200-901 Network Fundamentals Practice Question
Which OSI layer is responsible for routing packets across different networks?
⚠ Common exam trap
Cisco often tests the distinction between Layer 2 switching (MAC-based, same network) and Layer 3 routing (IP-based, between networks), and the trap here is confusing the Data Link layer's local forwarding with the Network layer's internetwork routing.
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 3 (Network)
The Network layer (Layer 3) is responsible for logical addressing and routing packets between different networks. Protocols like IP (IPv4/IPv6) use routing tables and algorithms (e.g., OSPF, BGP) to determine the best path for forwarding packets across multiple hops. Without Layer 3, traffic could not leave a local broadcast domain.
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 1 (Physical)
Why it's wrong here
Layer 1 deals with raw bit transmission over physical media.
- ✓
Layer 3 (Network)
Why this is correct
Layer 3 uses IP addresses to route packets across networks.
- ✗
Layer 4 (Transport)
Why it's wrong here
Layer 4 provides end-to-end communication and reliability.
- ✗
Layer 2 (Data Link)
Why it's wrong here
Layer 2 handles frame switching within the same network segment.
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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.