RealTime IT News

802.11e Spec Finalized

The IEEE 802.11 Working Group put the finishing touches on the specification called 802.11e last month. The standard will enhance the Media Access Control (MAC) layer of 802.11 chips to handle quality of service (QoS) — in other words, it prioritizes traffic such as video, audio and voice on Wi-Fi networks, delivering better performance for VoIP and multimedia applications.

SpectraLink, a major player in the voice over IP over Wi-Fi (VoWi-Fi) space, welcomes the new spec but says that things are far from the point where vendors can take advantage of what 802.11e is supposed to deliver. That will come more when the Wi-Fi Alliance steps in with their own take on 802.11e.

"The Alliance has shown the way vendors and markets get together, how we want to really implement things — rather than the IEEE take, which is very inclusive for stuff in the standard, stuff that may or may not be implemented," says Ben Guderian, director of marketing at SpectraLink.

The Alliance has been performing non-mandatory testing for a subset of the 802.11e's draft specification, which it calls WMM (Wi-Fi Multimedia), since September of 2004. That approach is roughly analogous to how the Alliance started Wi-Fi Protected Access (WPA) as a subset of the 802.11i spec for security. Once 11i was finalized, the Alliance updated its test to WPA2.

Guderian says that 802.11e's QoS offerings will be very important to future WLANs. His company has long offered a proprietary protocol called SVP (SpectraLink Voice Priority), something he says may not be needed eventually because 11e will take care of the QoS of voice traffic.

"It helps us in the long term," says Guderian. "It's one thing that we don't have to explain — everyone would have the same standard." He says this will be even more important as enterprise customers want to use WLANs for voice and multimedia data. SVP was designed to support voice only.

Does 802.11e do enough for video? Bill Kish, the CTO at Ruckus Wireless (formerly Video54) doesn't think so, at least not in the consumer market. That's where wireless video is likely to make the biggest splash, at least initially.

"11e is solving a portion of the problem of QoS," says Kish. "It provides basic hardware prioritization for differentiation of certain classes of service. That's part of the problem, but it's also the easier problem to solve."

Ruckus believes the more pressing problem for consumer video and voice over wireless is link stabilization — an area improved more by the (not-even-in-draft-stage) 802.11n specification, or the technology Ruckus sells called BeamFlex, which uses a mix of seven smart antennas and 127 antenna signals to get around and through obstacles.  

In the end, Kish says, there's always room for proprietary technologies that don't impact interoperability: "I think at the end of the day none of the standards will completely address the problem... there's specs that go a long way toward helping, but there's detailed design issues that will always impact the performance of the end product."