Q1. Which of the following terms refers to the OSI Network Layer?
- A.Layer 2
- B.Layer 5
- C.Layer 3✓ Correct
- D.Layer 4
Explanation: Layer 3 of the OSI model is the Network Layer, responsible for logical addressing and routing.
CompTIA Network+ OSI Model Practice Questions: OSI Layers
29 free, exam-style CompTIA Network+ OSI Model (N10-009) practice questions covering OSI Layers. Each question shows the correct answer and a clear explanation. Ready for the real thing? Take the full timed quiz below.
Q2. The term "Presentation Layer" is used in reference to:
- A.Layer 7 of the OSI model
- B.Layer 6 of the OSI model✓ Correct
- C.Layer 6 of the OSI model
- D.Layer 4 of the OSI model
Explanation: The Presentation Layer is Layer 6 of the OSI model, handling data translation, encryption, and compression.
Q3. Which OSI layer assumes the responsibility for opening, closing, and maintaining connections between applications?
- A.Network Layer
- B.Data Link Layer
- C.Application Layer
- D.Session Layer✓ Correct
Explanation: The Session Layer (Layer 5) manages sessions between applications, including opening, closing, and maintaining connections.
Q4. In the OSI model, the Data Link Layer is also known as:
- A.Layer 3
- B.Layer 1
- C.Layer 5
- D.Layer 2✓ Correct
Explanation: The Data Link Layer is Layer 2 of the OSI model.
Q5. Layer 2 of the OSI model is also referred to as:
- A.Transport Layer
- B.Network Layer
- C.Data Link Layer✓ Correct
- D.Physical Layer
Explanation: Layer 2 is the Data Link Layer.
Q6. Data format translation, data compression, and data encryption/decryption take place at the:
- A.Application Layer of the OSI model
- B.Presentation Layer of the OSI model✓ Correct
- C.Session Layer of the OSI model
- D.Transport Layer of the OSI model
Explanation: These functions (formatting, compression, encryption) are primary responsibilities of the Presentation Layer (Layer 6).
Q7. Which of the following answers refers to Layer 1 of the OSI model?
- A.Transport Layer
- B.Physical Layer✓ Correct
- C.Application Layer
- D.Data Link Layer
Explanation: Layer 1 is the Physical Layer.
Q8. The term "Application Layer" is used in reference to:
- A.Layer 6 of the OSI model
- B.Layer 4 of the OSI model
- C.Layer 7 of the OSI model✓ Correct
- D.Layer 5 of the OSI model
Explanation: The Application Layer is Layer 7, the topmost layer of the OSI model.
Q9. Which of the OSI layers listed below is also known as the Session Layer?
- A.Layer 6
- B.Layer 3
- C.Layer 5✓ Correct
- D.Layer 2
Explanation: Layer 5 is the Session Layer.
Q10. Which OSI layer enables direct interaction between the end-user and the network?
- A.Layer 5
- B.Layer 1
- C.Layer 7✓ Correct
- D.Layer 3
Explanation: Layer 7 (Application Layer) is closest to the end user and interacts directly with software applications.
Q11. Which of the following answers refers to Layer 6 of the OSI model?
- A.Data Link Layer
- B.Application Layer
- C.Presentation Layer✓ Correct
- D.Session Layer
Explanation: Layer 6 is the Presentation Layer.
Q12. Which of the answers listed below refers to the Physical Layer of the OSI model?
- A.Layer 2
- B.Layer 7
- C.Layer 1✓ Correct
- D.Layer 4
Explanation: Layer 1 is the Physical Layer.
Q13. Layer 7 of the OSI model is also known as:
- A.Transport Layer
- B.Presentation Layer
- C.Session Layer
- D.Application Layer✓ Correct
Explanation: Layer 7 is the Application Layer.
Q14. Which of the following answers refers to Layer 5 of the OSI model?
- A.Session Layer✓ Correct
- B.Application Layer
- C.Transport Layer
- D.Presentation Layer
Explanation: Layer 5 is the Session Layer.
Q15. What is the name of Layer 3 in the OSI model?
- A.Network Layer✓ Correct
- B.Data Link Layer
- C.Session Layer
- D.Transport Layer
Explanation: Layer 3 is the Network Layer.
Q16. Which of the answers listed below refers to Layer 4 of the OSI model?
- A.Network Layer
- B.Data Link Layer
- C.Session Layer
- D.Transport Layer✓ Correct
Explanation: Layer 4 is the Transport Layer.
Q17. Which OSI layer is responsible for HTTP and DNS application services?
- A.Layer 7✓ Correct
- B.Layer 6
- C.Layer 4
- D.Layer 2
Explanation: The Application layer provides network services directly to user applications and application protocols.
Q18. Which OSI layer is associated with encryption, compression, and data format translation?
- A.Presentation layer✓ Correct
- B.Session layer
- C.Transport layer
- D.Physical layer
Explanation: Layer 6, the Presentation layer, handles data representation tasks such as encryption and formatting.
Q19. Which OSI layer establishes, manages, and tears down communication sessions?
- A.Session layer✓ Correct
- B.Network layer
- C.Data Link layer
- D.Physical layer
Explanation: Layer 5 manages sessions between applications or hosts.
Q20. Which OSI layer defines cables, connectors, signaling, and radio transmission?
- A.Physical layer✓ Correct
- B.Transport layer
- C.Session layer
- D.Application layer
Explanation: The Physical layer defines media, signaling, pinouts, and transmission characteristics.
Q21. Which layer is most associated with SSL/TLS encryption in the OSI model?
- A.Presentation layer✓ Correct
- B.Network layer
- C.Physical layer
- D.Data Link layer
Explanation: TLS is often mapped to the Presentation layer because it provides encryption and data representation services.
Q22. Which OSI layer is closest to the end user?
- A.Application layer✓ Correct
- B.Network layer
- C.Data Link layer
- D.Physical layer
Explanation: The Application layer is the top OSI layer and interfaces with application services.
Q23. Which OSI layer is closest to the network medium?
- A.Physical layer✓ Correct
- B.Session layer
- C.Presentation layer
- D.Application layer
Explanation: The Physical layer is closest to the cabling, fiber, or wireless medium.
Q24. Which OSI layer is most directly associated with Ethernet switches learning source addresses?
- A.Data Link layer✓ Correct
- B.Network layer
- C.Session layer
- D.Presentation layer
Explanation: Switches learn source MAC addresses from Layer 2 Ethernet frames.
Q25. Which OSI layer is most associated with JPEG, ASCII, and data representation examples?
- A.Presentation layer✓ Correct
- B.Transport layer
- C.Network layer
- D.Data Link layer
Explanation: The Presentation layer handles data formats and representation.
Q26. Which OSI layer is most associated with RPC session setup examples?
- A.Session layer✓ Correct
- B.Physical layer
- C.Data Link layer
- D.Network layer
Explanation: The Session layer is commonly associated with establishing and managing sessions such as RPC communication.
Q27. Which OSI layer would a web proxy primarily inspect for HTTP headers and URLs?
- A.Application layer✓ Correct
- B.Physical layer
- C.Data Link layer
- D.Network layer only
Explanation: HTTP headers and URLs are application-layer information.
Q28. Which OSI layer provides logical end-to-end conversations between applications?
- A.Transport layer✓ Correct
- B.Physical layer
- C.Data Link layer
- D.Presentation layer only
Explanation: The Transport layer provides end-to-end communication services such as TCP sessions and UDP datagrams.
Q29. Which OSI layer is responsible for converting frames into electrical, optical, or radio signals?
- A.Physical layer✓ Correct
- B.Data Link layer
- C.Network layer
- D.Application layer
Explanation: The Physical layer transmits bits over the physical medium as signals.