200-201 Security Monitoring Practice Question
Which OSI layer is responsible for logical addressing and routing?
⚠ Common exam trap
Cisco often tests the distinction between Layer 2 (Data link) and Layer 3 (Network) by having candidates confuse MAC addressing (physical) with IP addressing (logical), leading them to incorrectly select the Data link layer for routing functions.
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
✓
Network layer
The Network layer (Layer 3) is responsible for logical addressing (e.g., IPv4/IPv6 addresses) and routing decisions that determine the best path for data packets across interconnected networks. Protocols such as OSPF, BGP, and ICMP operate at this layer to manage routing tables and forward packets between different subnets or autonomous systems.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Application layer
Why it's wrong here
The Application layer handles user-facing protocols such as HTTP and DNS, providing no logical addressing or path selection. It is tempting because application protocols rely on IP addresses beneath them, but the Network layer alone assigns logical addresses and routes packets between networks.
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Data link layer
Why it's wrong here
The data link layer handles MAC addressing and framing within a single broadcast domain, not logical addressing or path selection between networks. It is tempting because frames carry addresses, but those are physical, and routing between subnets requires the network layer's IP addressing.
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Network layer
Why this is correct
The Network layer (layer 3) handles logical addressing through IP addresses and determines path selection via routing protocols, forwarding packets between networks. Layers 2 and 4 handle physical addressing and transport respectively, so neither performs routing.
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Transport layer
Why it's wrong here
The transport layer provides end-to-end delivery, segmentation and port multiplexing, but carries no logical addressing or routing function. It is tempting because TCP and UDP headers include addresses, yet routers forward on network-layer IP addresses, not transport-layer information.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-201 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 200-201 exam.