350-401 Network Assurance Practice Question
A network administrator is troubleshooting a Cisco Catalyst switch and suspects a Layer 2 loop. The administrator wants to verify the Spanning Tree Protocol (STP) topology and identify the root bridge. Which command should be used?
⚠ Common exam trap
A common mix-up: candidates confuse MAC address table output with STP topology information; seeing the same MAC on multiple ports suggests a loop but does not confirm STP status.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
show spanning-tree
To verify STP topology and identify the root bridge, the 'show spanning-tree' command is the correct choice. It provides detailed output for each VLAN, including the root bridge ID, root path cost, and port roles. This allows the administrator to confirm the expected topology and detect any loops or misconfigurations.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
show mac address-table
Why it's wrong here
The 'show mac address-table' command displays the MAC address table, which can indicate a loop if the same MAC address appears on multiple ports. However, it does not directly show STP topology or root bridge information. It is useful for detecting MAC flapping but not for verifying STP operation.
- ✓
show spanning-tree
Why this is correct
The 'show spanning-tree' command displays the STP topology, including the root bridge, root port, designated ports, and port states. It is the primary command to verify STP operation and detect loops. On a Cisco Catalyst switch, this command provides detailed information for each VLAN, helping the administrator identify the root bridge and any blocked ports.
- ✗
show interfaces trunk
Why it's wrong here
The 'show interfaces trunk' command displays trunk port information, such as allowed VLANs and native VLAN, but does not provide STP topology details. It is used to verify trunk configuration, not to identify the root bridge or detect loops.
- ✗
show cdp neighbors
Why it's wrong here
The 'show cdp neighbors' command displays information about directly connected Cisco devices, such as platform and interface. It does not show STP topology or root bridge information. It is used for neighbor discovery, not for STP troubleshooting.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 350-401 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-401 exam.