A complete IT security rethink is needed for the age of cloud computing, according to Cisco System's vice president and general manager of Security Tom Gillis.

On Tuesday Gillis spoke at the Mobilize Conference in San Francisco. "In a world where your endpoint and your servers are now becoming ... you're losing control of your physical assets, where is that container and those policies, and where is that going to reside? In a network that no longer has a clearly defined beginning and end, where am I going to put those hooks and levers and controls? I have to put them in the fabric of the network itself."

Gillis warns that the transition to new security architecture may take five or ten years.

"We need to not just sort of make incremental improvements to that which exists today, to repackage that firewall you were talking about. We have to reimagine it. We have to step back and look at, what problem am I trying to solve?"

As consumer devices show up in the office, Gillis says workplaces need to build a security system that can handle them—from tablets to smart phones and whatever’s next.

Letting employees chose devices works for cisco, which started issuing macs three years ago.

"Here's what's interesting. We have about 50,000 employees. Of that population base, we've got about 10,000 Mac users. And the price of using a Mac is that it's self-supported. So after running this program for three years, the experience we have is that our cost has been reduced by 25 percent. We surveyed our employees, and end-user satisfaction is up 200 percent."

From the mission bay conference centre in San Francisco.