The NAC market continues to evolve, including the necessary and sometimes painful process of consolidation.

That’s the neutral term used for businesses that sell products based on new technologies either going out of business because of competition or getting bought by other companies because they need the products in their own portfolios.

The initial frenzy of vendors trying to make a go of the new technology dies down and a reasonable balance between supply and demand takes hold, meaning some of the startups get weeded out.

This week Mirage Networks left the ranks of independent NAC vendors when it was bought by security managed service provider Trustwave – which is the happy way for a startup to be consolidated.

Trustwave plans to sell a managed NAC service based on Mirage gear. Longer-term, it plans to integrate Mirage’s software into Trustwave’s unified threat management device that it installs at customer sites and manages remotely. At least for now, the company will continue to sell Mirage gear to customers that want to own and manage NAC by themselves.

Other NAC vendors have disappeared under less pleasant circumstances. Caymas Systems went out of business for lack of funding and its NAC assets were bought up by Citrix. Lockdown Networks simply shut down operations. And Vernier Networks retired the name, regrouped and is back as Autonomic Networks making access-management and compliance software.

Expect more of this. Given the tough economy, the absorption of NAC into infrastructure and identity-management products, and the natural consolidation cycle that is due, it’s time for a shakeout that will leave only the strongest.

Tim Greene is senior editor at Network World.