Question 166 of 239 from exam 200-301: Implementing and Administering Cisco Solutions

Question 166 of 239 from exam 200-301: Implementing and Administering Cisco Solutions

Question

When using Rapid PVST+, which command guarantees the switch is always the root bridge for VLAN 200?

Answers

Explanations

A. B. C. D.

B

When using the Rapid PVST+ (Per-VLAN Spanning Tree Plus) protocol, switches in a network exchange information about the best path to the root bridge for each VLAN. This information is used to determine the forwarding path for data frames in each VLAN. The root bridge is the switch that has the lowest priority value for a particular VLAN.

To guarantee that a switch is always the root bridge for VLAN 200, you would need to configure its priority value to be the lowest possible. The four answer choices provide different priority values for VLAN 200. Here's an explanation of each:

A. spanning-tree vlan 200 priority 614440 This command sets the priority value for VLAN 200 to 614440. This value is not the lowest possible, so it does not guarantee that the switch will be the root bridge for VLAN 200.

B. spanning-tree vlan 200 priority 0 This command sets the priority value for VLAN 200 to 0, which is the lowest possible value. Therefore, this command guarantees that the switch will always be the root bridge for VLAN 200.

C. spanning-tree vlan 200 root primary This command configures the switch to try to become the root bridge for VLAN 200 by setting its priority value to the lowest possible and sending out BPDUs (Bridge Protocol Data Units) to announce its candidacy. However, if there is already a switch with a lower priority value for VLAN 200, that switch will remain the root bridge.

D. spanning-tree vlan 200 priority 38813258 This command sets the priority value for VLAN 200 to 38813258. This value is not the lowest possible, so it does not guarantee that the switch will be the root bridge for VLAN 200.

Therefore, the correct command to guarantee that the switch is always the root bridge for VLAN 200 is B. spanning-tree vlan 200 priority 0.