Hidden in the announcements from Apple regarding new Intel-based Macs is the detail that they are now supporting the 802.11a wireless networking standard. Here are some of the details from TidBits:
802.11a was declared dead by Steve Jobs back in Jan. 2003 when he introduced AirPort Extreme, and it seemed rather dead at the time. The advantage of 802.11a is that it has no backwards compatible mode with the older, slower 802.11b standard.
802.11b and g work in the 2.4 GHz band, and 802.11b runs at a maximum of 11 Mbps of throughput, or a net of about 5 Mbps. 802.11g has a maximum 54 Mbps, or a net of about 20 to 30 Mbps depending on add-ons and other factors.
The reason that the lack of compatibility with 802.11b is an advantage is that a network that sports both b and g adapters has worse performance than a g-only or any 802.11a network. The older “b” devices bring down the whole network, reducing the amount of shared airtime available for faster transmission.
802.11a has emerged in corporations and universities as a preferred tool for deploying voice over IP (VoIP) whether for campus calling or Internet telephony (VoIP to a gateway out to the public switched telephone network).