Microsoft comes out on top of the NAC heap in an evaluation of 10 vendors that was published recently by Forrester Research. (Compare NAC products)

The result is interesting because it’s not based on how many units were sold or performance tests but rather on evaluation of how well the products would meet the challenges of a set of real-world deployment situations.

These included controlling access based on role and identity of the user, how well the products handled guest access, how well they worked in wireless and virtual-desktop environments, how well they support and make use of existing infrastructure, and how well they restrict application access, among others.

Another large chunk of ratings went to the vendors’ strategies for long-term development of their products. So Microsoft benefited from its support of other Microsoft products such as Active Directory and System Center Configuration Manager. It also benefited from its large body of partners whose NAC gear interoperates with Microsoft’s network access protection (NAP) the name for its flavor of NAC.

Cisco and Juniper round out the top three scorers in the Forrester study, but a much smaller vendor, Bradford Networks, ranked in the same overall category - leaders. Forrester credits ease of deployment, support for multiple enforcement options and the ability to scale in large deployments for the high ranking.

The study says that other vendors use a similar architecture to that used by Bradford, but “Bradford has the best all-round support for third-party infrastructure,” meaning it interoperates better with more products by other vendors. Forrester also liked the company’s roadmap.

For more about the report entitled “Forrester Wave: Network Access Control: Q3 2008” click here.

Tim Greene is senior editor at Network World.