Not all enterprise IT and networking staffs can boast the same level of technical proficiency as Microsoft's. But, hey, somebody with plenty of resources has to pioneer new technologies to help iron out the kinks for the rest of us. And when it comes to wireless LANs, Microsoft is one of the few companies that has taken the plunge enterprisewide. Today, Microsoft has the benefit of nearly three years' experience with a global WLAN deployment under its belt to share.So why did Microsoft deploy WLANs, and what has been the upshot? Don Berry, the senior network engineer at Microsoft who began designing the wireless network in late 1999 and deploying it in 2000, relates his company's story."The initial business driver was that we needed an environment for developing wireless-aware operating systems and applications," Berry explains. Now, however, Berry estimates that each of Microsoft's wireless users - whether knowledge workers or developers - gain at least an hour of productivity per day.\u00a0"We've had senior vice presidents say, 'wireless saves me 1.5 hours per day.' It doesn't take too many of those gains [at senior-executive salaries] to quickly realize big returns."Today, Berry estimates, 14 million square feet of Microsoft workspace have WLAN coverage, delivered by about 4,000 Cisco Aironet access points (AP) across 70 countries. Current deployment costs, he estimates, are about 50 to 60 cents per square foot in the U.S. and about $1 outside the U.S.A couple of interesting informational nuggets:* Back in 1999, the only 802.11b vendors shipping products were Aironet Wireless Communications (which was purchased shortly thereafter by Cisco) and Lucent. Berry says Microsoft chose Aironet for the strength of the management capabilities in the company's 340 and 350 series APs.* Microsoft is considering the Cisco Aironet 1200 Series AP as a replacement when the 350 is discontinued, but only for 802.11b connectivity at this juncture. Surprisingly, the percentage of bandwidth utilized, Berry says, remains in the single digits. "We're not looking for an infrastructure upgrade [to 802.11a] until 2005," he says.What does Berry think about the emergence of WLAN switches and thin APs?\u00a0 "There's merit to not having to upgrade APs with more processing and memory," he observes. "But for small sites, a thin-only model wouldn't work. A mix of fat and thin APs, but with the same feature sets, will likely be the model."Next time: Berry describes the company's design goals and some deployment specifics.