"We have 1,500 clients who we talk about using NAC. The majority of those have been going down the appliance route. A lot of people look at framework and say, 'There are a lot of features that are valuable, but how do you put these together?'" Rice said.

In the end, Cisco may end up throwing the CTA client open source as a way to differentiate itself from Microsoft's NAP technology, which is integrated in the Vista operating system, said Zeus Kerravala, an analyst at Yankee.

"Cisco's wondering 'how do we differentiate our own client?' Allowing application developers to experiment with it is one way, and the best way to do that is open source," Kerravala said.

The stakes for Cisco are low as only a handful of its customers have committed to the CTA, Kerravala said.

Adam Hansen, security manager at the law firm Sonnenschein, Nath & Rosenthal, LLP said that, in the scheme of things, open sourcing the CTA client' -- or not -- was of little importance. However, Cisco might derive considerable value from opening other elements of NAC framework and making it easier for third-party vendors to plug into it.