A network technician receives a ticket from an employee who is working on PC 1...

Switch 1

spanning-tree vlan 10 root primary

spanning-tree vlan 20 root secondary

Switch 2

spanning-tree vlan 20 root primary

spanning-tree vlan 10 root secondary

This PBQ is pointing to a switching loop / MAC flapping problem. The biggest clues are the high CPU utilization and the fact that the MAC table is continuously changing. That behavior is classic for a Layer 2 loop when redundant links exist between switches and no proper spanning-tree root role has been established.

The available commands shown in the screenshots are limited to spanning-tree vlan, so this is not an interface shutdown question. The fix is to use STP per VLAN and make one switch the preferred root for one VLAN and the other switch the preferred root for the other VLAN. That prevents both uplinks from forwarding in an uncontrolled loop while still giving redundancy.

A clean design is:

Switch 1 root primary for VLAN 10

Switch 2 root primary for VLAN 20

Make each opposite switch root secondary for failover

That stabilizes Layer 2 forwarding, stops MAC address flapping, reduces CPU load, and restores normal connectivity. After applying the STP root settings, the user should be able to ping 192.168.1.31 from PC 1 successfully. If your simulator asks for validation, run the ping again from PC 1 to the database server.