You have configured your switches with the spanning-tree vlan x root primary and spanning-tree vlan x root secondary commands. Which tertiary switch will take over if both switches fail?

Question

Group of answer choices

A switch with priority 20480

A switch with priority 4096

A switch with priority 8192

A switch with priority 12288

Answer 1

When configuring a switch as a Spanning Tree Protocol (STP) root bridge, the switches are given priorities that determine their role in the tree. The lower the bridge priority value, the higher the likelihood that the switch will be elected as the root bridge.

In your scenario, you have two commands configured:

1. spanning-tree vlan x root primary — This sets the priority of the switch to 24576 (values are specific to switch models and firmware but typically yield a bridge priority of 32768 minus the specified increments).
2. spanning-tree vlan x root secondary — This sets the priority of the second switch to 28672.

If both of these switches fail, the next root bridge will be chosen based on the next lowest bridge priority in the remaining switches.

Given the options:

1. A switch with priority 20480
2. A switch with priority 4096
3. A switch with priority 8192
4. A switch with priority 12288

The switch with the lowest priority value that will take over when both the primary and secondary switches fail is:

A switch with priority 4096.

This is the lowest priority value and will thus become the root bridge under the given scenario.