Question 1easymultiple choice
Full question →easymultiple choiceObjective-mapped
What problem does Spanning Tree Protocol solve in a switched network?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
IP address exhaustion
STP does not address IP address planning.
B
Best answer
Layer 2 switching loops
Correct. Loop prevention is the core purpose of STP.
C
Distractor review
Slow DNS lookups
DNS performance is unrelated to STP.
D
Distractor review
Weak wireless encryption
Wireless encryption is unrelated to STP.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is selecting answers related to Layer 3 or higher-layer issues such as IP address exhaustion or DNS lookup delays, which are unrelated to STP’s function. Candidates may mistakenly think STP handles wireless encryption or IP management because these topics are common in networking but are outside STP’s scope. The key is to remember that STP specifically prevents Layer 2 switching loops by blocking redundant paths, not addressing IP or wireless security problems. Misunderstanding this can lead to incorrect answers and confusion during the exam.
Technical deep dive
How to think about this question
The Spanning Tree Protocol (STP) is a Layer 2 network protocol designed to prevent switching loops in Ethernet networks. Switching loops occur when there are multiple active paths between switches, causing broadcast frames to circulate endlessly, which leads to broadcast storms and MAC address table instability. STP dynamically identifies redundant links and selectively blocks some of these links to create a loop-free logical topology while maintaining physical redundancy for fault tolerance. STP operates by electing a root bridge and calculating the shortest path to the root for each switch port. It assigns port roles such as root port, designated port, and blocked port based on path cost metrics. Ports that could cause loops are placed into a blocking state, preventing frame forwarding on those links. This process ensures that only one active path exists between any two network devices at Layer 2, eliminating loops without manual intervention. A common exam trap is confusing STP’s purpose with Layer 3 issues like IP address management or DNS performance. STP strictly addresses Layer 2 switching loops and does not affect IP routing or wireless security. In practical Cisco networks, STP is essential for maintaining stable Layer 2 topologies, especially in environments with redundant links. Understanding STP’s role helps avoid misconfigurations that could cause network outages or broadcast storms.
KKey Concepts to Remember
- Spanning Tree Protocol prevents Layer 2 switching loops by selectively blocking redundant paths in a switched network.
- STP elects a root bridge and determines the shortest path to the root to assign port roles and prevent loops.
- Ports that could cause loops are placed into a blocking state to stop frame forwarding on redundant links.
- STP maintains physical redundancy while ensuring a loop-free logical topology for stable Ethernet switching.
- STP does not address Layer 3 issues such as IP address exhaustion or DNS lookup performance.
- Broadcast storms and MAC address table instability occur if switching loops are not prevented by STP.
- Cisco switches use STP by default to automatically manage redundant links and prevent network outages.
- Understanding STP’s loop prevention is critical for designing resilient and stable Layer 2 switched networks.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
Spanning Tree Protocol prevents Layer 2 switching loops by selectively blocking redundant paths in a switched network.
What is the correct answer to this question?
The correct answer is: Layer 2 switching loops — STP prevents Layer 2 loops by blocking redundant paths when necessary, which avoids broadcast storms and MAC table instability.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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