The answer is the police rate under the REALTIME class, which limits voice traffic to 10% of bandwidth. Even though priority queuing is configured for the DSCP EF marked traffic, the 'police' command enforces a strict rate limit of 10% of the interface bandwidth; when voice traffic exceeds this policed rate, packets are dropped during congestion, making the police rate the bottleneck rather than the priority queue itself. On the Cisco SPCOR / CCNP Service Provider Core 350-501 exam, this question tests your understanding of how QoS priority queuing with police on PE-CE links interacts—specifically, that a police command applied to a priority class overrides the priority queue’s intent to protect delay-sensitive traffic, a common trap where candidates assume priority queuing alone prevents drops. A key memory tip: “Police before priority punishes voice”—the police rate is the hard ceiling, so always check if a policer is starving the priority queue.
350-501 Services Practice Question
This 350-501 practice question tests your understanding of services. 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.
Exhibit
interface GigabitEthernet0/0/0/0
ipv4 address 10.1.1.1 255.255.255.252
service-policy output QOS_POLICY
!
class-map match-any REALTIME
match precedence 5
match dscp ef
!
policy-map QOS_POLICY
class REALTIME
priority level 1
police rate percent 10
class class-default
bandwidth remaining ratio 1
Refer to the exhibit. A service provider is applying this QoS policy on a PE-CE interface. The business customer complains that voice traffic (marked with DSCP EF) experiences drops during congestion. What is the likely cause?
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 under the REALTIME class is limiting voice traffic to 10% of bandwidth.
The REALTIME class uses the 'police' command to enforce a rate of 10% of the interface bandwidth. When voice traffic marked DSCP EF exceeds this policed rate, packets are dropped, even though the class is configured with priority queuing. The police rate is the bottleneck, not the priority queue itself.
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 police rate under the REALTIME class is limiting voice traffic to 10% of bandwidth.
Why this is correct
Policing drops traffic exceeding 10%.
Related concept
Read the scenario before looking for a memorised answer.
✗
The priority level is set too low; voice should be priority level 4.
Why it's wrong here
Priority level only affects the order of multiple priority queues; level 1 is highest.
✗
The 'bandwidth remaining ratio' command under class-default is starving the priority queue.
Why it's wrong here
The priority queue is not affected by bandwidth remaining ratio.
✗
The policy is applied in the output direction; it should be input.
Why it's wrong here
Output direction is correct for shaping/policing egress traffic.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between priority queuing (which provides low latency) and policing (which enforces a rate limit), leading candidates to overlook that a police rate in a priority class can cause drops even when the priority queue is not congested.
Trap categories for this question
Command / output trap
Output direction is correct for shaping/policing egress traffic.
Detailed technical explanation
How to think about this question
The 'police' command in a priority class creates a strict policer that drops traffic exceeding the configured rate, even if the priority queue has available bandwidth. This is a common misconfiguration because engineers assume priority queuing guarantees no drops, but policing overrides that guarantee. In real-world deployments, voice traffic should be policed only if the provider explicitly limits customer bandwidth; otherwise, shaping or using 'priority' without a police rate is preferred.
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.
Services — This question tests Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The police rate under the REALTIME class is limiting voice traffic to 10% of bandwidth. — The REALTIME class uses the 'police' command to enforce a rate of 10% of the interface bandwidth. When voice traffic marked DSCP EF exceeds this policed rate, packets are dropped, even though the class is configured with priority queuing. The police rate is the bottleneck, not the priority queue itself.
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.
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 →
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. Refer to the exhibit. A network engineer applies this policy on the PE-CE link. What is the expected behavior for VoIP traffic matching the access list?
hard
✓ A.VoIP traffic is given strict priority queuing with up to 30% bandwidth
B.VoIP traffic is dropped if congestion occurs
C.VoIP traffic is shaped to 30% of bandwidth
D.VoIP traffic is queued in the default class with fair-queue
Why A: Option B is correct because priority queue provides strict priority; traffic is not shaped. Option A is wrong because priority does not shape. Option C is wrong because fair-queue is for default class. Option D is wrong because congestion is avoided but not specifically by WRED.
Last reviewed: Jun 11, 2026
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.