Question

The corporate IT administrators, Hunter, Rion, and Liam, are huddled together to try to solve an issue with the newly deployed VoWiFi phones. The chosen security solution is PEAPv0 (EAP-MSCHAPv2) for the voice SSID that also has Voice-Enterprise enabled on the access points. The VoWiFi phones are authenticating flawlessly and voice calls are stable when the employees use the devices from their desk. However, there seem to be gaps in the audio and sometimes disconnects when the employees are talking on the VoWiFi phones and move to other areas of the building. What are the possible causes of the interruption of service for the voice calls while the employees are mobile? (Choose all that apply.)

A. VoWiFi phones should be configured only for PSK authentication when roaming is a
requirement.
B. VoWiFi phones are reauthenticating every time they roam to a new AP.
C. VoWiFi phones do not use opportunistic key caching.
D. VoWiFi phones do not support fast BSS transition.

Answer 1

Interruptions in VoWiFi calls when employees are mobile could be due to phones reauthenticating at each AP, lacking opportunistic key caching, or not supporting fast BSS transition.

Step-by-step explanation:

The possible causes of the interruption of service for voice calls when employees are mobile and using Voice over Wi-Fi (VoWiFi) with PEAPv0 (EAP-MSCHAPv2) could be:

• VoWiFi phones are reauthenticating every time they roam to a new AP, which could lead to interruptions as the phone establishes a new connection.
• VoWiFi phones do not use opportunistic key caching, which would otherwise allow for faster reconnection to the network by using previously established keys.
• VoWiFi phones do not support fast BSS transition also known as 802.11r, which is designed to minimize the time required to switch between access points.

It is not recommended to configure VoWiFi phones only for PSK authentication when roaming is a requirement, as it may not provide the same level of security as PEAPv0 (EAP-MSCHAPv2).