802.11n Access Points and Power over Ethernet: Key Considerations

As we have noted before, IEEE 802.1n is the only wireless-LAN (WLAN) technology that matters today. The outstanding improvements in rate, range, and price/performance now being seen in both residential/SOHO-class as well as enterprise class products, as demonstrated by our own testing, have previously led us to conclude that the time to install .11n is now and that waiting will only result in an investment in last year’s technology.

Truly conservative technology adopters will of course take comfort in delaying action until the ink is dry on the still-under-development IEEE 802.11n standard, but the evergrowing demand for network throughput and capacity, as well as the need to support greater time-bounded traffic, indicates to us that .11n is today a far better investment than the venerable .11g and .11a. And the existence of a widely-implemented interim .11n specification from the Wi-Fi Alliance simply drops the last real barrier to adoption. We sincerely doubt that the official standard will differ in any meaningful way from this spec, and, if it does, backwards compatibility is all but assured.

A key consideration in the adoption of .11n, however, is the need for gigabit-Ethernet service to interconnect access points (APs) and to make sure that wire doesn’t become a choke point for the capabilities of .11n. A further concern, and the subject of this Tech Note, is whether .11n APs can be powered via that Ethernet cable. It’s one thing to upgrade Ethernet switches, but quite another if that switch or the IEEE 802.3af-compliant power injectors being used can’t handle the power demands of a .11n AP.