350-401 Question 60
Select 3A network administrator is tasked with configuring Quality of Service (QoS) on a wired and wireless network to prioritize VoIP traffic. The administrator applies the following configurations:
- On the wired network, a policy-map is configured to prioritize traffic with DSCP value EF (Expedited Forwarding).
- On the wireless network, the QoS profile assigns traffic to WMM Access Category Voice.
What is the expected result of these configurations, and what additional considerations should be made to ensure end-to-end QoS for VoIP traffic?
- A
VoIP traffic will be prioritized on both wired and wireless networks as long as DSCP values are preserved end-to-end.
- B
The wireless QoS configuration will overwrite DSCP markings with UP (User Priority) values when traffic enters the wireless medium.
- C
The wired QoS configuration has no effect unless configured on all switches in the network path.
- D
Traffic in the WMM Voice category will always be prioritized over all other wireless traffic, regardless of other QoS settings.
- E
QoS configurations must also account for congestion points such as WAN links to fully optimize VoIP performance.
Show answer and explanation
Correct answers: A, B, E
Explanation
To ensure end-to-end QoS for VoIP traffic, it is crucial to consider both wired and wireless configurations. DSCP values must be preserved to maintain consistent prioritization, and the mapping to UP values on wireless networks must be understood. Additionally, congestion points like WAN links should be accounted for to avoid performance degradation, ensuring optimal prioritization of VoIP traffic across the entire network.
- A. Correct.
Correct: DSCP values must be preserved across the network to ensure QoS policies can be consistently applied.
- B. Correct.
Correct: Wireless QoS often maps DSCP values to UP values for WMM categories, which may require additional consideration for end-to-end QoS.
- C. Incorrect.
Incorrect: Wired QoS policies do not need to be applied to all switches, only to those in the traffic path where prioritization or congestion management is required.
- D. Incorrect.
Incorrect: While WMM Voice traffic is prioritized, it does not guarantee absolute priority over all other traffic unless explicitly configured, and other factors like airtime fairness may influence behavior.
- E. Correct.
Correct: QoS configurations must consider all potential congestion points, such as WAN links, to avoid bottlenecks that could degrade VoIP performance.