The backbone of Windows Identity Foundation is the "Identity Bus" model. The Identity Bus is designed to provide authentication and authorization claims via Secure Token Services (STS). However, in a typical Windows Identity Foundation deployment, a separate STS is required to extract authentication and authorization information from each enterprise repository.
With the integration of the Virtual Identity Server, Windows Identity Foundation deployments can be simplified. Using a custom Secure Token Service which leverages the Virtual Identity Server, organizations can deploy one enterprise Secure Token Service with the Virtual Identity Server providing a single real-time joined view of the multiple directories, forests and other data stores for authentication and authorization.
By reducing the number of Secure Token Services that are required, the Virtual Identity Server enables rapid deployment of claims-based applications within the Windows Identity Foundation framework.
One can think of the Virtual Identity Server / Windows Identity Foundation integration as a "greener", more fuel efficient Identity Bus. A bus that reduces the impact on enterprise resources.
In addition, the Virtual Identity Server’s built-in support of dynamic and auto groups adds new, exciting authorization capabilities previous not available in Microsoft’s Windows Identity Foundation alone.
Combing the power of Microsoft’s Windows Identity Foundation and the Virtual Identity Server provides organizations with the tools needed to develop and deploy secure, claims-based application and cloud services.