- A
The interface bandwidth command is not set to 50000 kbps
Correct because bandwidth percent uses the interface bandwidth value; if it is set to a default (e.g., 1000000 for Ethernet), the percentages do not match the actual link speed.
- B
The voice class should use priority instead of bandwidth
Why wrong: Incorrect because priority provides strict priority, not guaranteed bandwidth; it could starve other classes.
- C
The video class should use bandwidth remaining percent
Why wrong: Incorrect because bandwidth remaining percent allocates leftover bandwidth, not a fixed guarantee; it does not solve the voice under-allocation.
- D
The policy map is applied in the input direction
Why wrong: Incorrect because input direction does not support bandwidth guarantees; bandwidth is only for output policies.
Quick Answer
The answer is that the interface bandwidth command is not set to 50000 kbps, which causes the QoS bandwidth percent statements to calculate based on the default interface bandwidth rather than the actual 50 Mbps link speed. This is because bandwidth percent allocates a percentage of the interface bandwidth value configured under the interface, not the physical line rate; if the interface bandwidth defaults to a different value—often 1.544 Mbps on serial interfaces or another default on Ethernet—the voice class’s 20% will yield far less than the intended 10 Mbps. On the ENCOR 350-401 exam, this scenario tests your understanding that bandwidth percent is a relative allocation tied to the interface bandwidth, not the actual circuit speed, and it’s a common trap to assume the physical link speed is used. A reliable memory tip is “percent is parent-dependent”—always verify the interface bandwidth matches the contracted link speed, or use bandwidth remaining percent for fair sharing when shaping.
CCNP QoS Practice Question
This 350-401 practice question tests your understanding of qos. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
An engineer is configuring QoS on a Cisco ASR 1000 router to support three traffic classes: voice (EF), video (AF41), and data (default). The link is a 50 Mbps Ethernet circuit. The engineer wants to guarantee 10 Mbps for voice, 20 Mbps for video, and the remaining for data. The current policy uses bandwidth percent statements. During congestion, voice traffic is not receiving its guaranteed bandwidth. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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
The interface bandwidth command is not set to 50000 kbps
The correct answer is that bandwidth percent is based on the interface bandwidth, which may not match the actual link speed if the interface bandwidth is not set correctly. The engineer should use bandwidth remaining percent or shape the traffic.
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.
- ✓
The interface bandwidth command is not set to 50000 kbps
Why this is correct
Correct because bandwidth percent uses the interface bandwidth value; if it is set to a default (e.g., 1000000 for Ethernet), the percentages do not match the actual link speed.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The voice class should use priority instead of bandwidth
Why it's wrong here
Incorrect because priority provides strict priority, not guaranteed bandwidth; it could starve other classes.
- ✗
The video class should use bandwidth remaining percent
Why it's wrong here
Incorrect because bandwidth remaining percent allocates leftover bandwidth, not a fixed guarantee; it does not solve the voice under-allocation.
- ✗
The policy map is applied in the input direction
Why it's wrong here
Incorrect because input direction does not support bandwidth guarantees; bandwidth is only for output policies.
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.
Trap categories for this question
Command / output trap
Incorrect because input direction does not support bandwidth guarantees; bandwidth is only for output policies.
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 350-401 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 350-401 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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QoS — study guide chapter
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FAQ
Questions learners often ask
What does this 350-401 question test?
QoS — This question tests QoS — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The interface bandwidth command is not set to 50000 kbps — The correct answer is that bandwidth percent is based on the interface bandwidth, which may not match the actual link speed if the interface bandwidth is not set correctly. The engineer should use bandwidth remaining percent or shape the traffic.
What should I do if I get this 350-401 question wrong?
Identify which 350-401 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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 18, 2026
This 350-401 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 350-401 exam.
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