STP Troubleshooting STP

Question 1

What is a broadcast storm in a switched network?

Accepted Answer

Continuous flooding of broadcast frames caused by a Layer 2 loop, consuming all bandwidth

Answer

A broadcast storm occurs when frames loop endlessly through redundant paths, multiplying exponentially and consuming all network bandwidth.

Question 2

How do you verify the current STP root bridge?

Accepted Answer

Use show spanning-tree command to display root bridge ID, priority, and port roles

Answer

The show spanning-tree command displays the root bridge information, local bridge details, and port states and roles.

Question 3

What are common symptoms of an STP failure?

Accepted Answer

Network slowness, high CPU on switches, MAC address table instability, broadcast storms

Answer

STP failures typically manifest as network-wide performance issues caused by looping traffic overwhelming switch resources.

Question 4

How do you change the STP root bridge priority?

Accepted Answer

Configure a lower bridge priority value on the desired root bridge switch

Answer

Setting a lower priority value (e.g., 4096) ensures the desired switch wins the root bridge election.

Question 5

What happens when a root bridge fails in STP?

Accepted Answer

A new root bridge election occurs using the bridge with the next lowest bridge ID

Answer

When the root bridge fails, the network automatically elects a new root bridge based on the next lowest bridge ID.

(STP) Spanning Tree Protocol Practice Test