350-601 Network Practice Question
In a VXLAN overlay, what is the role of the VXLAN Network Identifier (VNI)?
⚠ Common exam trap
It's easy for candidates to confuse the VNI with the multicast group address used for BUM traffic, but the VNI is a segment identifier, not a multicast address; Cisco often tests this by listing 'multicast group' as a distractor to see if you understand the separation of overlay identification from underlay forwarding.
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
✓
It identifies the overlay Layer 2 network segment
The VXLAN Network Identifier (VNI) is a 24-bit field in the VXLAN header that uniquely identifies an overlay Layer 2 network segment, allowing multiple isolated Layer 2 domains to coexist over a shared Layer 3 underlay. It is analogous to a VLAN ID in traditional networking but provides up to 16 million segments, enabling scalable network virtualization.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
It identifies the VXLAN tunnel source and destination IP
Why it's wrong here
Tunnel endpoints are VTEP IPs, not VNI.
- ✓
It identifies the overlay Layer 2 network segment
Why this is correct
VNI uniquely identifies a Layer 2 segment across the overlay.
- ✗
It is the multicast group address for BUM traffic
Why it's wrong here
Multicast group is separate; VNI is just the network identifier.
- ✗
It is used for ECMP load balancing
Why it's wrong here
ECMP uses outer header fields like IP and UDP ports.
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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.