Multi-Channel Multi-Interface Wireless Mesh Testbed

Current day wireless technologies, such as 802.11a, support multiple non-overlapping channels. Multiple channels can be potentially used to increase network capacity by simultaneously communicating across different channels. In infrastructure based networks, multiple channels have been utilized by placing adjacent access points on different channels, thereby promoting simultaneous use of the channels. However, in adhoc (infrastructure-less) networks, a single channel is typically used for enabling adjacent nodes to directly communicate with each other. Presently, most nodes are typically equipped with only one wireless interface. Recently, with reducing hardware costs, it is possible to equip nodes with more than one wireless interface. Nevertheless, the number of interfaces at each node is expected to be smaller than the number of channels. Our research [1]– [4] has shown that even in this scenario, network capacity can be significantly improved by using suitable protocols. However, implementing these protocols in realistic testbeds is difficult, as the underlying operating system may not have the requisite architecture to support many of the features required by the protocols. For example, protocols may require interfaces to be switched among channels, but there is no architectural support for switching channels without modifying existing user applications. In this paper, we briefly discuss the challenges in supporting a multi-interface, multichannel wireless network. We then present our architecture for implementing such a network, and describe a prototype implementation on a Linux testbed.