CCNA Switching and Network Access Practice Question
What problem does Spanning Tree Protocol solve in a switched network?
⚠ Common exam trap
Avoid confusing STP with technologies like EtherChannel, IPsec, or QoS, which address different network concerns.
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
✓
Layer 2 switching loops
STP prevents Layer 2 loops by blocking redundant paths when necessary, which avoids broadcast storms and MAC table instability.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
IP address exhaustion
Why it's wrong here
IP address exhaustion refers to the depletion of available IPv4 addresses, a network-layer scaling problem typically mitigated with VLSM, NAT, and IPv6 adoption. STP operates at Layer 2 and only manages Ethernet forwarding paths; it has no mechanism to assign, conserve, or extend IP address space, so it cannot address limitations in addressing.
When this WOULD be correct
In a question asking about the challenges of IPv4 addressing in a large network or the implications of subnetting, option A could be correct if it discusses the depletion of available IP addresses due to insufficient subnetting or address planning.
- ✓
Layer 2 switching loops
Why this is correct
Spanning Tree Protocol (IEEE 802.1D) eliminates Layer 2 switching loops by placing redundant switch ports in a blocking state, leaving a single active loop-free path between hosts. Without STP, broadcast frames cycle endlessly, creating broadcast storms, MAC address flapping, and duplicated unicast frames that severely degrade the switching fabric. Redundant links remain available and are activated automatically if the primary path fails.
- ✗
Slow DNS lookups
Why it's wrong here
Slow DNS lookups stem from application-layer resolution delays caused by unresponsive DNS servers, high recursion time, or packet loss between the client and resolver. This is purely a name-resolution performance issue independent of data-link layer topology. STP is a Layer 2 protocol that manages broadcast-domain loop prevention and does not influence the timing or path of DNS queries.
When this WOULD be correct
In a different exam question asking about network performance issues, if the question specifically relates to factors affecting application response times, such as slow DNS resolution due to misconfigured DNS servers, option C could be correct. For example, a question might ask about the causes of slow website loading times, where DNS lookups are a factor.
- ✗
Weak wireless encryption
Why it's wrong here
Weak wireless encryption involves insufficient authentication or confidentiality protections on Wi-Fi networks, typically remedied by implementing WPA2/WPA3 with AES-CCMP and robust key management. STP runs on Ethernet switches and bridges, governing loop-free forwarding on wired segments; it has no effect on over-the-air encryption, cipher suites, or wireless security policy.
When this WOULD be correct
If the exam question asked about security protocols in wireless networks, specifically regarding encryption methods like WPA2 or WPA3, then 'weak wireless encryption' could be the correct answer in the context of discussing vulnerabilities in wireless security.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Layer 2 switching loopsCorrect answer▾
Why this is correct
Spanning Tree Protocol (IEEE 802.1D) eliminates Layer 2 switching loops by placing redundant switch ports in a blocking state, leaving a single active loop-free path between hosts. Without STP, broadcast frames cycle endlessly, creating broadcast storms, MAC address flapping, and duplicated unicast frames that severely degrade the switching fabric. Redundant links remain available and are activated automatically if the primary path fails.
✗IP address exhaustionWrong answer — click to see why▾
Why this is wrong here
Spanning Tree Protocol (STP) operates at Layer 2 and has no mechanism to manage or allocate IP addresses; IP address exhaustion is addressed by protocols like DHCP or IPv6 transition technologies.
★ When this WOULD be the correct answer
In a question asking about the challenges of IPv4 addressing in a large network or the implications of subnetting, option A could be correct if it discusses the depletion of available IP addresses due to insufficient subnetting or address planning.
Why candidates choose this
Students might confuse STP with routing protocols or think that any network protocol can help with IP address management, but STP is strictly for loop prevention.
✗Slow DNS lookupsWrong answer — click to see why▾
Why this is wrong here
DNS lookups are application-layer processes that rely on IP connectivity and name resolution servers; STP does not influence DNS performance or resolution speed.
★ When this WOULD be the correct answer
In a different exam question asking about network performance issues, if the question specifically relates to factors affecting application response times, such as slow DNS resolution due to misconfigured DNS servers, option C could be correct. For example, a question might ask about the causes of slow website loading times, where DNS lookups are a factor.
Why candidates choose this
A test-taker might think that network loops cause slow DNS due to broadcast storms, but STP's primary role is loop prevention, not DNS optimization.
✗Weak wireless encryptionWrong answer — click to see why▾
Why this is wrong here
Wireless encryption is a security feature implemented at the data link layer (e.g., WPA2/3) and is unrelated to STP, which deals with physical topology loop prevention.
★ When this WOULD be the correct answer
If the exam question asked about security protocols in wireless networks, specifically regarding encryption methods like WPA2 or WPA3, then 'weak wireless encryption' could be the correct answer in the context of discussing vulnerabilities in wireless security.
Why candidates choose this
Students may associate 'spanning tree' with wireless mesh networks or confuse STP with security protocols, but STP is specifically for wired Ethernet switches.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
Go deeper
Related to this question
Learn chapter
Interpreting Packet Capture Output for Layer 2/3 Troubleshooting
Key term
MAC
MAC (Media Access Control) is a unique hardware identifier assigned to network interfaces for communication on a local network segment.
Key term
STP
STP (Spanning Tree Protocol) is a network protocol that prevents loops in Ethernet networks by creating a loop-free logical topology.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 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 200-301 exam.