WLAN (Wireless Local Area Networks) is becoming popular in all kinds of data communications. Providing Quality of Service (QoS) especially for bandwidth intense, delay sensitive realtime multimedia traffic over WLAN is a challenge. In most presented work about providing QoS in wireless, the QoS for realtime traffic is achieved at the cost of best effort traffic. This paper presents a cross-layer design to provide QoS to both realtime traffic and best effort traffic over 802.11e networks. The proposed mechanism considers co-design of the Application and MAC layers in 802.11e networks. An interface is designed to tune MAC layer parameters based on the information from application layer. Simulations and performance analysis show our proposed mechanism not only provides QoS to multimedia traffic but also lets non-realtime users receive the maximum possible throughput. Thus, a mixture of realtime and non-realtime users can be supported simultaneously.