350-401 Infrastructure Practice Question
A network engineer is implementing VXLAN with a distributed anycast gateway in a Cisco SD-Access fabric. Hosts in the same subnet are attached to different edge nodes. The engineer must ensure that a host retains its default gateway IP and MAC address when it moves between edge nodes. Which technology should be configured on the edge nodes?
⚠ Common exam trap
The trap here is assuming first-hop redundancy protocols like HSRP or VRRP can provide a distributed gateway, when they only offer one active gateway per subnet.
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
✓
Anycast gateway with the same IP and MAC address on all edge nodes for that subnet
A distributed anycast gateway assigns the same virtual IP and virtual MAC to the default gateway on every edge node hosting a subnet. Hosts can move between edge nodes without changing their gateway ARP entry, which preserves connectivity and avoids suboptimal paths. This is a fundamental requirement for seamless host mobility in VXLAN EVPN fabrics.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
VRRP with preemption enabled on all edge nodes
Why it's wrong here
VRRP elects one master and one or more backups, so only one device actively owns the virtual IP and MAC at a time. A host moving to an edge node that is not the master would lose direct gateway access. Preemption does not provide anycast gateway behavior across multiple active nodes.
- ✓
Anycast gateway with the same IP and MAC address on all edge nodes for that subnet
Why this is correct
In a VXLAN fabric, a distributed anycast gateway uses the same virtual IP and virtual MAC for the default gateway on every edge node that hosts the subnet. A roaming host sees no change in gateway identity, so ARP entries remain valid. This provides seamless mobility and optimal forwarding without tromboning traffic to a central gateway.
- ✗
HSRP group with a unique virtual IP per edge node
Why it's wrong here
HSRP provides a single active gateway per subnet, typically on one pair of devices. If a host moves to another edge node, the HSRP virtual IP and MAC may not be present, causing gateway reachability issues. It also does not distribute the gateway across all edge nodes, so it fails the mobility requirement.
- ✗
Proxy ARP on the edge nodes
Why it's wrong here
Proxy ARP allows a router to answer ARP requests for hosts on other subnets, but it does not provide a consistent default gateway identity. When a host moves, its ARP cache may still point to the old gateway MAC, causing black holes. Proxy ARP is not a mobility solution for distributed gateways.
Visual reference
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
Network Access Control and AAA
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
Cisco SD-Access
Cisco Software-Defined Access is a network architecture that uses a central controller to automate and secure user and device access across an enterprise network.
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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.