350-401 Infrastructure Practice Question
A network engineer is deploying a new branch office that uses a single switch stack with two member switches. The stack must forward traffic between access ports in different VLANs without involving an external router. Which feature should be configured to meet this requirement?
⚠ Common exam trap
The trap here is assuming that creating VLANs alone enables communication between them, when in fact Layer 3 routing must be explicitly enabled with SVIs.
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
✓
Configure an SVI for each VLAN on the switch stack and enable IP routing with the ip routing command.
The requirement is to route traffic between VLANs using the switch stack itself. Creating switched virtual interfaces for each VLAN and enabling IP routing allows the stack to perform inter-VLAN routing without an external router. This is a standard design for collapsed core or branch offices where a multilayer switch provides both Layer 2 and Layer 3 forwarding.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Configure private VLANs on the access ports to allow communication between VLANs.
Why it's wrong here
Private VLANs restrict Layer 2 connectivity within a primary VLAN by isolating ports; they do not route traffic between different VLANs. In fact, they are used to prevent hosts on the same subnet from communicating directly. This would not allow inter-VLAN traffic and is unrelated to the requirement.
- ✓
Configure an SVI for each VLAN on the switch stack and enable IP routing with the ip routing command.
Why this is correct
This is correct because an SVI provides Layer 3 processing for a VLAN, and enabling IP routing on the stack allows inter-VLAN traffic to be routed internally. The stack acts as a single logical switch, so SVIs are active on the stack master and traffic between VLANs is routed without an external router.
- ✗
Configure VTP transparent mode on all switches and create the VLANs manually.
Why it's wrong here
VTP transparent mode only affects VLAN database propagation; it does not provide Layer 3 forwarding between VLANs. Even with VLANs created, the stack would still need a routing function such as SVIs or an external router to pass traffic between subnets. This option does not achieve the requirement.
- ✗
Configure 802.1Q trunk links between the two stack members and enable dynamic ARP inspection.
Why it's wrong here
Stack members are already connected via stacking cables and operate as a single logical switch; 802.1Q trunks between them are unnecessary. Dynamic ARP inspection is a security feature that validates ARP packets and does not perform routing. Neither feature enables inter-VLAN forwarding.
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Learn chapter
Network Access Control and AAA
Key term
Switch Virtual Interface
A logical interface on a network switch that allows it to be managed and communicate with other devices using IP addresses.
Key term
Two-Tier vs Three-Tier Architecture
Two-Tier and Three-Tier Architecture are network design models that separate network functions into layers to improve performance, security, and manageability, with the two-tier model having a collapsed core and distribution layer, and the three-tier model adding a separate core layer.
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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.