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Maintaining the M120 FEBs



For optimum cooling, verify the condition of the FEBs.


On a regular basis:

  • Check the LEDs on the FEB faceplate. For more information on the FEB LEDs, see FEB LEDs.

  • Check the FEB LEDs on the craft interface to view information; see FEB LEDs on the Craft Interface.

  • Issue the CLI show chassis feb command to check the status of each of the installed FEBs. As shown in the sample output, the value Online in the column labeled State indicates that the FEB is functioning normally.

    user@host> show chassis feb

    For more detailed output, add the detail option. The following example also specifies a slot number (0), which is optional:

    user@host> show chassis feb detail 0

    You can also issue the show chassis environment feb command to check the status of a specific FEB. In the example below, the FEB is slot 0 is used. The output is similar to the following:

    user@host> show chassis environment feb 0
  • To take a FEB offline or online or restart it, click Offline, Online, enter the request chassis feb (online | offline | restart) slot slot-number command.


    If you bring a FEB offline (or remove it), interfaces on FPCs connected to the FEB are deleted. When you bring the FEB back online, the interfaces are restored.

  • Plan FEB redundancy groups according to your network requirements.

    A FEB redundancy group is a named collection of two or more Forwarding Engine Boards (FEBs) that can improve interface availability. You can design your redundant FEB configuration to provide backup on a one-to-one basis, or you can provide one backup for multiple FEBs. Each FEB redundancy group can contain only one primary FEB.

    To create or edit FEB redundancy groups, use the edit chassis redundancy feb-redundancy group group-name command.

  • Change the default assignments of FPCs to FEBs according to your network requirements. By default, each FPC is assigned to the FEB of the same identifying number; for example, FPC 1 is assigned to FEB 1.

    • To assign an FPC to a FEB, use the fpc-feb-connectivity statement at the [edit chassis] hierarchy level. You can also map an FPC to none to specify that the FPC is not mapped to any FEB. (When an FPC is configured not to connect to any FEB, interfaces on that FPC are not created; however, no alarm is triggered.)

    • To view which FPCs are mapped to which FEBs and the status of each link, enter the show chassis fpc-feb-connectivity command.

    For more information about FEB redundancy groups and FPC-to-FEB connectivity, see the Junos OS Administration Library.