CN · Data Link & Errors interview questions

36 real CN · Data Link & Errors questions from the Computer Science Fundamentals bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.

1. What is framing?

Junior
  1. A.the number of differing bit positions between two codewords, determining error detection and correction power
  2. B.a wireless access method that avoids collisions by waiting and signaling intent before transmitting, used by Wi-Fi
  3. C.a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
  4. D.grouping a stream of bits into discrete frames with clear start and end delimiters
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3. Which statement is correct?

Junior
  1. A.framing — attaching an acknowledgement onto an outgoing data frame to save a separate control frame
  2. B.framing — a globally unique 48-bit hardware identifier burned into a network interface card
  3. C.framing — grouping a stream of bits into discrete frames with clear start and end delimiters
  4. D.framing — a wireless access method that avoids collisions by waiting and signaling intent before transmitting, used by Wi-Fi
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4. What is MAC address?

Junior
  1. A.the number of differing bit positions between two codewords, determining error detection and correction power
  2. B.an error-detection code using polynomial division that catches burst errors better than a checksum
  3. C.a globally unique 48-bit hardware identifier burned into a network interface card
  4. D.a reliability scheme sending one frame and waiting for its acknowledgement before sending the next
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6. Which statement is correct?

Junior
  1. A.MAC address — a globally unique 48-bit hardware identifier burned into a network interface card
  2. B.MAC address — a reliability scheme allowing several outstanding frames to improve throughput over stop-and-wait
  3. C.MAC address — an error-correcting code that inserts parity bits at power-of-two positions to locate and fix a single-bit error
  4. D.MAC address — an error-detection code using polynomial division that catches burst errors better than a checksum
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7. What is parity bit?

Junior
  1. A.a single appended bit making the count of ones even or odd to detect single-bit errors
  2. B.an error-correcting code that inserts parity bits at power-of-two positions to locate and fix a single-bit error
  3. C.the number of differing bit positions between two codewords, determining error detection and correction power
  4. D.a globally unique 48-bit hardware identifier burned into a network interface card
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9. Which statement is correct?

Junior
  1. A.parity bit — a reliability scheme allowing several outstanding frames to improve throughput over stop-and-wait
  2. B.parity bit — a single appended bit making the count of ones even or odd to detect single-bit errors
  3. C.parity bit — a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
  4. D.parity bit — attaching an acknowledgement onto an outgoing data frame to save a separate control frame
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10. What is checksum?

Junior
  1. A.attaching an acknowledgement onto an outgoing data frame to save a separate control frame
  2. B.a reliability scheme sending one frame and waiting for its acknowledgement before sending the next
  3. C.the number of differing bit positions between two codewords, determining error detection and correction power
  4. D.a summed value of a data block sent alongside it so the receiver can detect corruption
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12. Which statement is correct?

Junior
  1. A.checksum — a single appended bit making the count of ones even or odd to detect single-bit errors
  2. B.checksum — a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
  3. C.checksum — an error-detection code using polynomial division that catches burst errors better than a checksum
  4. D.checksum — a summed value of a data block sent alongside it so the receiver can detect corruption
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13. What is CSMA/CD?

Mid
  1. A.an error-detection code using polynomial division that catches burst errors better than a checksum
  2. B.a single appended bit making the count of ones even or odd to detect single-bit errors
  3. C.the number of differing bit positions between two codewords, determining error detection and correction power
  4. D.a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
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15. Which statement is correct?

Mid
  1. A.CSMA/CD — a reliability scheme sending one frame and waiting for its acknowledgement before sending the next
  2. B.CSMA/CD — grouping a stream of bits into discrete frames with clear start and end delimiters
  3. C.CSMA/CD — a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
  4. D.CSMA/CD — a reliability scheme allowing several outstanding frames to improve throughput over stop-and-wait
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16. What is CSMA/CA?

Mid
  1. A.a reliability scheme sending one frame and waiting for its acknowledgement before sending the next
  2. B.a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
  3. C.a wireless access method that avoids collisions by waiting and signaling intent before transmitting, used by Wi-Fi
  4. D.a single appended bit making the count of ones even or odd to detect single-bit errors
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18. Which statement is correct?

Mid
  1. A.CSMA/CA — a globally unique 48-bit hardware identifier burned into a network interface card
  2. B.CSMA/CA — an error-detection code using polynomial division that catches burst errors better than a checksum
  3. C.CSMA/CA — a wireless access method that avoids collisions by waiting and signaling intent before transmitting, used by Wi-Fi
  4. D.CSMA/CA — attaching an acknowledgement onto an outgoing data frame to save a separate control frame
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19. What is cyclic redundancy check (CRC)?

Mid
  1. A.a single appended bit making the count of ones even or odd to detect single-bit errors
  2. B.an error-detection code using polynomial division that catches burst errors better than a checksum
  3. C.a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
  4. D.a globally unique 48-bit hardware identifier burned into a network interface card
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21. Which statement is correct?

Mid
  1. A.cyclic redundancy check (CRC) — an error-detection code using polynomial division that catches burst errors better than a checksum
  2. B.cyclic redundancy check (CRC) — the number of differing bit positions between two codewords, determining error detection and correction power
  3. C.cyclic redundancy check (CRC) — an error-correcting code that inserts parity bits at power-of-two positions to locate and fix a single-bit error
  4. D.cyclic redundancy check (CRC) — grouping a stream of bits into discrete frames with clear start and end delimiters
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22. What is stop-and-wait ARQ?

Mid
  1. A.grouping a stream of bits into discrete frames with clear start and end delimiters
  2. B.a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
  3. C.the number of differing bit positions between two codewords, determining error detection and correction power
  4. D.a reliability scheme sending one frame and waiting for its acknowledgement before sending the next
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24. Which statement is correct?

Mid
  1. A.stop-and-wait ARQ — a reliability scheme allowing several outstanding frames to improve throughput over stop-and-wait
  2. B.stop-and-wait ARQ — a reliability scheme sending one frame and waiting for its acknowledgement before sending the next
  3. C.stop-and-wait ARQ — an error-detection code using polynomial division that catches burst errors better than a checksum
  4. D.stop-and-wait ARQ — a single appended bit making the count of ones even or odd to detect single-bit errors
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25. What is sliding window ARQ?

Mid
  1. A.an error-detection code using polynomial division that catches burst errors better than a checksum
  2. B.a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
  3. C.a reliability scheme allowing several outstanding frames to improve throughput over stop-and-wait
  4. D.a reliability scheme sending one frame and waiting for its acknowledgement before sending the next
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27. Which statement is correct?

Mid
  1. A.sliding window ARQ — the number of differing bit positions between two codewords, determining error detection and correction power
  2. B.sliding window ARQ — grouping a stream of bits into discrete frames with clear start and end delimiters
  3. C.sliding window ARQ — a reliability scheme allowing several outstanding frames to improve throughput over stop-and-wait
  4. D.sliding window ARQ — a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
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28. What is Hamming distance?

Senior
  1. A.the number of differing bit positions between two codewords, determining error detection and correction power
  2. B.a wired access method where stations listen, transmit, detect collisions, and back off, used by classic Ethernet
  3. C.a reliability scheme sending one frame and waiting for its acknowledgement before sending the next
  4. D.a summed value of a data block sent alongside it so the receiver can detect corruption
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30. Which statement is correct?

Senior
  1. A.Hamming distance — a single appended bit making the count of ones even or odd to detect single-bit errors
  2. B.Hamming distance — the number of differing bit positions between two codewords, determining error detection and correction power
  3. C.Hamming distance — grouping a stream of bits into discrete frames with clear start and end delimiters
  4. D.Hamming distance — a globally unique 48-bit hardware identifier burned into a network interface card
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