What can greatly impact the application layer throughput of an 802.11n client in a 2.4 GHz HT BSS?

The impact of RF interference from numerous Bluetooth devices on the application layer throughput of an 802.11n client in a 2.4 GHz HT BSS is significant because both Bluetooth and 802.11n operate in the same frequency band. The 2.4 GHz band is relatively crowded, and the presence of multiple Bluetooth devices can introduce interference that degrades the quality of the wireless signal. This interference can result in packet loss, increased latency, and a decrease in the effective data rate, all of which directly affect the throughput experienced by the application layer.

In contrast, using a VPN or connecting to a secure guest Wi-Fi network might introduce latency or overhead due to encryption and additional processing, but these factors typically do not have as direct an impact on throughput as RF interference does. Utilizing maximum allowable data rates can improve throughput under ideal conditions; however, if interference is present, the actual throughput will still be limited. Thus, the presence of Bluetooth devices creating RF interference is the most critical factor impacting the application layer throughput in this scenario.