Computer Networks Questions & Answers – Data Link
Layer
1. The data link layer takes the
packets from _________ and encapsulates them into frames for transmission.
a) network layer
b) physical layer
c) transport layer
d) application layer
a) network layer
b) physical layer
c) transport layer
d) application layer
Answer: a
Explanation: In computer networks, the data from application layer is sent to transport layer and is converted to segments. These segments are then transferred to the network layer and these are called packets. These packets are then sent to data link layer where they are encapsulated into frames. These frames are then transferred to physical layer where the frames are converted to bits.
Explanation: In computer networks, the data from application layer is sent to transport layer and is converted to segments. These segments are then transferred to the network layer and these are called packets. These packets are then sent to data link layer where they are encapsulated into frames. These frames are then transferred to physical layer where the frames are converted to bits.
2. Which one of the following task
is not done by data link layer?
a) framing
b) error control
c) flow control
d) channel coding
a) framing
b) error control
c) flow control
d) channel coding
Answer: d
Explanation: Channel coding is the function of physical layer. Data link layer mainly deals with framing, error control and flow control.
Explanation: Channel coding is the function of physical layer. Data link layer mainly deals with framing, error control and flow control.
3. Which sublayer of the data link
layer performs data link functions that depend upon the type of medium?
a) logical link control sublayer
b) media access control sublayer
c) network interface control sublayer
d) none of the mentioned
a) logical link control sublayer
b) media access control sublayer
c) network interface control sublayer
d) none of the mentioned
Answer: b
Explanation: Media access control (MAC) deals with transmission of data packets to and from the network-interface card, and also to and from another remotely shared channel.
Explanation: Media access control (MAC) deals with transmission of data packets to and from the network-interface card, and also to and from another remotely shared channel.
4. Header of a frame generally
contains
a) synchronization bytes
b) addresses
c) frame identifier
d) all of the mentioned
a) synchronization bytes
b) addresses
c) frame identifier
d) all of the mentioned
Answer: d
Explanation: In computer networks, the header is a part of the data that contains all the required information about the transmission of the file. It contains information like synchronization bytes, addresses, frame identifier etc.
Explanation: In computer networks, the header is a part of the data that contains all the required information about the transmission of the file. It contains information like synchronization bytes, addresses, frame identifier etc.
5. Automatic repeat request error
management mechanism is provided by
a) logical link control sublayer
b) media access control sublayer
c) network interface control sublayer
d) none of the mentioned
a) logical link control sublayer
b) media access control sublayer
c) network interface control sublayer
d) none of the mentioned
Answer: a
Explanation: The logical link control is a sublayer of data link layer whose main function is to manage traffic, flow and error control. This layer also acts as an interface between MAC layer and network layer.
Explanation: The logical link control is a sublayer of data link layer whose main function is to manage traffic, flow and error control. This layer also acts as an interface between MAC layer and network layer.
6. When 2 or more bits in a data
unit has been changed during the transmission, the error is called
a) random error
b) burst error
c) inverted error
d) none of the mentioned
a) random error
b) burst error
c) inverted error
d) none of the mentioned
Answer: b
Explanation: When a single bit error occurs in a data, it is called single bit error. When more than a single bit of data is corrupted or has error, it is called burst error.
Explanation: When a single bit error occurs in a data, it is called single bit error. When more than a single bit of data is corrupted or has error, it is called burst error.
7. CRC stands for
a) cyclic redundancy check
b) code repeat check
c) code redundancy check
d) cyclic repeat check
a) cyclic redundancy check
b) code repeat check
c) code redundancy check
d) cyclic repeat check
Answer: a
Explanation: Cyclic redundancy check is a code that is added to a data which helps us to identify any error that occurred during the transmission of the data.
Explanation: Cyclic redundancy check is a code that is added to a data which helps us to identify any error that occurred during the transmission of the data.
8. Which one of the following is a
data link protocol?
a) ethernet
b) point to point protocol
c) hdlc
d) all of the mentioned
a) ethernet
b) point to point protocol
c) hdlc
d) all of the mentioned
Answer: d
Explanation: There are many data link layer protocols. Some of them are SDLC (synchronous data link protocol), HDLC (High level data link control), SLIP (serial line interface protocol), PPP (Point to point protocol) etc.
Explanation: There are many data link layer protocols. Some of them are SDLC (synchronous data link protocol), HDLC (High level data link control), SLIP (serial line interface protocol), PPP (Point to point protocol) etc.
9. Which one of the following is the
multiple access protocol for channel access control?
a) CSMA/CD
b) CSMA/CA
c) Both CSMA/CD & CSMA/CA
d) None of the mentioned
a) CSMA/CD
b) CSMA/CA
c) Both CSMA/CD & CSMA/CA
d) None of the mentioned
Answer: c
Explanation: In CSMA/CD, it deals with detection of collision after collision has occurred. Whereas CSMA/CA deals with preventing collision. CSMA/CD is abbreviation for Carrier Sensing Multiple Access/Collision detection. CSMA/CA is abbreviation for Carrier Sensing Multiple Access/Collision Avoidance.
Explanation: In CSMA/CD, it deals with detection of collision after collision has occurred. Whereas CSMA/CA deals with preventing collision. CSMA/CD is abbreviation for Carrier Sensing Multiple Access/Collision detection. CSMA/CA is abbreviation for Carrier Sensing Multiple Access/Collision Avoidance.
10. The technique of temporarily
delaying outgoing acknowledgements so that they can be hooked onto the next
outgoing data frame is called
a) piggybacking
b) cyclic redundancy check
c) fletcher’s checksum
d) none of the mentioned
a) piggybacking
b) cyclic redundancy check
c) fletcher’s checksum
d) none of the mentioned
Answer: a
Explanation: Piggybacking is a technique in which the acknowledgment is temporarily delayed so as to be hooked with the next outgoing data frame.
Explanation: Piggybacking is a technique in which the acknowledgment is temporarily delayed so as to be hooked with the next outgoing data frame.
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