350-401 Question 66
Single answerA network administrator is tasked with implementing a QoS policy to prioritize voice traffic over other types of traffic in a campus network. The policy should ensure low latency for voice traffic while preventing bandwidth starvation for other applications. Which QoS mechanism is most appropriate for achieving this requirement?
- A
Priority Queuing (PQ)
- B
Class-Based Weighted Fair Queuing (CBWFQ)
- C
Weighted Random Early Detection (WRED)
- D
Best-Effort Delivery
Show answer and explanation
Correct answer: B
Explanation
Class-Based Weighted Fair Queuing (CBWFQ) is the most appropriate mechanism for this scenario. It supports the creation of a low latency queue (LLQ) for voice traffic, ensuring low latency. Additionally, CBWFQ allocates guaranteed bandwidth to other traffic classes, preventing bandwidth starvation for non-voice applications. This makes it ideal for scenarios where voice traffic needs prioritization without negatively impacting other traffic types.
- A. Incorrect.
Priority Queuing (PQ) ensures low latency for voice traffic by always servicing the high-priority queue first, but it can lead to bandwidth starvation for lower-priority traffic, violating the requirement.
- B. Correct.
Class-Based Weighted Fair Queuing (CBWFQ) allows for prioritization of voice traffic using a low latency queue but also allocates bandwidth to other traffic classes, ensuring no traffic is starved, which satisfies the scenario's requirement.
- C. Incorrect.
Weighted Random Early Detection (WRED) is used for congestion avoidance by dropping packets probabilistically but does not actively prioritize voice traffic, making it unsuitable for this requirement.
- D. Incorrect.
Best-Effort Delivery does not provide any prioritization or guarantees for traffic, so it cannot meet the scenario's need for prioritizing voice traffic while ensuring fair treatment of other traffic.