🏠 Home > Data Communication & Networks > 9. Introduction to Data Link Layer > Two Sublayers in Data Link Layer
← Back to 9. Introduction to Data Link Layer

📝 Two Sublayers in Data Link Layer

📖 From Data Communication & Networks • 9. Introduction to Data Link Layer • 8 questions available

Practice MCQs for Two Sublayers in Data Link Layer. Test your knowledge with carefully crafted questions across easy, medium, and hard difficulty levels.

🔄 Last updated: 2026-07-31

3
Easy Questions
3
Medium Questions
2
Hard Questions

📝 Sample Questions

Q1. What is the primary function of the data-link sublayer in a router?

🔹 A. To route packets between different autonomous systems
🔹 B. To encapsulate network-layer packets into frames for transmission on the local link
🔹 C. To encrypt data for secure transport
🔹 D. To assign IP addresses to hosts

💡 Difficulty: easy | ✅ Correct: B

Q2. Given that each router uses two data-link layers, what can be inferred about the role of MAC addresses when a frame traverses router R5?

🔹 A. The source MAC becomes the destination MAC on the outbound interface
🔹 B. The original source MAC is retained throughout the entire path
🔹 C. A new source MAC is inserted for the outbound link, while the destination MAC is set to the next hop’s MAC
🔹 D. MAC addresses are irrelevant at the router level

💡 Difficulty: medium | ✅ Correct: C

Q3. If a router mistakenly copies the source MAC address from the incoming frame into the destination MAC field of the outgoing frame, which network‑level consequence is most likely?

🔹 A. The frame will be delivered to the original sender, causing a loop
🔹 B. The frame will be discarded by the next‑hop device due to MAC mismatch
🔹 C. The frame will be broadcast to all hosts on the segment
🔹 D. The frame will reach the correct destination but with corrupted payload

💡 Difficulty: hard | ✅ Correct: B

⬆️ View all questions in the quiz below

🔗 Related Topics

📝 Data Link Layer basics📝 Nodes and Links in Data Link Layer📝 Services in Data Link Layer📝 Two Categories of Links in Data Link Layer📝 Link Layer Addressing in Data Link Layer
🚀 Start Quiz 📝 Practice Mode