Wi-Fi Needs To Be Over-Provisioned

The idea for Xirrus emerged when Gates attended a conference run by Intel Capital in 2003 which showcased a plethora of Wi-Fi startups, all making gadgets.

“I walked away absolutely convinced that the day would come when we would all be carrying multiple wi-fi devices.” And, with laptops, iPhones and iPads, that day is here.

But back in 2003, he says “not a single person spoke of infrastructure.” No one, he said, was addressing the issue of how to support the flood of mobile devices.

“The traditional approach back then was hanging up more access points,” he said. “But that wouldn’t scale.”

Aruba, Trapeze and Airespace (later bought by Cisco) were there, as was Symbol – now part of Motorola – but their approach was to “hang up more access points, and add centralised management,” Gates said.

Wi-Fi flying saucers?

Gates wanted to do it differently. Somewhat simplistically, he says he looked at the mobile industry, and decided to make Wi-Fi systems more like cell towers.

“Cell towers don’t have one or two radios, like Wi-Fi access points, they have a dozen, and that gives you longer reach,” he says. Like a cell tower, the Xirrus systems beam signals out in particular directions and have a longer reach, covering a broader area.

This means fewer access points are needed for a given building, and he claims a big saving on cables.”I can hang 80 percent fewer things in my building, but I end up with more radios, more capacity and more performance,” he says.

It also means his system can have more radios than the competition – especially important now that the 5GHz band, introduced by the 802.11n standard, allows many more channels.

The system also bears a resemblance to Ethernet provision, he says, and can replace Ethernet in many places. The intelligent switches that other vendors put on the network, are built into the Xirrus controllers attached to the ceiling, so there is more bandwidth available, says Gates.

This all results in big disk-like access/control units which combine radios and controllers. Gates makes use of the flying-saucer image in his advertising.

“If I funnel all that back to the controller I’ve got a massive bottleneck,” he says. Putting the switch inside the unit alongside the radios, means that network traffic is not needed.

Ethernet is normally rolled with twice as many ports as people, but “historically, Wi-Fi has gone in the opposite direction, with people trying to get the most number of users per radio. It is almost the exact opposite of Ethernet.”

Wi-Fi can’t replace Ethernet till you take it seriously

Unless Wi-Fi starts over-provisioning, it will never replace Ethernet in the edge of the network. The reason the traditional Wi-Fi vendors have failed to do this is obvious, he says, pointing out that Ethernet is currently a $20 billion market, while Wi-Fi is only $2 billion.

Why should Cisco replace such a profitable market with a smaller one, by encouraging users to replace Ethernet with Wi-Fi, he asks.

However the big vendors play it, Gates reckons the sheer demand for Wi-Fi connectivity will force the other Wi-Fi vendors’ hands, he believes. “The centralised management controllers had their day in the sun.”