Implementation frameworks for IEEE 802.11s systems

The standardisation process of IEEE 802.11s requires some effort to be devoted to assess the effectiveness of the proposed solutions. Specifically, the path selection and forwarding facilities, embodied by the Hybrid Wireless Mesh Protocol (HWMP), are the major and most delicate components. A working prototype can be profitably used to experimentally evaluate such features, thus returning immediate and significant feedback. In this scenario, the paper offers a threefold contribution. First, we review the current 802.11s implementation efforts, such as the Open 802.11s and One Laptop Per Child projects, highlighting the pros and cons of each solution. Then, we describe a prototype IEEE 802.11s Mesh Access Point (MAP) we developed starting from common off-the-shelf hardware and software. The main innovation of this prototype is the support of both modes of operation of HWMP. Conversely to the other projects, which implement only the reactive mode, our device also supports the proactive mode, and runs it in the same way as suggested by the draft standard, thus becoming a more complete evaluation platform. As a final contribution, we provide some Simulation results to assess the behaviour of the mixed proactive-reactive mode, From this evaluation, we can confirm that employing the proactive algorithm can bring some benefits to the operation of the 802.11s network, even though a careful approach must be taken to avoid some drawbacks. (C) 2009 Elsevier B.V. All rights reserved.