IEEE 802.11a Standard
802.11a, which has just started to ship, is much faster than 802.11b, with a 54Mbps maximum data rate (actually increased to 72Mbps or 108Mbps in a non-standard double-speed mode depending on the chipset vendor and component manufacturer). 802.11a (and its recently announced interoperability standard called Wi-Fi5) operates in the 5GHz frequency range and allows eight simultaneous channels. One big advantage to 802.11a is that it isn't subject to interference from Bluetooth or any of the other 2.4GHz frequency denizens. One big disadvantage is that it is not directly compatible with 802.11b, and requires new bridging products that can support both types of networks--although if you don't mind spending the money for access points for both 11a and 11b, you can plug them into hubs or better yet, switches on your network and they'll work just fine. Other clear disadvantages are that 802.11a is only available in half the bandwidth in Japan (for a maximum of four channels), and it isn't approved for use in Europe, where HiperLAN2 is the standard. Another IEEE group, 802.11h, is working on technologies that will tweak 802.11a to work around some of the 5GHz channels used by military in Europe. Like 802.11b, 802.11a has no provisions to optimize voice or multimedia content.