Cisco Certified Network Professional Practice Test 2025 – Your All-in-One Guide to Exam Success!

The command that adjusts the VLAN bridge priority to root primary is "spanning-tree vlan vlan-id root primary." This command serves a specific function in the Spanning Tree Protocol (STP) configuration for VLANs.

When you implement this command, you are instructing the switch to take on the role of the root bridge if it is configured with the lowest bridge ID. By designating a VLAN's bridge priority as "root primary," you're effectively ensuring that this switch will have a higher chance of being elected as the root bridge for the specified VLAN. The priority value for the root bridge is critical in determining the topology of the network, as the switch with the lowest bridge ID (which is the combination of the bridge priority and the MAC address) becomes the root bridge.

This command is particularly useful in network designs where you want specific switches to take precedence in the STP topology, allowing for more control over the path selection and redundancy. In scenarios with multiple switches, leveraging this command helps to optimize the network path, minimizing potential loops and improving overall network stability by strategically making certain switches the designated root bridges.