The answer is that the police rate for the video queue is too low and must be increased to at least 20 Mbps. This is because in LLQ, the strict priority queue uses a policer to enforce a maximum rate; when the actual video traffic averages 15 Mbps with bursts to 18 Mbps, the 10 Mbps police rate causes immediate drops, leading to jitter and packet loss. The bandwidth command under the priority statement only reserves bandwidth for the queue during congestion or for shaping, but the policer is the active enforcement mechanism that triggers drops. On the Cisco SPCOR 350-501 exam, this scenario tests your understanding that LLQ priority queue policing overrides the bandwidth command, and a common trap is confusing the police rate with the guaranteed contract rate. Remember: the police rate is the hard ceiling—if traffic exceeds it, drops happen regardless of the bandwidth statement. Memory tip: “Police the peak, bandwidth is just a seat.”
350-501 Automation and Quality of Service Practice Question
This 350-501 practice question tests your understanding of automation and quality of service. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
A service provider operates a large MPLS network with hundreds of PE routers. They have deployed QoS policies to ensure real-time traffic (voice and video) receives priority. The policy uses LLQ with a strict priority queue for voice (DSCP EF) and another for video (DSCP AF41). Each priority queue has a policer to prevent starvation of other classes. Recently, a customer reports that their video calls are experiencing jitter and packet loss. The engineer examines the PE router connected to this customer. The interface is GigabitEthernet0/0/1 with the policy applied in the output direction. Show commands indicate that the video priority queue is frequently dropping packets, while the voice queue has no drops. The police for the video queue is set to 10 Mbps. The customer's contract guarantees 20 Mbps for video traffic. However, the actual video traffic is averaging 15 Mbps with bursts to 18 Mbps. The engineer notes that the video class also has a bandwidth command of 10 Mbps under the priority statement. What is the most likely cause of the video packet loss?
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 the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The police rate for the video queue is too low; increase it to at least 20 Mbps.
The video priority queue is dropping packets because the police rate (10 Mbps) is lower than the actual traffic rate (15 Mbps average, bursts to 18 Mbps). In LLQ, the priority queue uses a policer to enforce a maximum rate; traffic exceeding the police rate is dropped. The bandwidth command under priority only reserves bandwidth for the queue in the absence of congestion or for shaping purposes, but the policer is the active enforcement mechanism that causes drops. Increasing the police rate to at least 20 Mbps aligns with the customer's guaranteed rate and prevents drops.
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 bandwidth command under priority is too low; increase it to 20 Mbps.
Why it's wrong here
Bandwidth under priority does not limit the queue; it affects the remaining queues.
✗
The video queue is using the wrong queue limit; increase the queue limit to accommodate bursts.
Why it's wrong here
Queue limit affects tail drops; but the loss is due to policing, not queue fullness.
✗
The video traffic is not being classified correctly; check the class-map match criteria.
Why it's wrong here
Traffic is being classified (drops indicate matching), so classification is correct.
✓
The police rate for the video queue is too low; increase it to at least 20 Mbps.
Why this is correct
The policer drops traffic exceeding 10 Mbps, causing loss for 15-18 Mbps traffic.
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.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between the bandwidth command (which reserves bandwidth for CBWFQ) and the policer rate (which enforces a hard limit on priority traffic), leading candidates to mistakenly think increasing bandwidth will solve the drops.
Detailed technical explanation
How to think about this question
In Cisco LLQ, the priority command can include an optional policer (e.g., `priority 10000` sets a police rate of 10 Mbps). The policer uses a token bucket to enforce the rate; traffic exceeding the committed information rate (CIR) is dropped or remarked. The bandwidth command under priority is used only for bandwidth reporting and does not enforce a hard limit. In real-world deployments, misconfiguring the police rate lower than the contracted rate is a common cause of packet loss for real-time traffic.
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.
TExam Day Tips
→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 350-501 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 exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Automation and Quality of Service — This question tests Automation and Quality of Service — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The police rate for the video queue is too low; increase it to at least 20 Mbps. — The video priority queue is dropping packets because the police rate (10 Mbps) is lower than the actual traffic rate (15 Mbps average, bursts to 18 Mbps). In LLQ, the priority queue uses a policer to enforce a maximum rate; traffic exceeding the police rate is dropped. The bandwidth command under priority only reserves bandwidth for the queue in the absence of congestion or for shaping purposes, but the policer is the active enforcement mechanism that causes drops. Increasing the police rate to at least 20 Mbps aligns with the customer's guaranteed rate and prevents drops.
What should I do if I get this 350-501 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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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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. A service provider is implementing QoS on an MPLS network to support voice, video, and data traffic. Which queuing mechanism provides the lowest latency for real-time traffic?
easy
A.FIFO
B.WRED
✓ C.LLQ
D.CBWFQ
Why C: LLQ (Low Latency Queuing) is the correct choice because it provides a strict priority queue specifically designed for real-time traffic like voice and video. By placing delay-sensitive packets into a dedicated priority queue that is serviced before all other queues, LLQ ensures minimal and predictable latency, which is essential for maintaining voice quality in an MPLS network.
Last reviewed: Jun 25, 2026
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This 350-501 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 350-501 exam.
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