VXLAN VNI Not Operational: Troubleshooting Missing NVE Interface Mapping
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?
Quick Answer
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.
⚠ Common exam trap
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.
Answer choices
Why each option matters
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.
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.
- ✗
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.
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Same concept, more angles
1 more way this is tested on 350-601
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.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-601 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 350-601 exam.