350-401 Question 65
Select 3A network administrator is tasked with implementing a QoS policy on a Cisco router to prioritize voice traffic over regular data traffic. The administrator configures a class map to match voice traffic using DSCP EF (Expedited Forwarding) and applies a policy map to prioritize this traffic. Which of the following steps must be completed to ensure the QoS policy is effective?
- A
Attach the policy map to the interface using the 'service-policy' command.
- B
Specify the bandwidth allocation for the voice traffic in the policy map.
- C
Configure a priority queue for the voice traffic within the policy map.
- D
Enable IP routing to allow QoS policies to function.
- E
Match the voice traffic using the correct DSCP value in the class map.
Show answer and explanation
Correct answers: A, C, E
Explanation
To effectively implement a QoS policy for voice traffic, the policy must be attached to the appropriate interface using the 'service-policy' command. Additionally, a priority queue should be configured for voice traffic to ensure it is given preferential treatment. Lastly, the class map must correctly identify the voice traffic using the appropriate DSCP value (e.g., DSCP EF). Without these steps, the QoS policy will not properly prioritize voice traffic, potentially leading to degraded call quality.
- A. Correct.
Correct: The QoS policy must be attached to an interface using the 'service-policy' command to apply the policy to the traffic passing through that interface.
- B. Incorrect.
Incorrect: While bandwidth allocation is important for certain policies, prioritizing voice traffic typically requires a priority queue rather than bandwidth allocation.
- C. Correct.
Correct: Configuring a priority queue ensures that voice traffic is forwarded with the highest priority, reducing latency and jitter.
- D. Incorrect.
Incorrect: IP routing is not a requirement for QoS policies to function. QoS operates at Layer 3 and above, but it doesn't depend on enabling IP routing.
- E. Correct.
Correct: The class map must accurately match the voice traffic using the appropriate DSCP value (e.g., DSCP EF for high-priority voice traffic) for the policy to work as intended.