- A
CRC errors
CRC (Cyclic Redundancy Check) errors indicate that the frame's checksum does not match the computed value, meaning the frame was corrupted during transmission. This is a common interface error that points to physical layer issues such as faulty cabling or excessive noise.
- B
Runts
Why wrong: Runts are frames that are smaller than the minimum allowed size (64 bytes for Ethernet). They are often caused by collisions or faulty hardware, but they are not the same as CRC errors.
- C
Giants
Why wrong: Giants are frames that exceed the maximum allowed size (1518 bytes for standard Ethernet). They are typically caused by misconfigured NICs or software issues, not checksum errors.
- D
Late collisions
Why wrong: Late collisions occur after the first 64 bytes of a frame have been transmitted, indicating a problem with the network diameter or duplex mismatch. They are not related to CRC checksum failures.
Quick Answer
The correct matches are CRC errors with checksum mismatch, Runts with frames under 64 bytes, Giants with oversized frames, and Flaps with repeated link state changes. CRC errors occur when the cyclic redundancy check fails due to noise or faulty cabling, meaning the frame’s computed checksum does not match the transmitted value. Runts are typically caused by collisions truncating frames below the minimum Ethernet size, while giants often result from a malfunctioning NIC that transmits beyond the maximum frame limit. Flaps indicate physical layer instability, such as a loose cable causing the interface to cycle up and down. On the CCNA 200-301 v2 exam, this drag-and-drop question tests your ability to distinguish interface error types by their root causes rather than just symptoms—a common trap is confusing runts with giants based on size alone. Remember the mnemonic: **CRC = Check, Runts = Reduced, Giants = Gargantuan, Flaps = Flaky link**.
CCNA Network Infrastructure and Connectivity Practice Question
This 200-301 practice question tests your understanding of network infrastructure and connectivity. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Drag and drop the interface error types on the left to the corresponding descriptions on the right.
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
CRC errors occur when a frame fails the cyclic redundancy check (checksum mismatch) due to noise or faulty cabling. Runts are frames smaller than 64 bytes, typically caused by collisions. Giants are frames exceeding the maximum frame size, often from a faulty NIC. Flaps are repeated link up/down transitions, usually from loose cables or hardware issues. Input errors is a catch-all counter for all receive-side errors including CRC, runts, giants, and framing errors. Each match is correct because the description aligns with the standard definition; for example, CRC errors specifically involve checksum failure, not frame size or link flapping.
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
Why this is correct
CRC (Cyclic Redundancy Check) errors indicate that the frame's checksum does not match the computed value, meaning the frame was corrupted during transmission. This is a common interface error that points to physical layer issues such as faulty cabling or excessive noise.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Runts
Why it's wrong here
Runts are frames that are smaller than the minimum allowed size (64 bytes for Ethernet). They are often caused by collisions or faulty hardware, but they are not the same as CRC errors.
- ✗
Giants
Why it's wrong here
Giants are frames that exceed the maximum allowed size (1518 bytes for standard Ethernet). They are typically caused by misconfigured NICs or software issues, not checksum errors.
- ✗
Late collisions
Why it's wrong here
Late collisions occur after the first 64 bytes of a frame have been transmitted, indicating a problem with the network diameter or duplex mismatch. They are not related to CRC checksum failures.
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 errorsCorrect answer▾
Why this is correct
CRC (Cyclic Redundancy Check) errors indicate that the frame's checksum does not match the computed value, meaning the frame was corrupted during transmission. This is a common interface error that points to physical layer issues such as faulty cabling or excessive noise.
✗RuntsWrong answer — click to see why▾
Why this is wrong here
Runts are undersized frames, not checksum failures. The description for CRC errors specifically refers to checksum mismatches.
Why candidates choose this
Candidates might confuse runts with CRC errors because both indicate frame corruption, but runts are defined by size, not checksum.
✗GiantsWrong answer — click to see why▾
Why this is wrong here
Giants are oversized frames, not checksum failures. The description for CRC errors is about integrity verification, not frame size.
Why candidates choose this
Candidates might think giants involve CRC errors because oversized frames can also be corrupt, but the error type is distinct.
✗Late collisionsWrong answer — click to see why▾
Why this is wrong here
Late collisions are a timing issue, not a checksum mismatch. CRC errors are detected at the receiver after the entire frame is received.
Why candidates choose this
Candidates might associate late collisions with CRC errors because both can result from physical layer problems, but they are distinct error types.
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
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- 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.
Identify which 200-301 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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Network Infrastructure and Connectivity — study guide chapter
Learn the concepts, then practise the questions
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Network Infrastructure and Connectivity practice questions
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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 — CRC errors occur when a frame fails the cyclic redundancy check (checksum mismatch) due to noise or faulty cabling. Runts are frames smaller than 64 bytes, typically caused by collisions. Giants are frames exceeding the maximum frame size, often from a faulty NIC. Flaps are repeated link up/down transitions, usually from loose cables or hardware issues. Input errors is a catch-all counter for all receive-side errors including CRC, runts, giants, and framing errors. Each match is correct because the description aligns with the standard definition; for example, CRC errors specifically involve checksum failure, not frame size or link flapping.
What should I do if I get this 200-301 question wrong?
Identify which 200-301 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more ways this is tested on 200-301
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which TWO interface error counters indicate a Layer 1 issue?
medium- ✓ A.CRC errors
- B.Output queue drops
- ✓ C.Runts
- D.Input errors
- E.Ignored packets
Why A: CRC errors occur when the cyclic redundancy check computed at the receiver does not match the value appended by the sender, indicating that the frame was corrupted during transmission. This corruption is typically caused by physical-layer problems such as faulty cabling, bad connectors, or excessive electrical noise. Runts are frames that are smaller than the minimum Ethernet frame size of 64 bytes (excluding preamble), and they often result from collisions or transceiver issues that are Layer 1 phenomena. Both counters directly point to physical-layer impairments rather than logical or congestion-related issues.
Last reviewed: Jun 6, 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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