- A
CRC errors indicate that frames were received with an invalid checksum, often due to cabling issues.
CRC errors occur when the cyclic redundancy check fails, indicating data corruption. This is commonly caused by faulty or noisy cabling.
- B
Runts are frames that are larger than the maximum allowed size.
Why wrong: Runts are frames smaller than 64 bytes (the minimum Ethernet frame size). Giants are frames larger than the maximum size (1518 bytes without VLAN tagging).
- C
Giants are frames that are smaller than 64 bytes.
Why wrong: Giants are frames larger than the maximum allowed size. Runts are smaller than 64 bytes.
- D
Input errors include runts, giants, CRC errors, and frame errors.
The 'show interface' command groups runts, giants, CRC errors, and frame errors under 'input errors'.
- E
Flaps indicate that the interface is physically disconnected.
Why wrong: Flaps refer to the interface going up and down repeatedly, not necessarily a permanent disconnection. A single disconnection is not a flap.
Quick Answer
The correct answer identifies that CRC errors indicate frames received with an invalid checksum, often due to cabling issues, and that input errors is a cumulative counter including runts, giants, CRC errors, and frame errors. CRC errors occur when the frame’s cyclic redundancy check fails, meaning the data was corrupted during transmission, typically from faulty cables, bad connectors, or electromagnetic interference. On the CCNA 200-301 v2 exam, the "show interface errors" interpretation tests your ability to differentiate between specific error types and their root causes—a common trap is confusing runts (frames under 64 bytes) with giants (frames over 1518 bytes), or assuming flaps always mean a physical disconnect when they can stem from duplex mismatches. For a quick memory tip, remember that CRC errors are "cable-related corruption," and input errors are the "big bucket" that catches all the smaller frame problems.
CCNA Network Infrastructure and Connectivity Practice Question
This 200-301 practice question tests your understanding of network infrastructure and connectivity. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which TWO of the following are valid interpretations of errors seen in the output of the 'show interface' command?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
CRC errors indicate that frames were received with an invalid checksum, often due to cabling issues.
CRC errors (option A) indicate frames with an invalid checksum, often due to cabling issues, which is correct. Option D is also correct: 'Input errors' is a cumulative counter that includes runts, giants, CRC errors, and frame errors. Option B is wrong because runts are frames smaller than 64 bytes, not larger. Option C is wrong because giants are frames larger than the maximum allowed size (typically 1518 bytes), not smaller than 64 bytes. Option E is wrong because 'flaps' refer to an interface going up and down repeatedly, not necessarily physically disconnected; it could be due to duplex mismatch or other reasons.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
CRC errors indicate that frames were received with an invalid checksum, often due to cabling issues.
Why this is correct
CRC errors occur when the cyclic redundancy check fails, indicating data corruption. This is commonly caused by faulty or noisy cabling.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Runts are frames that are larger than the maximum allowed size.
Why it's wrong here
Runts are frames smaller than 64 bytes (the minimum Ethernet frame size). Giants are frames larger than the maximum size (1518 bytes without VLAN tagging).
- ✗
Giants are frames that are smaller than 64 bytes.
Why it's wrong here
Giants are frames larger than the maximum allowed size. Runts are smaller than 64 bytes.
- ✓
Input errors include runts, giants, CRC errors, and frame errors.
Why this is correct
The 'show interface' command groups runts, giants, CRC errors, and frame errors under 'input errors'.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Flaps indicate that the interface is physically disconnected.
Why it's wrong here
Flaps refer to the interface going up and down repeatedly, not necessarily a permanent disconnection. A single disconnection is not a flap.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓CRC errors indicate that frames were received with an invalid checksum, often due to cabling issues.Correct answer▾
Why this is correct
CRC errors occur when the cyclic redundancy check fails, indicating data corruption. This is commonly caused by faulty or noisy cabling.
✗Runts are frames that are larger than the maximum allowed size.Wrong answer — click to see why▾
Why this is wrong here
Runts are frames smaller than 64 bytes, not larger. The minimum Ethernet frame size is 64 bytes; frames below this are considered runts and are often caused by collisions or faulty hardware.
Why candidates choose this
Students may confuse 'runts' with 'giants' due to the opposite-sounding names, or assume 'runts' refers to something undersized but incorrectly think it means oversized.
✗Giants are frames that are smaller than 64 bytes.Wrong answer — click to see why▾
Why this is wrong here
Giants are frames larger than the maximum allowed size (typically 1518 bytes without VLAN tagging), not smaller than 64 bytes. The description given is actually for runts.
Why candidates choose this
The terms 'runts' and 'giants' are easily confused because they are opposites; a student might mistakenly swap their definitions.
✗Flaps indicate that the interface is physically disconnected.Wrong answer — click to see why▾
Why this is wrong here
Flaps refer to an interface repeatedly transitioning between up and down states, not a single disconnection. A physical disconnection would show the interface as 'down' but not necessarily as a flap unless it reconnects and disconnects repeatedly.
Why candidates choose this
The term 'flap' might be interpreted as a single change in state (like a flap of a wing), but in networking it specifically implies repeated transitions.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the exact byte thresholds for runts (less than 64 bytes) and giants (greater than 1518 bytes), and candidates frequently reverse these values or confuse them with other error types.
Detailed technical explanation
How to think about this question
The 'show interface' command displays counters that increment for specific frame errors: runts (frames < 64 bytes with valid FCS), giants (frames > 1518 bytes), and CRC errors (frames of valid size but with FCS mismatch). In real-world scenarios, a duplex mismatch often causes both CRC errors and runts because collisions are not properly handled, leading to truncated or corrupted frames.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 200-301 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this 200-301 question test?
Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: CRC errors indicate that frames were received with an invalid checksum, often due to cabling issues. — CRC errors (option A) indicate frames with an invalid checksum, often due to cabling issues, which is correct. Option D is also correct: 'Input errors' is a cumulative counter that includes runts, giants, CRC errors, and frame errors. Option B is wrong because runts are frames smaller than 64 bytes, not larger. Option C is wrong because giants are frames larger than the maximum allowed size (typically 1518 bytes), not smaller than 64 bytes. Option E is wrong because 'flaps' refer to an interface going up and down repeatedly, not necessarily physically disconnected; it could be due to duplex mismatch or other reasons.
What should I do if I get this 200-301 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.
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