Before you remove a Routing Engine, remove the cables that connect to it.
![]() | Caution: Before you replace a Routing Engine, you must take the host subsystem offline. If there is only one host subsystem, taking the host subsystem offline shuts down the router. |
![]() | Caution: If the Routing Engine to be replaced is currently functioning as the master Routing engine, switch it to be the backup before removing it. |
To remove a Routing Engine from an SCB (see Figure 1):
![]() | Note: To maintain proper airflow through the chassis, do not leave an SCB installed in the chassis without a Routing Engine for extended periods of time. If a Routing Engine is removed, a replacement Routing Engine should be installed as soon as possible. |
Figure 1: Removing a Routing Engine

To install a Routing Engine into an SCB (see Figure 2):
The Routing Engine might require several minutes to boot.
After the Routing Engine boots, verify that it is installed correctly by checking the RE0 and RE1 LEDs on the craft interface. If the router is operational and the Routing Engine is functioning properly, the green ONLINE LED lights steadily. If the red FAIL LED lights steadily instead, remove and install the Routing Engine again. If the red FAIL LED still lights steadily, the Routing Engine is not functioning properly. Contact your customer support representative.
To check the status of the Routing Engine, use the CLI command:
user@host> show chassis routing-engineRouting Engine status: Slot 0: Current state Master ...
For more information about using the CLI, see the Junos OS documentation.
Figure 2: Installing a Routing Engine
