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    T640 Control Boards Description

    Control Board Function

    This chassis supports up to two control boards. The Routing Engine requires an adjacent control board to provide control and monitoring functions for the router. These functions include determining Routing Engine mastership, controlling power and reset for the other router components, monitoring and controlling fan speed, and monitoring system status.

    Control Board Slots

    You can install up to two control boards in the router. Control boards install into the upper rear of the chassis in the slots labeled CB0 and CB1 (referred to as CB-0 and CB-1, top to bottom). If two control boards are installed, one functions as the master and the other as its backup. If the master fails or is removed, the backup restarts and becomes the master.

    Each control board requires a Routing Engine to be installed in the adjacent slot. CB0 installs above RE0, and CB1 installs below RE1. Control boards cannot function if a Routing Engine is not present in the adjacent slot.

    If the host system is redundant, the backup control board is hot-removable and hot-insertable, but the master control board is hot-pluggable. A control board that is not redundant is hot-pluggable.

    Control Boards Supported

    The T640 router supports the control boards listed in Table 1.

    Table 1: T640 Supported Control Boards


    Model Number

    First Supported Junos OS Release

    Standard control board (EOL PSN-2006-09-024)




    Note: The T-CB is required for T640 routers connected to a TX Matrix router.




    Note: The LCC-CB is not supported for T640 routers connected to a TX Matrix router.


    11.2 for standalone T640 routers.

    Published: 2013-08-20