CCNP Infrastructure Practice Question
A network engineer is implementing VXLAN in a data center to support a large number of tenants. The engineer must ensure that the VXLAN overlay supports Layer 2 connectivity over a Layer 3 underlay. Which two statements are true about VXLAN? (Choose two.)
⚠ Common exam trap
It's easy for candidates to confuse VXLAN's VNI size with VLAN IDs or assuming multicast is mandatory for VXLAN, when it is only one of several replication methods.
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
✓
VXLAN encapsulates Layer 2 frames in UDP packets for transport over a Layer 3 network.
VXLAN uses a 24-bit VNI, allowing up to 16 million segments, and encapsulates Layer 2 frames in UDP packets for transport over a Layer 3 underlay. These two characteristics enable scalable multi-tenancy and Layer 2 extension across routed networks. The other statements are false: multicast is not mandatory, VTEPs require unique IPs, and VXLAN does not use 12-bit VLAN IDs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
VXLAN encapsulates Layer 2 frames in UDP packets for transport over a Layer 3 network.
Why this is correct
VXLAN encapsulates original Layer 2 frames within UDP packets, typically using UDP port 4789. This encapsulation allows Layer 2 connectivity to be extended over a routed Layer 3 underlay, which is essential for data center interconnect and overlay networks. The use of UDP provides a standard transport that can traverse IP networks.
- ✓
VXLAN uses a 24-bit VNI to identify up to 16 million segments.
Why this is correct
VXLAN uses a 24-bit VXLAN Network Identifier (VNI), which allows for up to 16,777,216 unique segments. This large address space is a key advantage over VLANs, which are limited to 4094 segments. The VNI is carried in the VXLAN header and identifies the overlay network, enabling multi-tenancy at scale.
- ✗
VXLAN uses a 12-bit VLAN ID to identify segments.
Why it's wrong here
VXLAN uses a 24-bit VNI, not a 12-bit VLAN ID. The 12-bit VLAN ID is used in traditional VLANs and is limited to 4094 segments. VXLAN was developed to overcome this limitation, providing a much larger namespace. Thus, this statement is false.
- ✗
VXLAN requires a multicast underlay for all broadcast, unknown unicast, and multicast traffic.
Why it's wrong here
While VXLAN can use multicast for BUM traffic in some designs, it is not a requirement. Modern VXLAN implementations often use head-end replication or multicast with ingress replication. The statement that it requires multicast is false; unicast-based replication is also supported and common in large-scale deployments.
- ✗
VXLAN tunnel endpoints (VTEPs) must be configured with the same IP address on all devices.
Why it's wrong here
Each VTEP must have a unique IP address on the underlay network. The VTEP IP is used as the source and destination for VXLAN tunnels. Having the same IP on multiple devices would cause conflicts and prevent proper tunnel establishment. Therefore, this statement is incorrect.
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.