Seamless Handoff Support in Wireless Mesh Networks

Supporting user mobility is an important requirement in design and deployment of a wireless mesh network. This paper presents network level mechanisms for supporting seamless handoff of user between access points in the mesh network. Our goal is to minimize the packet loss incurred in the process of handoff. In realizing the goals, we propose two data caching mechanisms: En-route and Promiscuous. The caching mechanisms are based on caching data at nodes on the route of flow (En-route) and at nodes that can overhear the packet transmission in promiscuous mode (Promiscuous). Both the above caching mechanism incurs no extra network overhead. We evaluate the benefits of the proposed caching mechanisms for real-time application such as VoIP. Our result shows that caching improves the data availability and results in reducing the packet lost and average packet delay. Furthermore, for VoIP application, the quality metric given by R-score is significantly improved by employing the proposed caching mechanisms