CCNP Virtualization Practice Question
A network administrator is configuring a Cisco Nexus 9000 switch to participate in a VXLAN EVPN fabric. The administrator needs to define the source IP address used for VXLAN tunnels. Which interface should be configured as the source for the VXLAN tunnel?
⚠ Common exam trap
The trap here is choosing a port-channel or physical interface for redundancy, but a loopback is still the best practice for VTEP source because it is not tied to physical ports.
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
✓
A loopback interface with a /32 mask
The VXLAN tunnel source should be a loopback interface with a /32 mask. This ensures a stable, always-up source IP address that is independent of physical link failures. Using a physical interface, SVI, or port-channel can cause tunnel instability if the underlying links or VLANs go down.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A switched virtual interface (SVI) for the management VLAN
Why it's wrong here
An SVI is used for routing between VLANs and is typically associated with a VLAN that may not be present on all switches. Using a management SVI as the tunnel source can lead to reachability issues if the VLAN is not trunked everywhere. A dedicated loopback is preferred for VTEP source.
- ✗
A physical uplink interface
Why it's wrong here
Using a physical interface as the VXLAN tunnel source is not recommended because if that interface goes down, the tunnel fails. Physical interfaces can also change state, causing instability. A loopback provides a stable, always-up source address that is independent of physical link status.
- ✗
A port-channel interface
Why it's wrong here
A port-channel provides link redundancy but is still a logical interface that depends on physical members. If all members fail, the port-channel goes down, affecting the tunnel. While better than a single physical link, it does not offer the same stability as a loopback, which is not tied to any physical port.
- ✓
A loopback interface with a /32 mask
Why this is correct
VXLAN tunnels use a loopback interface as the source to ensure high availability and stability. A /32 loopback is always up and not tied to a physical port, so the tunnel source remains reachable even if a link fails. This is the recommended design for VTEPs in a VXLAN EVPN fabric.
Visual reference
About these practice questions
This 350-401 question is part of Courseiva's 1,923-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam 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.