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350-401 Practice Question: Consider the following partial configuration for…
Consider the following partial configuration for QoS on a Cisco IOS-XE router:
class-map match-all VOICE match ip dscp ef ! policy-map QOS_POLICY
class VOICE
priority 1000
class class-default
fair-queue !
interface GigabitEthernet0/0
service-policy output QOS_POLICY
What is the effect of the 'priority 1000' command under class VOICE?
⚠ Common exam trap
The trap is confusing priority with bandwidth; candidates may think priority 1000 guarantees 1000 kbps without dropping, but it actually polices and drops excess traffic during congestion.
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 placed in a strict priority queue with a bandwidth limit of 1000 kbps.
The 'priority 1000' command under a class in a policy-map enables Low Latency Queuing (LLQ) for that class, placing its traffic in a strict priority queue. The value 1000 specifies the bandwidth limit in kbps that the priority queue is policed to; traffic exceeding this rate is dropped when congestion occurs. This ensures voice traffic gets low latency while preventing it from starving other classes.
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 placed in a strict priority queue with a bandwidth limit of 1000 kbps.
Why this is correct
The `priority` command creates a low-latency queue serviced before other classes, and its 1000 value sets the guaranteed bandwidth in kbps. This satisfies the stem's requirement to identify the effect of `priority 1000`: voice traffic receives strict priority scheduling capped at 1000 kbps, while `fair-queue` handles remaining class-default traffic.
- ✗
Voice traffic is given a minimum bandwidth guarantee of 1000 kbps but no priority.
Why it's wrong here
The priority command provides both a bandwidth guarantee and strict-priority low-latency queueing, not bandwidth alone. It is tempting because the kbps value resembles the bandwidth command, and bandwidth would be correct where a minimum guaranteed share without latency sensitivity is required, such as bulk data.
- ✗
Voice traffic is dropped if it exceeds 1000 kbps.
Why it's wrong here
Excess traffic in a priority class is policed, but the priority command itself does not drop all traffic above 1000 kbps; it guarantees strict-priority scheduling up to that rate. It is tempting because policing is the mechanism policing excess, and a pure police command would be correct where hard rate enforcement without latency guarantees is required.
- ✗
Voice traffic is shaped to 1000 kbps.
Why it's wrong here
Shaping buffers excess traffic to a configured rate, whereas the priority keyword enables low-latency queueing with policing of excess. It is tempting because a numeric kbps value suggests a rate limit, and shaping would be correct where smooth egress pacing of a traffic class is required rather than strict latency treatment.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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.