Controller-based, pervasive wireless LANs are quickly become a standard feature of enterprise networks, according to a new study by BT North America.

And nearly one-third of enterprises are migrating to the high-throughput draft 802.11n WLAN standard within the next 12 months. The study's authors say that rate of adoption for a not-yet-ratified standard is unprecedented, indicating that 11n benefits are urgently needed by a significant number of enterprise sites. But half of the respondents still say there's no rush, and no plans to make that move.

The Web-based survey was completed by IT professionals from 226 companies. Forty-three percent of those companies had 1,000 or less IT employees; 28% had 1,000 to10,000; and one-quarter had more than 10,000. (Compare enterprise WLAN products).

Thirty-nine percent of the survey respondents said they have controller-based WLAN architectures, and 22% more are either actively migrating to that or plan to. The trend is most pronounced in larger companies, according to Rick Blum, director of strategic marketing for the BT consulting group, and author of the study.

But controller solutions can become very expensive for companies with lots of branch offices or remote locations. One start-up, Aerohive, has eliminated the controller as a separate box: It's offering a distributed WLAN architecture that still permits centralized management. A 102-store 7-Eleven chain in Oklahoma recently deployed the Aerohive gear.

The main enterprise driver for WLANs is making employees mobile, increasing collaboration and/or improving productivity, says Greg Taylor, practice lead for BT's WLAN consulting practice. Sixty-one percent of the sample listed these as "very important."

Taylor says there is little formally published literature on improved efficiencies, but some create internal studies in an attempt to document improvements. But measuring in hard dollars is rare, he says. "It's more about the whole feature set associated with wireless LANs," he says.

That's often coupled with a desire to deploy a secure wireless infrastructure to pre-empt unauthorized and vulnerable rogue WLAN deployments within the enterprise.

But those "softer" criteria also make it likely that WLAN expansions or upgrades may be sidelined in favor of higher priority projects, such as data center virtualization, which demonstrate hard-dollar cost justification, both men agreed.