350-401 Infrastructure Practice Question
An engineer is implementing a VXLAN overlay network using Cisco Nexus switches. The engineer needs to ensure that the VXLAN tunnel endpoint (VTEP) can dynamically learn the mapping of remote VTEP IP addresses to MAC addresses. Which protocol should be used to achieve this dynamic learning?
⚠ Common exam trap
Many exam-takers confuse underlay routing protocols like OSPF or IS-IS with overlay control plane protocols, which are responsible for MAC address learning in VXLAN EVPN.
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
✓
MP-BGP EVPN
MP-BGP EVPN is the control plane protocol used in VXLAN overlays to dynamically exchange MAC address and IP address reachability information between VTEPs. It replaces flood-and-learn with a scalable, efficient control plane, enabling optimal forwarding and reducing flooding. This is the correct protocol for dynamic VTEP mapping learning.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
OSPF
Why it's wrong here
OSPF is a routing protocol used for underlay networks or within the tenant network, but it does not provide a mechanism for VTEPs to exchange MAC address mappings. OSPF operates at Layer 3 and does not carry MAC address information. Therefore, it cannot be used for dynamic learning of remote VTEP IP-to-MAC mappings in a VXLAN overlay.
- ✗
IS-IS
Why it's wrong here
IS-IS is a link-state routing protocol similar to OSPF, used for underlay routing. Like OSPF, it does not support the exchange of MAC address reachability information required for VXLAN overlay. It cannot dynamically learn remote VTEP mappings. Thus, IS-IS is not suitable for this purpose.
- ✓
MP-BGP EVPN
Why this is correct
MP-BGP EVPN is a control plane protocol that allows VTEPs to exchange MAC address and IP address reachability information. It provides a scalable way to dynamically learn remote VTEP mappings, eliminating the need for flood-and-learn. In a VXLAN EVPN setup, MP-BGP EVPN is used to distribute MAC/IP bindings, enabling efficient and scalable overlay networks. This is the correct protocol for dynamic learning.
- ✗
PIM sparse mode
Why it's wrong here
PIM sparse mode is a multicast routing protocol used for underlay multicast transport in VXLAN flood-and-learn deployments. It does not provide a control plane for MAC address learning. While it can be used to transport broadcast, unknown unicast, and multicast traffic, it does not enable dynamic VTEP mapping learning. Therefore, it is incorrect.
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
Go deeper
Related to this question
Learn chapter
VLANs and Spanning Tree Protocol Concepts
Key term
Fabric Fundamentals
Fabric Fundamentals is the set of core concepts behind a network fabric, where switches and routers form a single logical system that simplifies traffic forwarding and automation.
Key term
VXLAN
VXLAN is a network overlay technology that encapsulates Layer 2 Ethernet frames in UDP packets to extend VLANs across Layer 3 networks.
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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.