Showing 11–20 of 100 questions
in OSI Model
An organization implements end-to-end encryption for all data transfers. At which OSI layer is this encryption most commonly implemented?
A
Physical Layer
B
Presentation Layer
C
Session Layer
D
Application Layer
Correct Answer:
B. Presentation Layer
EXPLANATION
While encryption can occur at multiple layers, the Presentation Layer (Layer 6) is traditionally responsible for encryption and decryption of data.
Which of the following statements about the OSI model is correct?
A
All layers must be implemented in hardware
B
Lower layers operate independently of upper layers
C
Each layer provides services to the layer above it
D
The Physical Layer is the most important layer
Correct Answer:
C. Each layer provides services to the layer above it
EXPLANATION
The OSI model is designed such that each layer provides services to the layer above it, following a hierarchical structure.
During network troubleshooting, a frame is found to have an incorrect FCS (Frame Check Sequence). At which layer would this be detected and corrected?
A
Physical Layer
B
Data Link Layer
C
Network Layer
D
Transport Layer
Correct Answer:
B. Data Link Layer
EXPLANATION
FCS is used at the Data Link Layer (Layer 2) to detect errors in frame transmission. Frames with bad FCS are typically discarded.
Which OSI layer is responsible for managing access to the shared physical medium?
A
Physical Layer
B
Data Link Layer
C
Network Layer
D
Transport Layer
Correct Answer:
B. Data Link Layer
EXPLANATION
The Data Link Layer (Layer 2) controls access to the physical medium through MAC addresses and protocols like CSMA/CD.
A technician notices that devices can ping each other but cannot access web services. At which OSI layer might the problem exist?
A
Physical Layer
B
Data Link Layer
C
Application Layer
D
Network Layer
Correct Answer:
C. Application Layer
EXPLANATION
If ping works (Layer 3) but web services don't, the issue is likely at the Application Layer (Layer 7) where HTTP operates.
In the OSI model, what does the Presentation Layer primarily do?
A
Routes data packets
B
Translates, compresses, and encrypts data
C
Manages network addresses
D
Handles error detection
Correct Answer:
B. Translates, compresses, and encrypts data
EXPLANATION
The Presentation Layer (Layer 6) handles data translation, compression, and encryption for proper data representation.
Which protocol operates at the Transport Layer and is connectionless?
A
TCP
B
UDP
C
ICMP
D
IGMP
EXPLANATION
UDP (User Datagram Protocol) is a connectionless protocol at Layer 4 that sends data without establishing a connection.
A network packet is traveling through the internet. At which OSI layer would the packet's source and destination IP addresses be read?
A
Data Link Layer
B
Transport Layer
C
Network Layer
D
Physical Layer
Correct Answer:
C. Network Layer
EXPLANATION
The Network Layer (Layer 3) uses IP addresses to route packets across different networks.
The TCP/IP model has 4 layers, while the OSI model has 7 layers. Which OSI layers are combined into the TCP/IP Application Layer?
A
Layers 5, 6, and 7
B
Layers 4 and 5
C
Layers 3, 4, and 5
D
Layers 6 and 7
Correct Answer:
A. Layers 5, 6, and 7
EXPLANATION
The TCP/IP Application Layer combines the OSI Session Layer (5), Presentation Layer (6), and Application Layer (7).
Which of the following devices operates at Layer 2 of the OSI model?
A
Router
B
Switch
C
Hub
D
Modem
Correct Answer:
B. Switch
EXPLANATION
A switch operates at the Data Link Layer (Layer 2) using MAC addresses to forward frames within the same network segment.
