The answer is that VNI 10000 is not configured under the NVE interface. This is the most likely reason traffic fails to encapsulate because the NVE interface acts as the tunnel endpoint for VXLAN; without the explicit `member vni 10000` command under `interface nve1`, the switch has no mapping to associate that VNI with the overlay encapsulation process. Even if the VNI exists elsewhere in the network, the local NVE simply does not know to handle it. On the Cisco DCCOR and CCNP Data Center Core 350-601 exam, this scenario tests your understanding of the fundamental NVE-to-VNI binding requirement—a common trap is assuming a VNI is active just because it is defined in the global VNI database. Remember the memory tip: "No member, no encapsulator"—if a VNI is not a member of the NVE, it will never be encapsulated.
350-601 Network Practice Question
This 350-601 practice question tests your understanding of network. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
Exhibit
interface nve1
no shutdown
source-interface loopback0
member vni 20000 associate-vrf red
member vni 30000 associate-vrf blue
Refer to the exhibit. A network engineer notices that traffic for VNI 10000 is not being encapsulated. What is the most likely reason?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
VNI 10000 is not configured under the nve interface.
VNI 10000 must be explicitly mapped to an NVE interface under the 'interface nve1' configuration using the 'member vni 10000' command. Without this mapping, the NVE interface does not know which VNI to encapsulate traffic for, even if the VNI exists in the network. Option B correctly identifies this missing configuration as the most likely cause.
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.
✗
BGP EVPN is not configured.
Why it's wrong here
Encapsulation does not require BGP; static VXLAN could work.
✓
VNI 10000 is not configured under the nve interface.
Why this is correct
The show output clearly does not include member vni 10000.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The VRF association is incorrect.
Why it's wrong here
Not relevant as VNI 10000 is missing entirely.
✗
The source-interface is not reachable.
Why it's wrong here
The source-interface loopback0 is configured and assumed reachable.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between control-plane (BGP EVPN) and data-plane (NVE interface) configurations, trapping candidates who assume that a VNI configured in the VRF or advertised via EVPN automatically enables encapsulation on the NVE interface.
Detailed technical explanation
How to think about this question
In VXLAN/EVPN deployments, the NVE interface is the logical termination point for VXLAN tunnels, and each VNI must be explicitly added as a member under 'interface nve1' with the 'member vni <vni>' command. The 'source-interface' defines the tunnel source IP, but it is a global parameter for all VNIs on that NVE; a missing VNI member entry means the NVE will not encapsulate frames for that VNI, regardless of other configurations. In real-world scenarios, this often occurs when a new VNI is provisioned in the network but the NVE interface is not updated, leading to silent traffic drops.
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 practitioner preparing for the 350-601 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 exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Network — This question tests Network — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: VNI 10000 is not configured under the nve interface. — VNI 10000 must be explicitly mapped to an NVE interface under the 'interface nve1' configuration using the 'member vni 10000' command. Without this mapping, the NVE interface does not know which VNI to encapsulate traffic for, even if the VNI exists in the network. Option B correctly identifies this missing configuration as the most likely cause.
What should I do if I get this 350-601 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Refer to the exhibit. A VXLAN VNI (10030) is operationally down. What is the most likely cause?
medium
A.The source interface loopback0 is not up
B.The NVE mode should be L2VPN instead of L3VPN
✓ C.The VLAN associated with VNI 10030 is not configured or mapped
D.The multicast group 239.1.1.1 is not reachable
Why C: VXLAN VNI 10030 is operationally down because the VLAN that maps to this VNI is either not created or not associated with the VNI under the NVE interface. In Cisco NX-OS, a VNI becomes operationally up only when the corresponding VLAN exists and is properly mapped via the `member vni 10030 associate-vrf` or `member vni 10030` command under the NVE interface. Without this mapping, the NVE cannot forward traffic for that VNI, leaving it in a down state.
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Question Discussion
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