CompTIA Network+ OSI Model and Data Encapsulation Questions and Answers

Question 1

A network technician is troubleshooting an issue where a user can access local network resources but cannot browse the internet.
The technician suspects a router is misconfigured.
At which layer of the OSI model is the technician focusing their troubleshooting efforts?

Accepted Answer

Network Layer

Answer

Transport Layer

Answer

Data Link Layer

Answer

Application Layer

Question 2

During the data encapsulation process, which Protocol Data Unit (PDU) is created at the Transport Layer?

Accepted Answer

Segment

Answer

Frame

Answer

Packet

Answer

Bits

Question 3

A web browser is preparing to send a request for a webpage. It adds an HTTP header to the user's request data. Which of the following OSI model layers is responsible for this initial step?

Accepted Answer

Application Layer

Answer

Presentation Layer

Answer

Session Layer

Answer

Transport Layer

Question 4

Which of the following correctly describes the process of data encapsulation in the OSI model?

Accepted Answer

Each layer adds its own header to the data received from the layer above.

Answer

Each layer adds a trailer to the data as it moves up the stack.

Answer

The Physical Layer converts packets into frames for transmission.

Answer

Each layer removes the header from the previous layer as data moves down the stack.

Question 5

A network switch makes its forwarding decisions based on the MAC address contained within a specific Protocol Data Unit (PDU). What is this PDU called and at which OSI layer does it operate?

Accepted Answer

Frame, at the Data Link Layer

Answer

Packet, at the Network Layer

Answer

Segment, at the Transport Layer

Answer

Bits, at the Physical Layer

Question 6

A network administrator is analyzing a data capture and observes that data is being encrypted and compressed before being sent over the network. Which layer of the OSI model is primarily responsible for these functions?

Accepted Answer

Presentation Layer

Answer

Application Layer

Answer

Session Layer

Answer

Transport Layer