The availability and reasonable cost of broadband Internet made it an attractive and favourable option to billions of users worldwide. Being a fast service also encourages its users to use real-time applications which is streaming and live data transfer includes VoIP and video streaming. The performance of such applications in Wireless Local Area Network (WLAN) may be highly affected by security protocols. This paper examines the effect of different security protocols on the performance of WLAN with real-time application and live data transfer applications. Experiments were performed on a wireless test-bed and the results were analyzed for signal strength, throughput, delay, packet loss, jitter and mean opinion score (MOS) for two security settings which are without security and Wi-Fi Protected Access 2 (WPA2). This paper investigates the impact of security on the performance of 2.4 GHz WLAN Network. The results revealed a significant degradation in performance when security protocols were enabled in WLAN. This paper also addresses the different issues related to the security protocols currently used in WLAN and demonstrates how these issues affect the final results of the experiments conducted. The results show that within the same access point range the security adds moderate degradation on the throughput that may affect some applications over both infrastructure and ad hoc WLANs.