Configuring SSB Redundancy on the M20 Router
For M20 routers with two System and Switch Boards (SSBs), you can configure which SSB is the master and which is the backup. By default, the SSB in slot 0 is the master and the SSB in slot 1 is the backup. To modify the default configuration, include the ssb statement at the [edit chassis redundancy] hierarchy level:
slot-number is 0 or 1.
always defines the SSB as the sole device.
preferred defines a preferred SSB.
To manually switch mastership between SSBs, issue the request chassis ssb master switch command.
To display SSB status information, issue the show chassis ssb command. The command output displays the number of times the mastership has changed, the SSB slot number, and the current state of the SSB: master, backup, or empty. For more information, see the Junos OS Operational Mode Commands.
