RESEARCH OBJECTIVE: The key objective of the research is to find out the impact of enabling security protocols on the WLAN performance in a real test bed environment. The research has measured the 802.11ac WLAN performance with WLAN security protocols enabled and disabled. Moreover, this research has used the IPv4 as well as IPv6, with TCP/UDP packet types. The collected data has been analysed in order to answer the research questions in chapter four. The overarching aim of this research is to evaluate the network performance of the latest approved IEEE WLAN standard “802.11ac” under various security protocols in Windows environment using TCP and UDP traffic for both IP versions (IPv4 & IPv6). The research was launched in a real test-bed setup, with a Client/Server network structure. The research involved an experiment that consisted of two PCs with Windows 10, Windows Server 2012 operating systems and one AP (Access Point). The performance was evaluated through the application of four different test cases. In the first test scenario, the standard network was configured with no security protocol enabled, which is known as open system. The other three test cases consisted of standard networks with security protocols enabled in each stage as WEP, WPA, and WPA2 respectively. The metrics that were used to measure network performance included throughput, round trip time (RTT), and CPU utilization. The results from the testing showed that the data throughput values in the open system were higher comparable to secured systems. However, the results demonstrated that the performance of throughput degraded while security protocols were enabled. Similarly, RTT values were also increased after enabling the security protocols. However, the WPA protocol showed different behaviour towards RTT with best performance and less round trip time. In the case of CPU utilization, the experimental results showed that IPv6 outperformed IPv4 for CPU utilization with throughput and RTT. The research results showed that among the three security protocols tested; WEP, WPA, and WPA2, the WPA protocol has the best results for network performance except for data throughput. In the case of IP protocols, IPv6 has better performance compared to IPv4 in 802.11ac, whereas UDP and TCP protocol does not have significant influences over network performance for 802.11ac. Based on these results, it is concluded that the iii WPA with the UDP protocol under IPv6 is the best possible configuration to have the best performance of 802.11ac under security protocols enabled.