Which action enhances the voice application quality of experience?

Refer to the exhibit. A VoWLAN has been deployed at a customer site. and users report that audio is choppy in some areas The exhibit captures a voice exchange between one phone that is associated to the AP at the end of the corridor (172.31 255 101) and another phone that is positioned in a conference room nearby.
Which action enhances the voice application quality of experience?

A. Change the basic rate configuration on the WLC to include 54 Mbps.
B. Change the WLAN QoS profile to platinum.
C. Decrease the AP power level.
D. Disable higher data rates on the controller.

cisco-exams

4 thoughts on “Which action enhances the voice application quality of experience?

  1. The capture shows that Frames on 54mbps and 36mbps are not acknowleged by AP. The selected frame is a retry. Thus, AP can’t acknowlege 54 & 36 mbps. It’s SNR issue, lack of coverage. Phone tries to use hig rate, then without Ack it tries to use lower rates, until it succeeds to deliver the frame and get an ack. It gets it on 12mbps. This downshifting consumes time, so we got choppy voice.

    A – is wrong – it’s already configured, otherwise phone wouldn’t try to use it.
    B – QoS control field is not shown, so we can’t see priority bits. No sign of congestion, AP just cant demodulate the frame. So it’s not queuing issue.
    C – We already have SNR issue on client->AP side, why add the same for AP->client side?
    D – seems good for me – client will not waste time for downshifting from 54mbps to 12mbps, thus no delay and no choppy voice.

    George is wrong, due to disabling LOWER DR will lead to smaller cells.

  2. Disabling higher data rates (answer D) applies to dense AP environments to create smaller cells and enhanced throughput.
    For voice, 24 Mbps is the highest data rate needed, so answer A is not the correct one.

    To ensure best quality, QoS platinum must be used for voice and prioritizes voice packets on the wired network.
    Every documentation I read on voice emphasizes on the need to use QoS and choose the Platinum profile

    1. I think the answer is still A. We can see from the output that 0x28 is used which is CS5 or EF which is platinum leaving on A to be correct.

Leave a Reply

Your email address will not be published. Required fields are marked *


The reCAPTCHA verification period has expired. Please reload the page.