200-901 Network Fundamentals Practice Question

Which layer of the OSI model uses MAC addresses to deliver frames within the same network segment?

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

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Layer 2 (Data Link)

Layer 2 (Data Link) uses MAC addresses for local delivery.

Answer analysis

For each option: why learners choose it and why it is or isn't the right answer here.

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Layer 2 (Data Link)
Why this is correct
MAC addressing and frame delivery occur at the Data Link layer, which encapsulates packets into frames and uses hardware addresses to forward them between nodes on the same segment. Layer 2 therefore satisfies the stem's requirement for intra-segment delivery, unlike Layer 3's logical IP routing.
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Layer 1 (Physical)
Why it's wrong here
Layer 1 carries raw bits over the medium and has no concept of MAC addresses or frames. It is tempting because MAC addresses are physically burned into network interface hardware, yet frame delivery by MAC occurs at Layer 2, where the correct answer sits.
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Layer 3 (Network)
Why it's wrong here
Layer 3 routes packets between networks using logical IP addresses, not MAC addresses, which stay within one segment. It is tempting because routing ultimately delivers traffic across segments, but intra-segment frame delivery by MAC belongs to Layer 2.
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Layer 4 (Transport)
Why it's wrong here
Layer 4 forwards segments using port numbers for end-to-end transport between hosts, not MAC addresses. It is tempting because Transport layer protocols like TCP do provide reliable delivery, but that reliability operates above the frame-switching function. MAC addressing belongs to Layer 2 (Data Link), which encapsulates packets into frames for delivery within a single network segment.

Quick reference

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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