350-501 Services Practice Question
A network engineer is configuring QoS on a Cisco ASR 9000 router to support multiple traffic classes. The policy must ensure that real-time traffic (EF) is not starved by high-volume bulk data (AF11). Which queuing strategy should be applied to the EF class to provide low latency and strict priority?
⚠ Common exam trap
Cisco often tests the misconception that CBWFQ alone can provide low latency for real-time traffic, but the trap is that CBWFQ lacks a strict priority queue, so candidates must recognize that LLQ is required for EF traffic to avoid delay and jitter.
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
✓
Priority Queuing (LLQ)
Low Latency Queuing (LLQ) is the correct choice because it combines strict priority queuing with CBWFQ, ensuring that EF (real-time) traffic is always served before other queues. This prevents starvation of delay-sensitive traffic by bulk data (AF11) while still allowing fair treatment of other classes. LLQ is the standard Cisco mechanism for supporting real-time traffic like VoIP with guaranteed low latency.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Weighted Round Robin (WRR)
Why it's wrong here
WRR does not provide strict priority.
- ✗
Class-Based Weighted Fair Queuing (CBWFQ)
Why it's wrong here
CBWFQ does not provide strict priority.
- ✓
Priority Queuing (LLQ)
Why this is correct
LLQ provides a strict priority queue for EF traffic.
- ✗
First-In-First-Out (FIFO)
Why it's wrong here
FIFO offers no priority or QoS differentiation.
Go deeper
Related to this question
About these practice questions
Courseiva writes every 350-501 question from scratch — 971 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.