CCNP Infrastructure Practice Question
A network engineer is implementing VXLAN with a Cisco Nexus 9000 series switch acting as a VTEP. The underlay network is OSPF, and the overlay uses BGP EVPN. The engineer notices that VM traffic between two hosts on different VTEPs is not being encapsulated. Which action should be taken to ensure VXLAN traffic is properly encapsulated and forwarded?
⚠ Common exam trap
Test-takers frequently confuse underlay routing issues with overlay encapsulation; the lack of encapsulation is due to missing NVE configuration, not OSPF or BGP.
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
✓
Enable VXLAN feature and configure the NVE interface with a source interface and a VNI mapping to the VLAN.
VXLAN encapsulation requires the NVE interface to be configured with a source interface and VNI-to-VLAN mapping. Enabling the VXLAN features and configuring the NVE interface are essential steps. Without these, the switch will not encapsulate traffic, even if the underlay and overlay routing are correct.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Ensure that the underlay OSPF cost is equal on all links to allow ECMP for VXLAN traffic.
Why it's wrong here
While ECMP in the underlay can improve VXLAN traffic distribution, it is not required for encapsulation. The problem is that VXLAN encapsulation is not occurring, which points to a missing NVE interface or feature enablement. Equal OSPF costs would not fix a lack of encapsulation.
- ✗
Configure a VRF for the overlay and redistribute the VRF routes into OSPF.
Why it's wrong here
VRF and route redistribution are relevant for tenant routing, but the issue is that VXLAN encapsulation is not happening at all. The missing piece is the NVE interface configuration. Redistributing VRF routes into OSPF would not create the VXLAN tunnel or enable encapsulation.
- ✓
Enable VXLAN feature and configure the NVE interface with a source interface and a VNI mapping to the VLAN.
Why this is correct
To enable VXLAN encapsulation, the `feature nv overlay` and `feature vn-segment-vlan-based` must be enabled, and an NVE interface must be configured with a source interface (usually a loopback) and a VNI mapped to the VLAN. The NVE interface is the VTEP, and without it, VXLAN encapsulation does not occur.
- ✗
Configure a VXLAN tunnel interface with the source interface as the loopback0 and the destination as the remote VTEP's loopback0.
Why it's wrong here
VXLAN on Nexus 9000 with EVPN uses a dynamic VXLAN tunnel interface, not static tunnels. The tunnel destination is learned via BGP EVPN, not manually configured. Static tunnel configuration is used in older VXLAN implementations without EVPN, but it does not scale and is not the recommended method for EVPN-based VXLAN.
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
About these practice questions
Courseiva writes every 350-401 question from scratch — 1,923 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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.