With the 802.11n standard officially ratified by the IEEE, the Wi-Fi Alliance has lived up to its promise by grandfathering all Wi-Fi Certified 802.11n Draft 2.0-labeled products to its new certification, called Wi-Fi Certified N, while simultaneously trying to reduce some of confusion that will arise from the dizzying array of feature configurations that comprise 802.11n.
When the Wi-Fi Alliance announced earlier this summer that the 802.11n Draft
2.0 certification program would be forward-compatible with the full 802.11n
standard upon formal ratification of the latter, wireless LAN
implementers finally had concrete assurance that they could move forward with
802.11n deployment plans without fear of any interoperability problems caused
by late changes to the standard.
Now, with the 802.11n standard officially ratified by the IEEE, the Wi-Fi
Alliance has lived up to its promise by grandfathering all Wi-Fi Certified
802.11n Draft 2.0-labeled products to its new certification, called Wi-Fi
Certified N, while simultaneously trying to reduce some of confusion that will
arise from the dizzying array of feature configurations that make up 802.11n.
The Wi-Fi Alliance has therefore ensured that hardware manufacturers would
not need to resubmit their products for testing to display the new
certification. Instead, companies with Draft 2.0-certified products need only
change the certification logo on the packaging and other marketing
materials. And customers who bought enterprise-grade Draft 2.0-certified
products from companies like Aerohive, Aruba, BelAir,
BlueSocket, Cisco, Enterasys/Siemens, Extreme Networks, Extricom, Intel, Meru,
Motorola, Trapeze and Xirrus won't need to do anything to ensure compliance
with the new certification program.
That's not to say there's nothing different between the Draft 2.0
certification and the Wi-Fi Certified N certification. For instance, one
change that caught my eye was a slightly different approach to Wi-Fi clients
that could make a wider variety of SISO (Single Input Single Output) client
devices with lowered power demands eligible for Wi-Fi certification.
Specifically, in the Draft 2.0 testing, access points and clients needed to be
able to both transmit and receive at least two spatial streams. While this
requirement remains the same in the new program for access points, client
devices are now required to transmit and receive only a single spatial stream.
This slight modification could help hasten the delivery of 802.11n radios to
certain business-class devices-tablets or netbooks come to mind-that would
greatly benefit from a faster WLAN implementation without taking an undue hit
on battery performance.
Handheld devices-such as voice over Wi-Fi phones and smartphones-were
exempted from this requirement in the Draft 2.0 certification program, but if
increasingly optimized SISO radios are developed for other devices, perhaps the
price and the power draw will fall to a point where hardware makers can add
802.11n to handhelds with negligible downsides.
With Wi-Fi Certified N, the Wi-Fi Alliance also expanded the scope of
optional features it will test for as part of the certification process,
creating new taglines meant to highlight performance levels over the basic
Certified N requirements.
For instance, to achieve the new "Dual-Stream N" tagline, hardware makers
need to pass tests of optional features like A-MPDU (Aggregated MAC
Protocol Data Unit) transmit and STBC (Space-Time Block Coding) transmit, as
well as 40MHz channels (but only in the 5GHz band) with at least a 1 (transmit)
by 2 (receive) MIMO configuration. While access points and clients are
required to be able to receive A-MPDU aggregated frames (which can be used to
reduce the protocol transmission overhead on a wireless network), it is
optional that devices be able to transmit these frames (which can be used to
reduce the protocol transmission overhead on a wireless network).
A second tagline, called "Multi-Stream N," highlights even greater
performance potential, requiring at least a 3 by 3 MIMO configuration in
addition to the requirements needed for "Dual-Stream N."
In another commendable move, the Wi-Fi Alliance is trying to reduce some of
the confusion surrounding dual-band configurations with a new matrix appearing
underneath the logo and tagline (if the hardware maker wants it there, of
course). The matrix is designed to spell out what configurations were
tested in which band, and provide some information about the nature of the dual-band
implementation in question. In this way, buyers may be able to more
effectively determine whether a marketed dual-band device has multiple radios
or whether a single radio is simply frequency selectable.
Senior Analyst Andrew Garcia can be reached at firstname.lastname@example.org.