mediumMultiple Choice
350-401 Practice Question: Runs the following command on Switch SW6: SW6#…
A network engineer runs the following command on Switch SW6:
SW6# show spanning-tree vlan 60
VLAN0060 Spanning tree enabled protocol ieee Root ID Priority 24636 Address aabb.cc00.0a00 Cost 8 Port 1 (GigabitEthernet0/1) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768 (priority 32768 sys-id-ext 60) Address aabb.cc00.0b00 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- ------------------------------ Gi0/1 Root FWD 8 128.1 P2p Gi0/2 Desg FWD 4 128.2 P2p Gi0/3 Altn BLK 4 128.3 P2p Gi0/4 Desg FWD 4 128.4 P2p
Based on this output, what is the bridge priority of the root bridge for VLAN 60?
⚠ Common exam trap
Cisco often tests whether candidates understand that the 'Priority' field in the 'Root ID' section includes the system ID extension (VLAN ID), so the displayed value is not the base priority but the combined value, leading many to incorrectly subtract the VLAN ID when the question simply asks for the value as shown.
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
✓
24636
The root bridge's priority is shown in the 'Root ID' section as 'Priority 24636'. This value includes the system ID extension (VLAN 60), so the actual bridge priority is 24636 - 60 = 24576. However, the question asks for the bridge priority as displayed in the output, which is 24636. Option B is correct because the output explicitly lists the root bridge priority as 24636.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
24576
Why it's wrong here
24576 is the 'base' bridge priority (0x6000) before the VLAN system ID extension is added. In PVST/Rapid PVST, the 16-bit priority field is a combination of a 4-bit base priority (in increments of 4096) and a 12-bit system ID (the VLAN ID), so the total root priority would be 24576 + 60 = 24636 for VLAN 60. The 'show spanning-tree' output displays the extended value, 24636, not 24576; therefore this option is incorrect.
- ✓
24636
Why this is correct
The Root ID priority in the output is 24636, which is the complete 16-bit priority value formed by the base priority (24576, or 0x6000) plus the VLAN system ID extension (60, or 0x003C). This value is lower than 32768, indicating that the root bridge has a higher priority (a lower numeric value) than the default, which is why it won the root election. Thus, 24636 is the correct answer.
- ✗
32768
Why it's wrong here
32768 (0x8000) is the default bridge priority of the local switch SW6, not the root bridge. The 'show spanning-tree' output's 'Bridge ID Priority' section lists 32768 for SW6, but the 'Root ID Priority' is a separate field with the value 24636. Since the question specifically asks for the root ID priority, this option is incorrect.
- ✗
32828
Why it's wrong here
32828 is not present anywhere in the 'show spanning-tree' output. It may be a distractor generated by adding the default priority (32768) to the VLAN ID (60), but the root bridge's priority is 24636, not 32828. No value in the output supports 32828, so this option is incorrect.
Visual reference
Go deeper
Related to this question
About these practice questions
One of 1,923 original 350-401 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.