Wi-Fi Alliance takes grid place, revs engine in race to 802.11ac

The Wi-Fi Alliance is now formally certifying devices conforming to 802.11ac, the 5GHz wireless standard capable of delivering 1Gb/sec, only a year after manufacturers started shipping kit.

The first 802.11ac router hit the shelves back in May 2012, but it wasn't approved by the Wi-Fi Alliance – which, quaintly, still thinks buyers want to see its logo on the box.

From today, though, 802.11ac devices can bear the coveted logo, thanks to a formal testing and approval process which kicked off last week.

It's not unusual for boxes to hit the shelves before interoperability testing has started; pre-approval kit has always proceeded, and sometimes driven, technical standards. The IEEE is responsible for writing those standards, and naming them ("ac" is no reference to 802.11a, it's just the 29th variation), the 'Alliance just enforces compliance and compatibility though testing.

Testing is carried out at approved centres and involves interacting with eight reference designs, to ensure implementations play nicely together and don't upset previous versions. The 802.11ac specification mandates the broader 5GHz band, as opposed to the increasingly crowded 2.4GHz band, and all compatible devices must have the ability to use 80MHz channels to achieve the 1Gb/sec headline speed.

This does require country-specific routers, however, as the 5GHz spectral map is far from global.

Routers conforming to 802.11ac are country specific, with the knowledge of which bands are available in that territory. When a device connects, a spectral map is forwarded using the 802.11d process, so client and server both know where they are and how loud they can shout.

Change the country code of the router and more bandwidth might become available - but that would obviously be illegal.

With devices already on the shelves one might question the value of a Wi-Fi Alliance blessing, but much of the success of wireless Ethernet is down to the interoperability it offers.

Consumer perception is that Wi-Fi just works, and that perception shifts a lot of boxes, so a formal approval process is probably almost as important as the details of the standard against which new devices are tested. ®