This 350-601 practice question tests your understanding of network. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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
show interface nve 1
nve1 is up
Interface-Address: 10.1.1.1/24
NVE Mode: L3VPN
Source Interface: loopback0
Number of VNIs: 3
VNI 10010: UP
VNI 10020: UP
VNI 10030: DOWN
show nve vni 10030
VNI 10030 (L3VPN)
Associated VLAN: none
Operational State: DOWN
mcast group: 239.1.1.1
Refer to the exhibit. A VXLAN VNI (10030) is operationally down. What is the most likely cause?
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.
show interface nve 1
nve1 is up
Interface-Address: 10.1.1.1/24
NVE Mode: L3VPN
Source Interface: loopback0
Number of VNIs: 3
VNI 10010: UP
VNI 10020: UP
VNI 10030: DOWN
show nve vni 10030
VNI 10030 (L3VPN)
Associated VLAN: none
Operational State: DOWN
mcast group: 239.1.1.1
A
The source interface loopback0 is not up
Why wrong: The exhibit shows NVE interface is up, so loopback0 is up.
B
The NVE mode should be L2VPN instead of L3VPN
Why wrong: L3VPN mode is valid; L2VPN would be for bridging; the mode does not cause the VNI to be down.
C
The VLAN associated with VNI 10030 is not configured or mapped
The VNI must be mapped to a VLAN using 'vn-segment vlan-id' under the VLAN configuration; missing mapping causes operational down.
D
The multicast group 239.1.1.1 is not reachable
Why wrong: If multicast group were unreachable, the VNI might show up but traffic would not forward; the VNI state would still be UP.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The VLAN associated with VNI 10030 is not configured or mapped
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.
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.
✗
The source interface loopback0 is not up
Why it's wrong here
The exhibit shows NVE interface is up, so loopback0 is up.
✗
The NVE mode should be L2VPN instead of L3VPN
Why it's wrong here
L3VPN mode is valid; L2VPN would be for bridging; the mode does not cause the VNI to be down.
✓
The VLAN associated with VNI 10030 is not configured or mapped
Why this is correct
The VNI must be mapped to a VLAN using 'vn-segment vlan-id' under the VLAN configuration; missing mapping causes operational down.
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 multicast group 239.1.1.1 is not reachable
Why it's wrong here
If multicast group were unreachable, the VNI might show up but traffic would not forward; the VNI state would still be UP.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that a VNI goes down due to multicast reachability or source interface issues, but the actual cause is the missing VLAN-to-VNI mapping, which is a common misconfiguration in VXLAN deployments.
Trap categories for this question
Command / output trap
The exhibit shows NVE interface is up, so loopback0 is up.
Detailed technical explanation
How to think about this question
Under the hood, the NVE interface maintains a mapping between VNIs and VLANs via the `member vni` command. The operational state of a VNI depends on the existence of the associated VLAN in the VLAN database; if the VLAN is absent, the VNI remains in a 'down' state even if the NVE interface is up. In real-world scenarios, this often occurs when a VLAN is deleted or not created before configuring VXLAN, leading to traffic blackholing for that segment. The `show nve vni` command reveals the operational state, and `show vlan` confirms whether the VLAN exists.
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 help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
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: The VLAN associated with VNI 10030 is not configured or mapped — 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.
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.
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