- A
Layer 2 – Data Link
Correct. MAC addresses are Layer 2 identifiers.
- B
Layer 1 – Physical
Why wrong: Layer 1 deals with bits and physical media.
- C
Layer 4 – Transport
Why wrong: Layer 4 uses ports and segments.
- D
Layer 3 – Network
Why wrong: Layer 3 uses IP addresses, not MAC addresses.
Question 554 of 1,000
200-901 Network Fundamentals Practice Question
This 200-901 practice question tests your understanding of network fundamentals. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
At which layer of the OSI model do MAC addresses 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 – Data Link
MAC addresses operate at Layer 2 (Data Link) of the OSI model because they are used for local network addressing and frame delivery between directly connected devices. The Data Link layer encapsulates packets into frames and uses MAC addresses to identify source and destination interfaces on the same network segment, as defined by IEEE 802 standards.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 – Data Link
Why this is correct
Correct. MAC addresses are Layer 2 identifiers.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Layer 1 – Physical
Why it's wrong here
Layer 1 deals with bits and physical media.
- ✗
Layer 4 – Transport
Why it's wrong here
Layer 4 uses ports and segments.
- ✗
Layer 3 – Network
Why it's wrong here
Layer 3 uses IP addresses, not MAC addresses.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the confusion between Layer 2 MAC addresses and Layer 3 IP addresses, where candidates mistakenly associate MAC addresses with routing or network-layer functions instead of local data-link delivery.
Detailed technical explanation
How to think about this question
MAC addresses are 48-bit hardware addresses burned into the NIC by the manufacturer, with the first 24 bits representing the OUI (Organizationally Unique Identifier) and the last 24 bits being a unique device identifier. In Ethernet frames, the destination MAC address is used by switches to forward frames based on their MAC address table, and ARP (Address Resolution Protocol) maps Layer 3 IP addresses to Layer 2 MAC addresses for communication on the same subnet.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 200-901 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Quick reference
OSI Model Reference
| Layer | Name | PDU | Key Protocols / Devices |
|---|---|---|---|
| 7 | Application | Data | HTTP, HTTPS, DNS, SMTP, FTP, SSH |
| 6 | Presentation | Data | TLS / SSL, JPEG, ASCII encoding |
| 5 | Session | Data | NetBIOS, RPC, SIP |
| 4 | Transport | Segment / Datagram | TCP, UDP |
| 3 | Network | Packet | IP, ICMP, OSPF — Routers |
| 2 | Data Link | Frame | Ethernet, Wi-Fi, PPP — Switches, Bridges |
| 1 | Physical | Bits | Cables, NICs, Hubs, Repeaters |
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this 200-901 question test?
Network Fundamentals — This question tests Network Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Layer 2 – Data Link — MAC addresses operate at Layer 2 (Data Link) of the OSI model because they are used for local network addressing and frame delivery between directly connected devices. The Data Link layer encapsulates packets into frames and uses MAC addresses to identify source and destination interfaces on the same network segment, as defined by IEEE 802 standards.
What should I do if I get this 200-901 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
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.
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