Case Study: Microsoft: the world's largest WLAN

Just off State Route 520 in Redmond, Washington, you'll find Microsoft's headquarters. To be sure, it's not the typical software vendor's corporate address - the beige building found in today's suburban office park never too far from a strip mall.

Rather, Microsoft's HQ looks and feels more like a huge university with dozens and dozens of buildings where some 30,000 or so workers take up millions of square feet. In fact, in the Puget Sound area alone, Microsoft has more than 35,000 employees working at 113 sites covering more than 11 million square feet of office space. (Worldwide, the company has nearly 80,000 employees at 565 sites covering 24 million square feet.)

But it is, actually, what you cannot see at the Redmond campus and all of the other Microsoft offices that's even more remarkable than the totality of its physical operations: the wireless local area networks (WLANs) that blanket nearly every square foot.
To all employees the Wi-Fi network in Redmond looks and acts no differently than the Wi-Fi network set up in any other Microsoft office. "It's the same standards, the same connectivity, which makes it seamless for somebody traveling to Redmond, or to our offices in Tokyo, London or New York," says Jim DuBois, general manager of information security and infrastructure services. "They walk into the building, and it automatically connects like the way it does here."

All Microsoft employees also see the same security measures, even though most of it is running in the background. "Today, our end users don't even realise that's happening in the background when we provision new machines that are connected to the network," he says.

Security is even more complicated because, as DuBois points out, when you add in the number of assorted vendors and contractors using the wireless network, the number of provisioned accounts on Microsoft's Active Directory reaches 145,000. To connect all those users, Microsoft uses a total of 11,000 access points in all of its buildings.

As to its claim to fame of being the world's largest Wi-Fi network, DuBois says, "We haven't found anyone that has a bigger private wireless network."

A History of Wireless Access

In December 1999, Microsoft started formally rolling out IEEE 802.11b wireless networks for employee use and as an alternative to wireline-attached laptops on the Redmond campus. "Though we had it in pockets even before that," DuBois says. The campus started out with 2,800 wireless access points.

[Some more details from Techworld's archives: Microsoft initially used standalone Cisco access points, and started to link them using Cisco's WLSE scheme, but gained experience of Aruba from kit used for security monitoring, and eventually switched from Cisco to Aruba - Editor]