own in Figure 3-1 is probably more common in wireless than in wired networks, since it can be found in a wide variety of different wireless situations, such as: peer-to-peer or ad-hoc Wi-Fi connections wireless MAN back-haul provision LAN wireless bridging Bluetooth Star Topologies in Wireless Networks In wireless networks the node at the centre of a star topology (Figure 3-5), whether it is a WiMAX base station, Wi-Fi access point, Bluetooth Master device or a ZigBee PAN coordinator, plays a similar role to the hub in a wired network. As described in Parts III to V, the different wireless Wireless Network Physical Architecture Figure 3-5: Star Topologies in Wireless Networks networking technologies require and enable a wide range of different functions to be performed by these central control nodes. The fundamentally different nature of the wireless medium means that the distinction between switching and non-switching hubs is generally not relevant for control nodes in wireless networks, since there is no direct wireless equivalent of a separate wire to each device. The wireless LAN switch or controller (Figure 3-6), described in the Section "Wireless LAN Switches or Controllers, p. 48", is a wired network device that switches data to the access point that is serving the addressed destination station of each packet. The exception to this general rule arises when base stations or access point devices are able to spatially separate individual stations or groups of stations using sector or array antennas. Figure 3-7 shows a wireless MAN example, with a switch serving four base station transmitters each using a 90° sector antenna. With this configuration, the overall wireless MAN throughput is multiplied by the number of transmitters, similar to the case of the wired switching hub shown in Figure 3-4. Access point switch Figure 3-6: A Tree Topology Using a Wireless Access Point Switch Sector antennas Switching hub Figure 3-7: Switched Star Wireless MAN Topology Wireless Network Physical Architecture In the wireless 