Q.1 Which layer of the OSI model does the Data Link layer belong to?
Layer 1
Layer 2
Layer 3
Layer 4
Explanation - The Data Link Layer is the second layer in the OSI model, providing node-to-node delivery and framing of data.
Correct answer is: Layer 2
Q.2 What is the main function of the Data Link layer?
Routing
Error detection and correction
Encryption
Application services
Explanation - The Data Link layer is responsible for detecting and sometimes correcting errors that occur in the Physical layer.
Correct answer is: Error detection and correction
Q.3 Which protocol is commonly associated with the Data Link layer?
IP
Ethernet
TCP
HTTP
Explanation - Ethernet is a widely used Data Link layer protocol for LAN communication.
Correct answer is: Ethernet
Q.4 What are the two sublayers of the Data Link layer?
LLC and MAC
IP and TCP
ARP and RARP
UDP and ICMP
Explanation - The Data Link layer is divided into Logical Link Control (LLC) and Media Access Control (MAC) sublayers.
Correct answer is: LLC and MAC
Q.5 Which of the following is NOT a function of the Data Link layer?
Framing
Flow Control
Error Control
Path Selection
Explanation - Path selection is handled by the Network layer, not the Data Link layer.
Correct answer is: Path Selection
Q.6 What does MAC in the Data Link layer stand for?
Media Access Control
Multiple Access Channel
Message Authentication Code
Medium Allocation Control
Explanation - MAC stands for Media Access Control, which manages how devices access the physical medium.
Correct answer is: Media Access Control
Q.7 Which addressing method is used at the Data Link layer?
IP Address
MAC Address
Port Number
Domain Name
Explanation - The Data Link layer uses physical (MAC) addresses to identify devices within the same network.
Correct answer is: MAC Address
Q.8 Which of the following is a Data Link layer device?
Router
Switch
Gateway
Repeater
Explanation - Switches operate at the Data Link layer using MAC addresses to forward frames.
Correct answer is: Switch
Q.9 Which of these is NOT a Data Link layer protocol?
PPP
Ethernet
Frame Relay
ICMP
Explanation - ICMP is a Network layer protocol, while PPP, Ethernet, and Frame Relay are Data Link layer protocols.
Correct answer is: ICMP
Q.10 In HDLC, which type of protocol is used?
Connectionless
Connection-oriented
Hybrid
None
Explanation - HDLC is a connection-oriented protocol ensuring reliable communication at the Data Link layer.
Correct answer is: Connection-oriented
Q.11 What is framing in the Data Link layer?
Breaking messages into packets
Dividing streams into frames
Encrypting data
Assigning IP addresses
Explanation - Framing is the process of dividing the data stream into manageable units called frames.
Correct answer is: Dividing streams into frames
Q.12 What type of errors does the Data Link layer handle?
Transmission errors
Logical errors
Routing errors
Application errors
Explanation - The Data Link layer detects and may correct transmission errors caused by noise and interference.
Correct answer is: Transmission errors
Q.13 Which technique is used for error detection at the Data Link layer?
CRC
AES
SHA
RSA
Explanation - Cyclic Redundancy Check (CRC) is commonly used at the Data Link layer to detect errors in frames.
Correct answer is: CRC
Q.14 What is ARQ in Data Link protocols?
Automatic Repeat Query
Advanced Request Queue
Access Resource Query
Adaptive Routing Quality
Explanation - ARQ is an error control method where retransmissions are requested for corrupted or lost frames.
Correct answer is: Automatic Repeat Query
Q.15 Which Data Link protocol is widely used in DSL Internet connections?
PPP
Ethernet
Frame Relay
ATM
Explanation - Point-to-Point Protocol (PPP) is often used in DSL connections for data encapsulation.
Correct answer is: PPP
Q.16 What does LLC sublayer provide?
Addressing and routing
Error detection and flow control
Medium access scheduling
Encryption
Explanation - The LLC sublayer provides services like error detection, acknowledgments, and flow control.
Correct answer is: Error detection and flow control
Q.17 Which of these uses Data Link layer protocols?
LAN
WAN
Both LAN and WAN
None
Explanation - Data Link layer protocols are used in both LANs (e.g., Ethernet) and WANs (e.g., PPP, Frame Relay).
Correct answer is: Both LAN and WAN
Q.18 Which multiplexing technique can be applied in the Data Link layer?
TDM
FDM
CDM
All of the above
Explanation - Time, Frequency, and Code Division multiplexing can all be used in Data Link layer designs.
Correct answer is: All of the above
Q.19 Which of these is a sliding window protocol?
Stop-and-Wait ARQ
Go-Back-N ARQ
Selective Repeat ARQ
Both Go-Back-N and Selective Repeat
Explanation - Sliding window protocols include Go-Back-N and Selective Repeat for efficient retransmission.
Correct answer is: Both Go-Back-N and Selective Repeat
Q.20 Which of the following is a disadvantage of Stop-and-Wait ARQ?
Simple implementation
High throughput
Low utilization of bandwidth
Error correction
Explanation - Stop-and-Wait ARQ wastes bandwidth since only one frame is sent at a time before acknowledgment.
Correct answer is: Low utilization of bandwidth
Q.21 Which frame field marks the start and end in HDLC?
Flag field
Address field
Control field
Checksum
Explanation - In HDLC, the Flag field (01111110) marks the beginning and end of a frame.
Correct answer is: Flag field
Q.22 Which access control method is used in Ethernet?
ALOHA
CSMA/CD
Polling
Token Passing
Explanation - Ethernet uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD).
Correct answer is: CSMA/CD
Q.23 In Token Ring, what controls access to the medium?
Collision detection
Token passing
Time division
Frequency hopping
Explanation - In Token Ring, a token circulates and grants permission to transmit data.
Correct answer is: Token passing
Q.24 Which of the following is true about Frame Relay?
It is connectionless
It is unreliable
It is fast but offers no error correction
It uses IP addresses
Explanation - Frame Relay provides high-speed transmission but relies on upper layers for error control.
Correct answer is: It is fast but offers no error correction
Q.25 Which Data Link protocol supports both synchronous and asynchronous transmission?
HDLC
Ethernet
PPP
CSMA
Explanation - HDLC supports both synchronous and asynchronous modes of data transmission.
Correct answer is: HDLC