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request chassis ssb master switch



(M20 router only) Control which System and Switch Board (SSB) is primary.



(Optional) Do not request confirmation for the switch.

Additional Information

By default, the SSB in slot 0 (SSB0) is the primary and the SSB in slot 1 (SSB1) is the backup. If you use this command to change the primary, and then restart the chassis software for any reason, the primary reverts to the default setting. To change the default primary SSB, include the ssb statement at the [edit chassis redundancy] hierarchy level in the configuration. For more information, see the Junos OS Administration Library for Routing Devices.

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 primaries, when the chassis software restarts for any reason, the SSB in slot 0 becomes the primary and the one in slot 1 becomes the backup.

The switchover from the primary SSB to the backup SSB is immediate. The SSB takes several seconds to reinitialize the Flexible PIC Concentrators (FPCs) and restart the PICs. The interior gateway protocol (IGP) and BGP convergence times depend on the specific network environment.

Required Privilege Level


Output Fields

When you enter this command, you are provided feedback on the status of your request.

Sample Output

request chassis ssb primary switch

request chassis ssb primary switch no-confirm

Release Information

Command introduced before Junos OS Release 7.4.