Question 146 of 240 from exam 400-351: CCIE Wireless Written Exam

Question 146 of 240 from exam 400-351: CCIE Wireless Written Exam


Your company is using wireless voice clients that have a unicast push-to-talk-function.

DTIM is set to 10

Users report that the audio is choppy.

Which action should you take to try to resolve this issue?



A. B. C. D. E.


The DTIM (Delivery Traffic Indication Message) is a mechanism in Wi-Fi networks that informs clients about the availability of multicast and broadcast frames that may be buffered by the access point. The DTIM interval specifies how often the access point sends a DTIM frame to the clients, which contain a bitmap indicating which multicast or broadcast frames are available. Clients that are in power saving mode wake up only when a DTIM frame is received, and can then retrieve the buffered frames.

In this scenario, the wireless voice clients are using a unicast push-to-talk function, which means that they are not receiving multicast or broadcast traffic. Therefore, changing the DTIM interval is unlikely to improve the voice quality.

The choppy audio could be caused by various factors, such as interference, signal strength, codec settings, or network congestion. One possible cause is that the clients are experiencing delays or packet loss due to power saving mode. When a client is in power saving mode, it may miss some packets that arrive during the sleep period, resulting in gaps in the audio stream. Therefore, disabling power saving mode on the clients could potentially improve the voice quality.

Answer C, "Disable power saving on the wireless device," is the most appropriate action to take in this case, based on the available information. Answers A, B, D, and E are unlikely to solve the problem and may even make it worse by affecting the battery life or the network capacity.

However, it is important to note that disabling power saving mode may have a negative impact on the battery life of the clients, especially if they are mobile devices. Therefore, it is advisable to test the voice quality before and after disabling power saving mode, and to consider other factors that may affect the network performance.