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    Switch SSB Mastership

    To change the default master SSB, include the ssb statement at the [edit chassis redundancy] hierarchy level in the configuration. For more information, see the Junos OS System Basics Configuration Guide.

    To control which SSB is master, use the following command:

    user@host> request chassis ssb master switch <no-confirm>
    user@host> request chassis ssb master switch
    warning: Traffic will be interrupted while the PFE is re-initialized
    Toggle mastership between system switch boards ? [yes,no] (no) yes
    Switch initiated, use “ show chassis ssb”  to verify
    

    By default, the SSB in slot 0 (SSB0) is the master and the SSB in slot 1 (SSB1) is the backup.

    Note: For routers that have two SSBs, both SSBs must be running Junos OS Release 4.0 or later. Do not run Junos OS Release 3.4 on one of the SSBs and Junos OS Release 4.0 or later on the other.

    Junos OS Release 3.4 does not support SSB redundancy; if you are using this release of the software, only one SSB can be installed in the router. It can be installed in either slot.

    The configurations on the two SSBs do not have to be the same, and they are not automatically synchronized. If you configure both SSBs as masters, when the chassis software restarts for any reason, the SSB in slot 0 becomes the master and the SSB in slot 1 becomes the backup.

    Published: 2012-08-20