In today's networking there are several attractive alternatives to both public telephony and leased lines. IEEE 802.11 WLAN and Voice over IP are the most deployed technologies suitable for real-time applications which are playing major role in the next generation communication networks. In recent years VoIP has caught the imagination of communications and computing industries. Key characteristics of 802.11 WLAN technologies are simplicity, flexibility, and cost-effectiveness. The freedom to roam while still maintaining connectivity has helped propel wireless networking to new heights. However, VoIP solutions don't provide efficient usage of network bandwidth and can cause congestion of networks very quickly. In this project performance of two bandwidth reduction techniques cRTP and Silence Suppression for voice traffic over IEEE 802.11 WLANs is evaluated using OPNET Simulator. All the simulation results show that if cRTP and SS are employed together, they can significantly improve the network efficiency.