Introducing IEEE 802.11r

The new amendment to the 802.11 standard supports VoWi-Fi handoff between access points.

On July 15^th of this year, without much fanfare, the IEEE published the final specification for IEEE 802.11r-2008, also known as Fast Basic Service Set Transition, an amendment to the 802.11 standard that supports fast handoff between access points—specifically in order to enable VoIP roaming on a Wi-Fi network with 802.1X authentication.

Kelly Davis-Felner, senior director for the Wi-Fi Alliance, says the key strength of the new standard lies in the fact that it brings the handoff time between APs down to below the 50 millisecond mark, which, she says, “is widely accepted as the point at which it would be perceptible on a voice call.”

One significant benefit of the arrival of 802.11r as a standard, Davis-Felner says, will be the ability of corporate networks to use multiple vendors. “Industry standards benefits everybody—big guys, small guys and end users—but perhaps the biggest beneficiary is going to be the IT manager who’s trying to a build a Wi-Fi network that people can use with their handsets,” she says.

And Davis-Felner says 802.11r meshes well with the Wi-Fi Alliance’s planned Voice-Enterprise certification program, scheduled to begin next year as an enhancement to the Voice-Personal certification. “It adds elements of r—it adds the security/authentication component of it, which you don’t see in a home environment,” she says.

An easier sell

Stan Schatt, vice president and research director for wireless connectivity at ABI Research, says 802.11r inevitably faced fewer battles in its approval process than a more fundamental—and therefore more contentious—standard, such as 802.11n. “When you’re talking about something like n, vendors are fighting to retain their time-to-market advantage, whereas r is basic middleware… so you’re not making any fundamental changes in your manufacturing process,” he says.

Schatt says the new standard should be a boon both for smaller fixed-mobile convergence (F/MC) players and for smaller Wi-Fi equipment vendors. “It means that customers will be able to mix and match a little more than they have in the past,” he says. “Whenever you have standards, it kind of levels the playing field, because you don’t have to invest so much in programming and R&D.”

Key markets for voice over Wi-Fi (VoWi-Fi), Schatt says, include hospitals, manufacturing facilities—and educational institutions. “In higher education, you’ve got faculty and administrators who are constantly moving around from building to building for classes, and this allows them to be in constant contact,” he says.

And the next big step for the VoWi-Fi market, Schatt says, will be to provide support for 802.11n phones—which he doesn’t expect to see for another few years. “In three years, n is going to dominate the market so thoroughly that economies of scale will certainly drive the price down—and the battery life technology will be much better then, too,” he says.

Increasing security

Geri Mitchell-Brown, director of technical business development for Polycom and chair of the Wi-Fi Alliance’s VoWi-Fi marketing task group, says 802.11r’s real strength lies in its support for 802.1X security. “If you’re going to do WPA2-Enterprise, which requires 802.1X authentication, in a client device that has a delay-sensitive application, you need some kind of fast roaming mechanism—and that’s what 802.11r delivers,” she says.

The point, Mitchell-Brown says, is that enabling a higher level of security in devices that support real-time applications is key to making the wireless LAN equivalent to the wired LAN. “If you can offer the same level of security for any application, then you’re moving towards that ability to have the all-wireless office… and 802.11r is a key component of that,” she says.

Still, Mitchell-Brown says Polycom won’t likely implement 802.11r until Voice-Enterprise is rolled out and supported by WLAN manufacturers. “Our timeframes are based on support in the wireless LAN, which I expect to be driven by the Voice-Enterprise certification program in late ’09… the launch of the certification program by the Wi-Fi Alliance will be the driving factor for vendors to implement it,” she says.

At the same time, the Wi-Fi Alliance’s Davis-Felner says this is the right time for the arrival of a standard like 802.11r. “Most analysts are saying that handsets are going to be about a third of the Wi-Fi market in a couple of years—and this is a major enabler of that,” she says. “This really brings that voice over Wi-Fi experience to a cellular-like experience.”

• For more on IEEE standards, read "802.11g Approved by IEEE Working Group," "IEEE Advances Wireless MAN Standard," and "IEEE 802.11g-reen lighted After Task Group Battle."
• For more on Voice over Wi-Fi (VoWi-Fi), visit our VoIP section and read "Mobile Unified Communications: You Can Take It with You," "The Inevitability of VoWi-Fi," and "New VoWi-Fi Certification Program Ensures Interoperability and Performance."
• For more on WPA-Enterprise, read our series, "WPA-Enterprise for Small Businesses."
• For more on fixed/mobile convergence, read "Wi-Fi/Cellular Convergence Takes Center Stage," "The Battle for the Home Zone," and "UMA . . . and beyond."