ICT Networking Models and Protocols 2 — Questions and Answers
Question 1: Which OSI layer is responsible for establishing, maintaining, and terminating communication sessions between applications?
- Transport layer
- Session layer (Correct answer)
- Presentation layer
- Application layer
Correct answer: Session layer
The Session layer (Layer 5) manages dialog control and synchronization between communicating systems.
Question 2: In the TCP/IP model, which layer corresponds most closely to both the OSI Session and Presentation layers?
- Network Access layer
- Internet layer
- Transport layer
- Application layer (Correct answer)
Correct answer: Application layer
The TCP/IP Application layer combines the functions of the OSI Application, Presentation, and Session layers.
Question 3: What is the primary purpose of the Presentation layer in the OSI model?
- Routing packets between networks
- Data encryption, compression, and format translation (Correct answer)
- Error detection and retransmission
- Physical signal transmission
Correct answer: Data encryption, compression, and format translation
The Presentation layer (Layer 6) handles data formatting, encryption, and compression so the Application layer can interpret the data.
Question 4: Which protocol operates at the OSI Network layer and is responsible for logical addressing and routing?
- Ethernet
- IP (Correct answer)
- TCP
- HTTP
Correct answer: IP
IP (Internet Protocol) operates at Layer 3 and handles logical (IP) addressing and routing of packets.
Question 5: A network technician needs to capture and analyze packets on a network segment. Which OSI layer do packet sniffers primarily operate at?
- Layer 7 – Application
- Layer 4 – Transport
- Layer 2 – Data Link (Correct answer)
- Layer 1 – Physical
Correct answer: Layer 2 – Data Link
Packet sniffers capture frames at the Data Link layer (Layer 2), though they can decode information from all encapsulated layers.
Question 6: Which of the following best describes the concept of 'encapsulation' in networking?
- Encrypting data before transmission
- Adding headers and trailers as data moves down the OSI layers (Correct answer)
- Compressing data to reduce bandwidth usage
- Converting analog signals to digital
Correct answer: Adding headers and trailers as data moves down the OSI layers
Encapsulation is the process of adding protocol-specific headers (and sometimes trailers) at each OSI layer as data moves from sender to receiver.
Question 7: UDP differs from TCP primarily because UDP:
- Guarantees packet delivery with acknowledgments
- Is connection-oriented and uses a three-way handshake
- Is connectionless and does not guarantee delivery (Correct answer)
- Operates at the Network layer
Correct answer: Is connectionless and does not guarantee delivery
UDP is a connectionless Transport layer protocol that sends datagrams without establishing a connection or guaranteeing delivery.
ICT Networking Models and Protocols 2
Which OSI layer is responsible for establishing, maintaining, and terminating communication sessions between applications?