CCNP Virtualization Practice Question
A data center uses Cisco Nexus 9000 switches with VXLAN EVPN to provide network virtualization. The operations team notices that VLAN 100 (mapped to VNI 10100) is not reachable across the fabric, although other VLANs work fine. The NVE interface is up, and the EVPN address-family is configured. Which two actions should the engineer take to isolate the issue?
⚠ Common exam trap
Cisco often tests the distinction between control-plane (BGP EVPN) and data-plane (multicast) VXLAN, leading candidates to incorrectly check multicast reachability (Option B) when the issue is a missing or inconsistent VNI configuration.
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
✓
Verify that VLAN 100 is mapped to VNI 10100 consistently on all VTEPs.
VXLAN EVPN requires consistent VLAN-to-VNI mapping across all VTEPs in the fabric. If VLAN 100 is mapped to VNI 10100 on some switches but not others, traffic for that VNI will not be forwarded correctly, as the mapping is used to associate local VLANs with the VXLAN segment. Option D is correct because the VNI must be explicitly enabled under the NVE interface to participate in VXLAN tunnel termination; without it, the VTEP will not encapsulate or decapsulate traffic for VNI 10100.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Check if EVPN type-3 routes are being advertised for VNI 10100.
Why it's wrong here
Type-3 routes are for multicast, not for unicast MAC/IP.
- ✗
Confirm that multicast group 239.1.1.1 is reachable across the underlay.
Why it's wrong here
EVPN uses BGP, not multicast.
- ✓
Verify that VLAN 100 is mapped to VNI 10100 consistently on all VTEPs.
Why this is correct
Inconsistent mapping breaks VXLAN bridging.
- ✓
Ensure that VNI 10100 is added under the NVE interface.
Why this is correct
VNI must be member of NVE to forward traffic.
- ✗
Check if the MTU on the underlay is set to at least 1550 bytes.
Why it's wrong here
MTU issue would affect all VNIs, not just one.
Visual reference
About these practice questions
Courseiva writes every 350-401 question from scratch — 1,175 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 by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.