ATM networks can be extended to wireless networks by attaching wireless base stations to ATM networks, which allows mobile users roam with little restriction. Due to the physical limitation, handovers become unavoidable when mobiles move from one area to another. As ATM networks are connection-oriented, connections have to be rerouted if a mobile device is moving out its current cell. To have seamless communication, the handover process must be performed with small delay, minimal cell loss and no change in cell sequence. In this paper, we propose an architecture to link ATM network to wireless networks. The proposed architecture is built on a hierarchical structure that groups cells into clusters. Different handover protocols are used, depending on handovers is in the same cluster or between clusters. In addition, the protocols take appropriate actions based on the type of communications. The performance of this protocol is superior to the existing solutions in terms of speed and resource consumption.