200-901 Network Fundamentals Practice Question
An engineer is troubleshooting a connectivity issue between two devices on different VLANs. The switch connecting the devices is configured with 802.1Q trunking. At which OSI layer do VLANs operate?
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
✓
Layer 2
VLANs operate at Layer 2 (Data Link) because they segment broadcast domains based on MAC addresses and logical grouping, but they do not involve IP routing (Layer 3).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Layer 2
Why this is correct
VLANs are a Layer 2 concept used to separate traffic on a switch.
- ✗
Layer 4
Why it's wrong here
Layer 4 deals with transport protocols like TCP and UDP.
- ✗
Layer 1
Why it's wrong here
Physical layer deals with bits, cables, and signals, not logical segmentation.
- ✗
Layer 3
Why it's wrong here
Layer 3 deals with routing and IP addressing, not VLANs.
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 |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-901 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 200-901 exam.