In addition, because Microsoft has offices all around the globe and next to other companies (including competitors), the IT teams need to ensure that the wireless "bleed" is protected and secured. "We think we've solved this with our 802.1x infrastructure," Dubois says, "and that gives us the security that we need."

Microsoft also offers a wireless network for its guests that is kept separate from the corporate network. That's because "having a separate guest network is actually more secure than having your guest connect to your corporate network and be able to have access to anything there," DuBois says. "This really does give us the ability to provide Internet access to any of our guests without opening up any access to our corporate network."

As for the future of Microsoft's WLAN, DuBois reports that the company is piloting tests with products using the 802.11n standard, the next generation of wireless networking that will give users more bandwidth and greater speeds (up to 300Mbps) for streaming HD video, downloading and sending big files, and using voice applications over Wi-Fi networks. (That is, of course, when the standard is finally ratified. See "Deciding When to Upgrade to 802.11n" for more on this troubled standard.)

DuBois is excited about 802.11n's effect on unified communications applications at Microsoft. For example, employees who are talking on their smart phones will be able to switch back and forth between the cellular networks and Microsoft's wireless network, thus saving money on cell phone charges when employees are in the proximity of Microsoft wireless networks.

Eventually, everybody's desk phone will be a smart phone, DuBois says, "so that if anybody calls me, it'll be able to can find me in any one of our buildings or outside the buildings."

There are sure to be more people calling him: judging by the new construction at Microsoft's Redmond campus—six towering cranes dotted the skyline in mid-April and hard hats were everywhere—Microsoft will be adding more square footage to its sprawling campus. For DuBois, that will surely mean more wireless access points and more wireless network users.