The Broadband and Wireless Network (BWN) Lab at Georgia Institute of Technology has recently built a testbed of WMNs . The WMN, called BWN-Mesh, consists of 15 IEEE 802.11b/g based mesh routers, among which several of them are connected to the next generation Internet testbed (also available in the BWN Lab) as backhaul access to the Internet. The testbed consists of laptops and desktops equipped with IEEE 802.11b and IEEE 802.11g cards located in various rooms on the floor where the BWN Lab resides. By changing the topology of the network, experiments investigating the effects of inter-router distance, backhaul placement and clustering are performed along with mobility experiments using the laptops in the testbed. Moreover, experiments with existing protocols (i.e., TCP, AODV, and IEEE 802.11g as transport, routing, and MAC protocols) for BWN-Mesh testbed have demonstrated that these protocols do not perform well in terms of end-to-end delay and throughput in WMNs. Currently, the research is focused on adaptive protocols for transport layer, routing and MAC layers and their cross-layer design. These protocols are developed and evaluated on the BWN-Mesh testbed. The approaches being explored in the BWN lab are not merely limited to Wi-Fi mesh networks but also applicable for wireless sensor networks (WSNs) and wireless sensor and actor networks (WSANs). Thus, the BWN-Mesh testbed is integrated with the already existing BWN Sensor Network Testbed, which consists of MICA motes, with TinyOS distributed software operating system, and light, temperature, acoustic actuator, magnometer, and accelerometer sensors. In align with this effort, BWN Lab is also trying to integrate the current Wi-Fi mesh networks with other wireless networks such as WiMAX. Consequently, this integrated testbed will enable the design and evaluation of protocols applicable to heterogeneous wireless networks including WMNs, next generation Internet, WSNs, WSANs, and WiMAX.