The answer is to deploy two core switches configured with VSS or StackWise. This design is correct because VSS virtualizes two physical switches into a single logical entity, providing both redundancy and active-active load balancing at the campus core layer while eliminating the need for Spanning Tree Protocol on inter-switch links, which enables sub-second failover and maximizes throughput between distribution and core layers. On the ENCOR 350-401 exam, this concept tests your understanding of high-availability core designs and often appears as a distractor where a single chassis or traditional STP-based pair is offered as a trap. Remember that VSS and StackWise remove STP blocking and allow both uplinks to forward traffic simultaneously. A useful memory tip: VSS = Virtual Single Switch, meaning no STP blocking and both links active.
CCNP Architecture Practice Question
This 350-401 practice question tests your understanding of architecture. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network engineer is designing a campus network and needs to ensure high availability for the core layer. Which design best practice should be implemented?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Deploy two core switches configured with VSS or StackWise.
Option B is correct because deploying two core switches with VSS (Virtual Switching System) or StackWise provides both redundancy and active-active load balancing at the core layer. VSS virtualizes two physical switches into a single logical switch, eliminating the need for Spanning Tree Protocol (STP) on inter-switch links and enabling sub-second failover. This design ensures high availability by removing single points of failure and maximizing throughput between distribution and core layers.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Use a single distribution switch to simplify management.
Why it's wrong here
A single distribution switch is a single point of failure and not recommended for high availability.
✓
Deploy two core switches configured with VSS or StackWise.
Why this is correct
Dual core switches with VSS or StackWise provide redundancy and sub-second failover.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Configure the core layer for Layer 2 switching only.
Why it's wrong here
Layer 2 only in the core limits scalability and does not inherently provide high availability.
✗
Use spanning-tree PortFast on all core switch ports.
Why it's wrong here
Spanning-tree PortFast speeds up host connectivity but does not provide redundancy.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that the core layer should remain Layer 2 for simplicity, but in modern campus designs, the core must route at Layer 3 to avoid STP convergence delays and support ECMP load balancing.
Detailed technical explanation
How to think about this question
VSS uses a virtual switch link (VSL) to synchronize control planes between two chassis, presenting a single management IP and MAC address. In a VSS pair, STP is not needed on the inter-switch links because the pair acts as one logical switch, allowing all uplinks from distribution switches to remain forwarding. This design also supports Multi-Chassis EtherChannel (MEC), where a distribution switch can bundle links to both core switches for increased bandwidth and redundancy without STP blocking.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
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.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Architecture — This question tests Architecture — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Deploy two core switches configured with VSS or StackWise. — Option B is correct because deploying two core switches with VSS (Virtual Switching System) or StackWise provides both redundancy and active-active load balancing at the core layer. VSS virtualizes two physical switches into a single logical switch, eliminating the need for Spanning Tree Protocol (STP) on inter-switch links and enabling sub-second failover. This design ensures high availability by removing single points of failure and maximizing throughput between distribution and core layers.
What should I do if I get this 350-401 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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