CompTIA Network+ Network+ OSI Model Layers and Functions 3

Question 1

Which OSI layer PDU (Protocol Data Unit) is called a 'segment'?

Accepted Answer

Transport layer

Answer

The Transport layer's PDU is called a segment, which contains port numbers and sequencing information.

Question 2

A network engineer is troubleshooting a connectivity issue and wants to verify physical signal integrity on the cable. Which OSI layer should they focus on?

Accepted Answer

Layer 1

Answer

The Physical layer (Layer 1) deals with the transmission of raw bits over a physical medium, including signal integrity.

Question 3

Which protocol at the Application layer is used to translate domain names to IP addresses?

Accepted Answer

DNS

Answer

DNS (Domain Name System) operates at the Application layer and resolves human-readable domain names to IP addresses.

Question 4

During data transmission, which OSI layer adds a trailer containing a Frame Check Sequence (FCS) for error detection?

Accepted Answer

Data Link layer

Answer

The Data Link layer adds both a header and a trailer; the trailer contains the FCS used for error detection.

Question 5

A VPN concentrator terminates encrypted tunnels at which OSI layer when using IPSec in tunnel mode?

Accepted Answer

Layer 3

Answer

IPSec in tunnel mode operates at the Network layer (Layer 3), encrypting entire IP packets and encapsulating them in new IP packets.

CompTIA Practice Test

CompTIA Practice Test

CompTIA Network+ Network+ OSI Model Layers and Functions 3