- A
CBWFQ allows you to define multiple classes and assign each a guaranteed minimum bandwidth.
Correct because CBWFQ allocates bandwidth to each class based on the 'bandwidth' command.
- B
LLQ combines a strict priority queue with CBWFQ classes to support real-time traffic.
Correct because LLQ uses the 'priority' command to create a strict priority queue alongside CBWFQ.
- C
Weighted Fair Queuing (WFQ) is the default queuing mechanism on all Cisco router interfaces.
Why wrong: Incorrect because WFQ is the default only on low-speed interfaces (below 2.048 Mbps); high-speed interfaces use FIFO by default.
- D
Tail drop is the only drop policy available for CBWFQ queues.
Why wrong: Incorrect because CBWFQ can also use WRED (Weighted Random Early Detection) as a drop policy to avoid tail drop.
- E
FIFO queuing provides per-class bandwidth guarantees.
Why wrong: Incorrect because FIFO is a single queue without any bandwidth differentiation or guarantees.
Quick Answer
The answer is that LLQ combines a strict priority queue with CBWFQ classes to support real-time traffic. This is correct because CBWFQ (Class-Based Weighted Fair Queuing) guarantees bandwidth to defined traffic classes, but it cannot prevent delay-sensitive packets like voice from being queued behind less urgent data. LLQ solves this by adding a strict priority queue that services real-time traffic before any other CBWFQ class, ensuring low latency and jitter for voice and video. On the ENCOR 350-401 exam, this concept tests your understanding of how congestion management balances bandwidth guarantees with delay requirements—a common trap is confusing LLQ’s priority queue with simple CBWFQ, which lacks a priority mechanism. Remember that WFQ is the default on low-speed interfaces, FIFO on high-speed, and tail drop applies to both FIFO and CBWFQ. For a quick memory tip: think of LLQ as “CBWFQ plus a VIP lane” for real-time traffic.
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.
Which two statements about queuing and congestion management are true? (Choose two.)
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
CBWFQ allows you to define multiple classes and assign each a guaranteed minimum bandwidth.
CBWFQ provides guaranteed bandwidth to classes, while LLQ adds a strict priority queue for delay-sensitive traffic. WFQ is the default on low-speed interfaces. FIFO is used on high-speed interfaces by default. Tail drop is the default drop policy for FIFO and CBWFQ queues.
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.
- ✓
CBWFQ allows you to define multiple classes and assign each a guaranteed minimum bandwidth.
Why this is correct
Correct because CBWFQ allocates bandwidth to each class based on the 'bandwidth' command.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
LLQ combines a strict priority queue with CBWFQ classes to support real-time traffic.
Why this is correct
Correct because LLQ uses the 'priority' command to create a strict priority queue alongside CBWFQ.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Weighted Fair Queuing (WFQ) is the default queuing mechanism on all Cisco router interfaces.
Why it's wrong here
Incorrect because WFQ is the default only on low-speed interfaces (below 2.048 Mbps); high-speed interfaces use FIFO by default.
- ✗
Tail drop is the only drop policy available for CBWFQ queues.
Why it's wrong here
Incorrect because CBWFQ can also use WRED (Weighted Random Early Detection) as a drop policy to avoid tail drop.
- ✗
FIFO queuing provides per-class bandwidth guarantees.
Why it's wrong here
Incorrect because FIFO is a single queue without any bandwidth differentiation or guarantees.
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 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
Targeted practice on this topic area only
- →
All 350-401 questions
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- →
ENCOR 350-401 study guide
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350-401 practice test guide
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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: CBWFQ allows you to define multiple classes and assign each a guaranteed minimum bandwidth. — CBWFQ provides guaranteed bandwidth to classes, while LLQ adds a strict priority queue for delay-sensitive traffic. WFQ is the default on low-speed interfaces. FIFO is used on high-speed interfaces by default. Tail drop is the default drop policy for FIFO and CBWFQ queues.
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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