The correct conclusion is that CUSTOMER_A and CUSTOMER_B are on the same physical interface but different subinterfaces. This is determined by interpreting the "show vrf brief" output, which lists each VRF with its route distinguisher, protocols, and associated interfaces. The key technical detail is that both CUSTOMER_A and CUSTOMER_B are mapped to subinterfaces of GigabitEthernet0/0 (Gi0/0.100 and Gi0/0.200), while MANAGEMENT uses a separate physical interface Gi0/1, confirming they share the same parent port. On the ENCOR 350-401 exam, this command tests your ability to quickly identify VRF-to-interface bindings and understand that VRFs can be segmented on subinterfaces without requiring dedicated physical ports. A common trap is assuming each VRF needs its own physical interface, but the output clearly shows multiple VRFs sharing a single physical link through 802.1Q tagging. For a memory tip, remember "same port, different dot" — if the interface names differ only by the decimal after the slash, they are subinterfaces on the same physical port, not separate cables.
CCNP Infrastructure Security Practice Question
This 350-401 practice question tests your understanding of infrastructure security. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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 runs the following command on Router R1:
Why wrong: Each VRF has a different RD: 65000:100, 65000:200, and 65000:999.
B
The MANAGEMENT VRF is used for customer traffic.
Why wrong: MANAGEMENT is likely for out-of-band management, not customer traffic.
C
CUSTOMER_A and CUSTOMER_B are on the same physical interface but different subinterfaces.
Both are on Gi0/0 with different subinterfaces (.100 and .200), indicating they share the same physical port.
D
The router is running MPLS L3VPN.
Why wrong: While VRFs are used in MPLS L3VPN, the output does not show any MPLS protocols or BGP VPNv4, so it could be for other purposes like VRF-lite.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
CUSTOMER_A and CUSTOMER_B are on the same physical interface but different subinterfaces.
The output shows three VRFs: CUSTOMER_A, CUSTOMER_B, and MANAGEMENT. Each has a route distinguisher and is associated with specific interfaces. The CUSTOMER_A and CUSTOMER_B VRFs are on subinterfaces of GigabitEthernet0/0, while MANAGEMENT is on a separate physical interface.
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.
✗
All VRFs are using the same route distinguisher.
Why it's wrong here
Each VRF has a different RD: 65000:100, 65000:200, and 65000:999.
✗
The MANAGEMENT VRF is used for customer traffic.
Why it's wrong here
MANAGEMENT is likely for out-of-band management, not customer traffic.
✓
CUSTOMER_A and CUSTOMER_B are on the same physical interface but different subinterfaces.
Why this is correct
Both are on Gi0/0 with different subinterfaces (.100 and .200), indicating they share the same physical port.
Related concept
Read the scenario before looking for a memorised answer.
✗
The router is running MPLS L3VPN.
Why it's wrong here
While VRFs are used in MPLS L3VPN, the output does not show any MPLS protocols or BGP VPNv4, so it could be for other purposes like VRF-lite.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Trap categories for this question
Command / output trap
While VRFs are used in MPLS L3VPN, the output does not show any MPLS protocols or BGP VPNv4, so it could be for other purposes like VRF-lite.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 practitioner preparing for the 350-401 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which 350-401 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Infrastructure Security — This question tests Infrastructure Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: CUSTOMER_A and CUSTOMER_B are on the same physical interface but different subinterfaces. — The output shows three VRFs: CUSTOMER_A, CUSTOMER_B, and MANAGEMENT. Each has a route distinguisher and is associated with specific interfaces. The CUSTOMER_A and CUSTOMER_B VRFs are on subinterfaces of GigabitEthernet0/0, while MANAGEMENT is on a separate physical interface.
What should I do if I get this 350-401 question wrong?
Identify which 350-401 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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