Command to Verify GRES Operational

B

The show system switchover command, which is used to verify whether graceful Routing Engine switchover is enabled and that the databases are synchronized, must be issued on the backup RE to get the desired output.

The correct answer to verify that graceful Routing Engine Switchover (GRES) is operational is option A: show system switchover on the master RE.

When a graceful Routing Engine Switchover (GRES) occurs, the system automatically switches from the primary Routing Engine (RE) to the backup RE without disrupting network traffic. The GRES feature maintains the same forwarding state information and protocols running on the primary RE by transferring them to the backup RE, which helps to minimize any impact on network performance.

To verify that GRES is operational, you can use the following command on the master RE:

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show system switchover 

This command displays information about the status of GRES on the master RE. If GRES is operational, the output will show a message similar to the following:

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Routing Engine status:     Slot 0:         Current state                  Master         Election priority              Backup (default)         Temperature                 34 degrees C / 93 degrees F         DRAM                       2048 MB         Memory utilization          24 percent         CPU utilization:           User                       0 percent           Background                 0 percent           Kernel                     1 percent           Interrupt                  0 percent           Idle                      98 percent         Model                          RE-VMX         Serial ID                      8000000         Start time                     2019-01-01 00:00:00 UTC         Uptime                         1 hour, 21 minutes, 34 seconds         Last reboot reason             0x100:power cycle/failure         Load averages:                 1 minute   5 minute  15 minute                                           0.02       0.06       0.02 

If GRES is not operational, the output will show a message similar to the following:

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Routing Engine status:     Slot 0:         Current state                  Master         Election priority              Master (default)         Temperature                 33 degrees C / 91 degrees F         DRAM                       2048 MB         Memory utilization          25 percent         CPU utilization:           User                       1 percent           Background                 0 percent           Kernel                     1 percent           Interrupt                  0 percent           Idle                      98 percent         Model                          RE-VMX         Serial ID                      8000000         Start time                     2019-01-01 00:00:00 UTC         Uptime                         1 hour, 21 minutes, 34 seconds         Last reboot reason             0x100:power cycle/failure         Load averages:                 1 minute   5 minute  15 minute                                           0.01       0.05       0.02     Error: HA status check is not ready 

Option B, show system switchover on the backup RE, will display information about the status of GRES on the backup RE. This command is not useful for verifying that GRES is operational on the system as a whole.

Option C, show task replication on the master RE, displays information about the replication status of tasks running on the master RE. This command is not related to GRES and does not verify that GRES is operational.

Option D, show task replication on the backup RE, displays information about the replication status of tasks running on the backup RE. This command is not related to GRES and does not verify that GRES is operational.