This paper proposes a traffic control scheme to support real-time traffic over the IEEE 802.11 wireless LAN systems that do not have QoS support functionality. The main features of the proposed scheme are bandwidth control for each flow and load balancing between access points by using information of data link, network and transport layers. The proposed scheme was implemented on a Linux machine which is called traffic controller. The traffic controller connects a high capacity backbone network and an access network and the access points of wireless LAN are attached to the access network. We evaluated the performance of the proposed traffic controller and confirmed that the communication quality of real-time traffic would be greatly improved by using this technique.