Wireless Voice Disruptions: Possible Causes and Solutions

Identifying TKIP Replay Messages: Troubleshooting Voice Disruptions


You have been getting reports of voice disruption over wireless communications in your network.

Your SSID is configured to use WPA1 with TKIP and Cisco Centralized Key Management.

You see a lot of TKIP replay messages on the WLC logs.

What is the most probable reason for the voice disruptions?



Click on the arrows to vote for the correct answer

A. B. C. D.


The issue of voice disruption over wireless communications in a network that uses WPA1 with TKIP and Cisco Centralized Key Management is a common problem. When this problem occurs, it can be frustrating for users, as they may experience problems such as call drops, poor call quality, or complete voice communication loss.

One possible reason for the voice disruption is the occurrence of TKIP replay messages. TKIP (Temporal Key Integrity Protocol) is a security protocol used to encrypt wireless traffic. TKIP replay messages occur when a hacker captures and replays encrypted packets, which can lead to the decryption of the packet's contents.

The most probable reason for voice disruptions in this scenario is the activation of MFP (Management Frame Protection) triggered by the TKIP replay. MFP is a security feature that is designed to protect the network against forged management frames. MFP detects the TKIP replay, which then triggers MFP to disassociate all wireless clients, including those carrying voice traffic.

Therefore, the answer is C: TKIP replay activates MFP. If MFP detects the replays, it will trigger a disassociation to all wireless clients. This leads to voice disruptions in the network.

Option A, which states that TKIP replay causes the access point to reboot, is not correct because this is not a security measure that access points take. Moreover, even if it was true, the reboots would not explain the voice disruptions.

Option B, which states that the TKIP countermeasure timer is putting the AP down, is not correct either. TKIP countermeasures are designed to stop the hacker from capturing and replaying packets. Still, they do not put the AP down for any specified time that could cause voice disruptions.

Option D, which suggests that the use of WPA1 with TKIP is the main reason for the voice disruptions, is not entirely accurate. While using WPA2 with AES is generally considered more secure than using WPA1 with TKIP, the use of WPA1 with TKIP alone would not cause voice disruptions. The cause is the activation of MFP due to TKIP replay.