less networking in the coming years. This page intentionally left blank CHAPTER Leading Edge Wireless Networking Technologies In this chapter four key technologies are discussed that are currently under development and that will play a large role in shaping the future of wireless networking; Wireless mesh network routing Network independent roaming Gigabit wireless LANs Cognitive, or spectrum agile radio. While individually these are significant step-outs from existing technologies (for example, cognitive radio radically extends the 802.11h enhancements to 802.11a networks that were described in the Section "Spectrum Management at 5 GHz (802.11h), p. 160"), together they herald a not-too-distant future in which spectrum availability, propagation range and data bandwidth are no longer limiting factors for wireless network performance. Wireless Mesh Network Routing As briefly described in the Section "Mesh Networks, p. 43", wireless mesh networks or mobile ad-hoc networks (MANETs) offer some significant advantages for large-scale wireless networking, including; self-organising architecture, optimising routing and traffic distribution Chapter Fourteen self-healing ability to respond to broken or unreliable wireless links increasing network throughput as the density of devices increases. A major challenge faced in defining mesh networking standards is to design Data Link layer protocols that are able to achieve this flexibility without consuming an excessive amount of network bandwidth for routing and control messaging. Simple, low overhead approaches to this problem, such as making routing decisions based on RF signal strength or the minimum hop count from source to destination, do not perform well compared to routing algorithms that actively probe the mesh topology and make routing decisions based on the historical and predicted throughput of the available paths through the mesh. One intriguing approach being investigated for mesh network routing is inspired by the communication method that enables ants to converge