- A
VOICE traffic is guaranteed 10% of the interface bandwidth with strict priority queuing, VIDEO traffic is guaranteed 30%, and all other traffic shares the remaining bandwidth using fair-queuing.
Correct. The 'priority' command provides strict priority queuing with a bandwidth guarantee, and 'fair-queue' enables fair sharing among the default class.
- B
VOICE traffic is limited to 10% of bandwidth, VIDEO to 30%, and all other traffic is dropped if the interface is congested.
Why wrong: Incorrect. The 'fair-queue' command does not drop traffic; it provides fair sharing.
- C
VOICE traffic is given priority over VIDEO, but VIDEO can use up to 30% of bandwidth only if VOICE is not using its allocation.
Why wrong: Incorrect. The 'priority' command gives strict priority, but VIDEO is guaranteed bandwidth regardless of VOICE usage.
- D
The policy-map is invalid because 'priority' and 'bandwidth' cannot be used together in the same policy-map.
Why wrong: Incorrect. 'priority' and 'bandwidth' can be used in different classes within the same policy-map.
Quick Answer
The answer is that VOICE traffic receives strict priority queuing with a guaranteed 10% bandwidth allocation, VIDEO traffic is guaranteed 30% of the interface bandwidth, and all other traffic shares the remaining 60% via fair-queuing. This configuration effect stems from how Low Latency Queuing (LLQ) combines a strict priority queue for delay-sensitive traffic with guaranteed bandwidth classes and a default fair-queue class. On the ENCOR 350-401 exam, this tests your understanding of the LLQ priority queue bandwidth configuration effect, specifically that the priority command creates a strict priority queue that can starve other queues if not policed, while the bandwidth command provides a minimum guaranteed rate. A common trap is assuming the priority class consumes only its allocated percentage, but in LLQ, priority traffic can burst beyond its allocation if bandwidth is available, potentially impacting the VIDEO class. Remember the mnemonic: “Priority first, bandwidth second, fair-queue last” to recall the queuing hierarchy and avoid misinterpreting the bandwidth guarantee as a hard limit.
350-401 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.
Examine the following configuration snippet on a Cisco IOS-XE router:
interface GigabitEthernet0/1
service-policy output QOS_POLICY
policy-map QOS_POLICY
class VOICE
priority percent 10
class VIDEO
bandwidth percent 30
class class-default
fair-queue
What is the effect of this configuration?
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
VOICE traffic is guaranteed 10% of the interface bandwidth with strict priority queuing, VIDEO traffic is guaranteed 30%, and all other traffic shares the remaining bandwidth using fair-queuing.
The policy-map applies a priority queue for VOICE traffic, guarantees bandwidth for VIDEO, and uses fair-queue for all other traffic on the output interface.
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.
- ✓
VOICE traffic is guaranteed 10% of the interface bandwidth with strict priority queuing, VIDEO traffic is guaranteed 30%, and all other traffic shares the remaining bandwidth using fair-queuing.
Why this is correct
Correct. The 'priority' command provides strict priority queuing with a bandwidth guarantee, and 'fair-queue' enables fair sharing among the default class.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
VOICE traffic is limited to 10% of bandwidth, VIDEO to 30%, and all other traffic is dropped if the interface is congested.
Why it's wrong here
Incorrect. The 'fair-queue' command does not drop traffic; it provides fair sharing.
- ✗
VOICE traffic is given priority over VIDEO, but VIDEO can use up to 30% of bandwidth only if VOICE is not using its allocation.
Why it's wrong here
Incorrect. The 'priority' command gives strict priority, but VIDEO is guaranteed bandwidth regardless of VOICE usage.
- ✗
The policy-map is invalid because 'priority' and 'bandwidth' cannot be used together in the same policy-map.
Why it's wrong here
Incorrect. 'priority' and 'bandwidth' can be used in different classes within the same policy-map.
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 'fair-queue' command does not drop traffic; it provides fair sharing.
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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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: VOICE traffic is guaranteed 10% of the interface bandwidth with strict priority queuing, VIDEO traffic is guaranteed 30%, and all other traffic shares the remaining bandwidth using fair-queuing. — The policy-map applies a priority queue for VOICE traffic, guarantees bandwidth for VIDEO, and uses fair-queue for all other traffic on the output interface.
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
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 →
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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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