eable overhead in terms of data bandwidth taken up by routing information messages. One approach to this problem, the biologically inspired AntHocNet, is described in the Section "Wireless Mesh Network Routing, p. 345". Chapter Three Internet Point of Presence Access points routers devices Wired connection Peer to peer connection Network connection Device to network connection Figure 3-8: Mesh Network Topology The multiplicity of paths in a mesh network has a similar impact on total network throughput as the multiple paths shown in Figures 3-4 and 3-7 for the case of wired network switches and sectorised wireless networks. Mesh network capacity will grow as the number of nodes, and therefore the number of usable alternative paths, grow, SO that capacity can be increased simply by adding more nodes to the mesh. As well as the problem of efficiently gathering and updating routing information, mesh networks face several additional technical challenges such as: Wireless link reliability - a packet error rate that may be tolerable over a single hop in an hub and spokes configuration will quickly compound over multiple hops, limiting the size to which a mesh can grow and remain effective. Seamless roaming - seamless connection and reconnection of moving nodes has not been a requirement in most wireless network standards, although 802.11 Task Groups TGr and TGs are addressing this. Security - how to authenticate users in a network with no stable infrastructure? From a practical standpoint, the self-configuring, self-optimising and self-healing characteristics of mesh networks eliminate many of the Wireless Network Physical Architecture management and maintenance tasks associated with large-scale wireless network deployments. ZigBee (Section "ZigBee (IEEE 802.15.4), p. 273") is one standard which explicitly supports mesh networks and the IEEE 802.11 Task Group TGs is in the process of developing a standard which addresses WLAN mesh networks. Two industry bodies have already been established to promote 802.11s mesh propos