WLAN IEEE 802.11 Networks should be designed primarily for capacity. In a typical infrastructure WLAN network, now it demands more devices to connect in single network since business-critical applications rely on a Wi-Fi network also the amount of data transmitted wirelessly has significantly increasing which includes voice calls made over Wi-Fi, HD video streaming through Wi-Fi, file access and storage space in the cloud etc. In our work, we have evaluated the performance of a typical WLAN network working on the principle of IEEE 802.11b. The scenarios have been figured and analyzed using HTTP & Email in DLL, PHY & TPL layers. The statistics calculated are link throughput and application throughput using NetSim simulator.