ISC2 CC Network Security Practice Question
Which OSI layer is responsible for routing packets across networks using IP addresses?
⚠ Common exam trap
A common pitfall is confusing the Data Link layer's local delivery role (Layer 2) with the Network layer's internetwork routing function (Layer 3). Remember that routing across networks using IP addresses occurs at Layer 3.
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. It uses IP addresses to determine the best path for packets to travel from source to destination across different networks. Protocols like IP (IPv4/IPv6), OSPF, and BGP operate at this layer to perform routing decisions.
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
Deals with bits and physical media, not addressing.
- ✓
Layer 3 - Network
Why this is correct
Correct. Routing and IP addressing occur at Layer 3.
- ✗
Layer 4 - Transport
Why it's wrong here
Handles TCP/UDP segments and reliability, not routing.
- ✗
Layer 2 - Data Link
Why it's wrong here
Uses MAC addresses and switches, not IP routing.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CC practice question is part of Courseiva's free ISC2 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 CC exam.