- A
Traffic matching DSCP AF21, AF22, or AF23 is guaranteed 50% of the interface bandwidth, and all other traffic is subject to fair-queuing.
Correct. 'bandwidth remaining percent' guarantees a percentage of the bandwidth left after priority queues, and the default class uses fair-queue.
- B
Only traffic with DSCP AF21 is matched; AF22 and AF23 are ignored because 'match-any' requires all conditions to be true.
Why wrong: Incorrect. 'match-any' means any one of the conditions is sufficient for a match.
- C
The configuration is invalid because 'bandwidth remaining percent' cannot be used with 'fair-queue' in the same policy-map.
Why wrong: Incorrect. They can be used together; 'bandwidth remaining percent' allocates a share, and 'fair-queue' provides fairness within the default class.
- D
The policy-map will only be applied to incoming traffic on GigabitEthernet0/0.
Why wrong: Incorrect. The 'service-policy output' command applies the policy to outgoing traffic.
Quick Answer
The correct answer is that traffic matching DSCP AF21, AF22, or AF23 is guaranteed 50% of the interface bandwidth, and all other traffic is subject to fair-queuing. This is because the bandwidth remaining percent 50 command allocates a proportional share of any leftover bandwidth—after priority queues are serviced—to the CRITICAL_DATA class, while the fair-queue command in class-default ensures that all other traffic is distributed evenly among flows based on queue depth. On the ENCOR 350-401 exam, this configuration tests your understanding of how bandwidth remaining percent interacts with fair-queue in a class-map, a common scenario where candidates mistakenly think the 50% is a hard cap rather than a minimum guarantee of remaining bandwidth. A frequent trap is confusing bandwidth remaining percent with the bandwidth command, which reserves a strict amount; here, the key is that fair-queue only applies to the default class, not the explicitly defined class. Memory tip: think of “remaining” as “leftover pie”—the CRITICAL_DATA class gets half of what’s left after priority, and the rest is shared fairly.
CCNP QoS Practice Question
This 350-401 practice question tests your understanding of qos. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
Consider the following configuration on a Cisco router:
class-map match-any CRITICAL_DATA match ip dscp af21 af22 af23
policy-map QOS
class CRITICAL_DATA
bandwidth remaining percent 50
class class-default
fair-queue
interface GigabitEthernet0/0
service-policy output QOS
Which statement about this configuration is true?
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
Traffic matching DSCP AF21, AF22, or AF23 is guaranteed 50% of the interface bandwidth, and all other traffic is subject to fair-queuing.
The class-map matches DSCP values AF21, AF22, and AF23 (which are Assured Forwarding classes). The policy-map allocates 50% of remaining bandwidth to this class after any priority queues, and uses fair-queue for the default class.
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.
- ✓
Traffic matching DSCP AF21, AF22, or AF23 is guaranteed 50% of the interface bandwidth, and all other traffic is subject to fair-queuing.
Why this is correct
Correct. 'bandwidth remaining percent' guarantees a percentage of the bandwidth left after priority queues, and the default class uses fair-queue.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Only traffic with DSCP AF21 is matched; AF22 and AF23 are ignored because 'match-any' requires all conditions to be true.
Why it's wrong here
Incorrect. 'match-any' means any one of the conditions is sufficient for a match.
- ✗
The configuration is invalid because 'bandwidth remaining percent' cannot be used with 'fair-queue' in the same policy-map.
Why it's wrong here
Incorrect. They can be used together; 'bandwidth remaining percent' allocates a share, and 'fair-queue' provides fairness within the default class.
- ✗
The policy-map will only be applied to incoming traffic on GigabitEthernet0/0.
Why it's wrong here
Incorrect. The 'service-policy output' command applies the policy to outgoing traffic.
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. The 'service-policy output' command applies the policy to outgoing traffic.
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.
- →
QoS — study guide chapter
Learn the concepts, then practise the questions
- →
QoS practice questions
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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: Traffic matching DSCP AF21, AF22, or AF23 is guaranteed 50% of the interface bandwidth, and all other traffic is subject to fair-queuing. — The class-map matches DSCP values AF21, AF22, and AF23 (which are Assured Forwarding classes). The policy-map allocates 50% of remaining bandwidth to this class after any priority queues, and uses fair-queue for the default class.
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.
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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