Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


Replacing a T4000 LCC-CB


The router can have up to two LCC-CBs. They are located in the upper rear of the chassis in the slots marked CB0 and CB1. Each LCC-CB weighs approximately 5 lb (2.3 kg).


Before you replace a control board, you must take the host subsystem offline. The backup control board is hot-removable and hot-insertable. If the control board to be replaced is associated with the Routing Engine currently functioning as the master Routing Engine, switch the master to the backup before removing the control board. If there is only one host subsystem, taking the host subsystem offline shuts down the router.

  1. Taking the Host Subsystem Offline

  2. Removing a T4000 LCC-CB

  3. Installing a T4000 LCC-CB

Taking the Host Subsystem Offline

To take a host subsystem offline:

  1. Determine whether the host subsystem is functioning as the master or as the backup, using one of the two following methods:
    • Check the Routing Engine LEDs on the craft interface. If the green MASTER LED is lit, the corresponding host subsystem is functioning as the master.

    • Use the show chassis routing-engine command to determine which Routing Engine is the master. In this example, the master Routing Engine in Slot 0 is designated Master in the Current state field:

      user@host> show chassis routing-engine
  2. If the host subsystem is functioning as the master, switch it to backup using the CLI command:
    user@host> request chassis routing-engine master switch
  3. To halt the router:
    user@host> request system halt

    If two Routing Engines are installed, also issue the command on the backup Routing Engine. Wait until a message appears on the console confirming that the operating system has halted.

    The command shuts down the Routing Engine cleanly, so its state information is preserved.


    The SIBs might continue forwarding traffic for approximately 5 minutes after the request system halt command has been issued.

  4. To take the control board offline, issue the following command.
    user@host> request chassis cb offline slot n

    n is 0 or 1 for the slot number of the host subsystem being taken offline.

  5. Verify that the control board is offline:
    user@host> show chassis environment cb 0

Removing a T4000 LCC-CB

To remove an LCC-CB (see Figure 1):

  1. Place an electrostatic bag or antistatic mat on a flat, stable surface.
  2. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
  3. Loosen the captive screws (using a Phillips (+) screwdriver, number 2) on the ejector handles on both sides of the LCC-CB faceplate.
  4. Flip the ejector handles outward to unseat the LCC-CB.
  5. Grasp the ejector handles, and slide the LCC-CB about halfway out of the chassis.
  6. Place one hand underneath the LCC-CB to support it, and slide it completely out of the chassis.
  7. Place the LCC-CB on the antistatic mat.
  8. If you are not replacing the LCC-CB now, install a blank panel over the empty slot.
Figure 1: Removing an LCC-CB
Removing an LCC-CB

Installing a T4000 LCC-CB

To install an LCC-CB (see Figure 2):

  1. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
  2. Verify that the CHASSIS ID and M/S switches on the LCC-CB faceplate are set correctly for your configuration. If you are installing the LCC-CB in a standalone router, the M/S switch must be set to S and the CHASSIS ID configuration switch must be set to 0.Note

    See Setting the Chassis ID and M/S Switch on the LCC-CB in the TX Matrix Plus Router Hardware Guide for instructions to set the switches when installing the LCC-CB in a T4000 that is part of a routing matrix.

  3. Carefully align the sides of the LCC-CB with the guides inside the chassis.
  4. Slide the LCC-CB into the chassis, carefully ensuring that it is correctly aligned.
  5. Grasp both ejector handles, and press them inward to seat the LCC-CB.
  6. Tighten the captive screws on the ejector handles, using a Phillips (+) screwdriver, number 2.
  7. Verify that the LCC-CB is functioning normally:

    • Check the LEDs on the LCC-CB faceplate. The green OK LED should light steadily a few minutes after the LCC-CB is installed. If power is applied to the Routing Engine and its corresponding LCC-CB is functioning normally, the LCC-CB comes online automatically.

      If the FAIL LED is lit steadily, remove and install the LCC-CB again. If the FAIL LED still lights steadily, the LCC-CB is not functioning properly. Contact your customer support representative.

    • Use the show chassis environment cb command to check the status of the LCC-CB.

      show chassis environment cb
Figure 2: Installing an LCC-CB
Installing an LCC-CB

See also