200-901 Network Fundamentals Practice Question
An engineer is troubleshooting a network issue and needs to verify the MAC address of the next-hop router on a directly connected segment. Which layer of the OSI model does the engineer need to examine to find this information?
⚠ Common exam trap
Cisco often tests the misconception that MAC addresses belong to the Network layer because they are used in routing decisions, but the trap is that MAC addresses are strictly a Data Link layer construct used for local segment delivery, not for end-to-end path determination.
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
✓
Data Link layer (Layer 2)
The MAC address of the next-hop router is found in the Data Link layer (Layer 2) header of a frame. When a device sends an IP packet to a next-hop router on the same segment, it encapsulates the packet in a frame with the destination MAC address of that router's interface. To verify this address, you examine Layer 2 information, such as by using the `show arp` command on Cisco devices to view the MAC-to-IP mapping.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Data Link layer (Layer 2)
Why this is correct
MAC addresses are used at Layer 2 for local network communication.
- ✗
Transport layer (Layer 4)
Why it's wrong here
Layer 4 deals with TCP/UDP segments and ports.
- ✗
Physical layer (Layer 1)
Why it's wrong here
Layer 1 deals with bits, cables, and hubs, not MAC addresses.
- ✗
Network layer (Layer 3)
Why it's wrong here
Layer 3 uses IP addresses, not MAC addresses.
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
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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.