1. Do you have a switch in between the two Chassis Cluster nodes for the Control Link?

    • Yes - Continue to Step 2
    • No - Go to Step 3
  2. Remove the switch and try a direct connection of the control ports. Now reboot the secondary node.

    Are the Control Links still down?
  3. Is the interface link light GREEN for control link on both nodes?

    • Yes - Go to Step 5.
    • No -  Continue with Step 4.
  4. Change the cable that you are using for control link. Is the interface link light GREEN now?

    • Yes - Previous link cable was faulty. Recommend to now reboot both the nodes simultaneously. Did the control link come up after the reboot? If no, then continue to Step 5
    • No - Go to Step 8.
  5. Is this device a SRX 5600 or SRX 5800 service gateway device?

    • Yes - Continue with Step 6.
    • No - Check if you have the correct physical ports connected. Refer to KB15356 - Chassis Cluster Ports Details for SRX Series for your device.

      Once the correct ports are connected for the control link, if still seeing issue then proceed to Step 7.

  6. Reconfigure the control link port to a different SPC, move the cable and reboot both nodes. Is the control link up?

    • Yes - Possible hardware issue with SPC. Continue to Step 8.
    • No - Continue to Step 7.
  7. If the Control Link is SFP-type port, change the transceiver on both ends. Ensure that the transceivers are same type (LX, SX, etc.) and that they are Juniper-branded parts. Is the Control Link up now?  

    • Yes - Possible faulty transceiver issue. RMA may be required for the transceivers. Continue to Step 8.
    • No - Continue to Step 8.
  8. Follow steps in KB21781 - [SRX] Data Collection Checklist - Logs/data to collect for troubleshooting and open a case with your technical support representative.

    Collect the following information for JTAC (collect from both nodes of the Chassis Cluster).

    show chassis cluster status
    show chassis cluster statistics
    show chassis cluster information
    show log jsrpd
    show log messages
    show log chassisd
    request support information
Modification History:
2020-09-29: Updated the link in step 5.
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