Quick Answer
The correct conclusion is that VRF CUSTOMER-B is associated with subinterface GigabitEthernet0/1.20. This is directly confirmed by the "show vrf brief" command output, which lists each VRF name alongside its assigned interfaces in the rightmost column; for CUSTOMER-B, the interface column shows GigabitEthernet0/1.20, while CUSTOMER-A is mapped to GigabitEthernet0/1.10. The command also displays the Route Distinguisher (RD) and supported protocols, but the key takeaway for VRF interpretation is that the interface column explicitly ties each VRF to its Layer 3 termination point. On the ENCOR 350-401 exam, this tests your ability to read VRF configurations quickly and avoid the trap of confusing the Default RD column with interface assignments—many candidates mistakenly focus on the RD values instead of the interface mapping. A reliable memory tip is to think of "show vrf brief" as a VRF-to-interface cheat sheet: read left to right, and always verify the last column for the physical or subinterface binding.
This 350-401 practice question tests your understanding of wan technologies. 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 R7:
R7# show vrf brief
Name Default RD Protocols Interfaces Mgmt-intf <not set> ipv4,ipv6 GigabitEthernet0/0 CUSTOMER-A 65001:100 ipv4 GigabitEthernet0/1.10 CUSTOMER-B 65001:200 ipv4 GigabitEthernet0/1.20
Based on this output, what can be concluded?
VRF CUSTOMER-A is using IPv6.
Why wrong: The protocols column shows only ipv4 for CUSTOMER-A.
VRF Mgmt-intf has a route distinguisher set.
Why wrong: The Default RD for Mgmt-intf is '<not set>'.
VRF CUSTOMER-B is associated with subinterface GigabitEthernet0/1.20.
The output shows CUSTOMER-B with interface GigabitEthernet0/1.20.
All VRFs are using the same route distinguisher.
Why wrong: Each VRF has a different RD.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
VRF CUSTOMER-B is associated with subinterface GigabitEthernet0/1.20.
The output shows VRFs with route distinguishers and associated interfaces. VRF CUSTOMER-A and CUSTOMER-B are configured with specific RDs and interfaces.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
VRF CUSTOMER-A is using IPv6.
Why it's wrong here
The protocols column shows only ipv4 for CUSTOMER-A.
VRF Mgmt-intf has a route distinguisher set.
Why it's wrong here
The Default RD for Mgmt-intf is '<not set>'.
VRF CUSTOMER-B is associated with subinterface GigabitEthernet0/1.20.
Why this is correct
The output shows CUSTOMER-B with interface GigabitEthernet0/1.20.
Related concept
Read the scenario before looking for a memorised answer.
All VRFs are using the same route distinguisher.
Why it's wrong here
Each VRF has a different RD.
Common exam traps
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
The protocols column shows only ipv4 for CUSTOMER-A.
Detailed technical explanation
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.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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
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.
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FAQ
WAN Technologies — This question tests WAN Technologies — Read the scenario before looking for a memorised answer..
The correct answer is: VRF CUSTOMER-B is associated with subinterface GigabitEthernet0/1.20. — The output shows VRFs with route distinguishers and associated interfaces. VRF CUSTOMER-A and CUSTOMER-B are configured with specific RDs and interfaces.
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.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 18, 2026
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.
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