Application Server Foundation is the group of technologies that are installed by default when you install the Application Server role. Essentially, Application Server Foundation is Microsoft .NET Framework 3.0.

Windows Server 2008 includes .NET Framework 2.0, regardless of any server role that is installed. .NET Framework 2.0 contains the Common Language Runtime (CLR), which provides a code-execution environment that promotes safe execution of code, simplified code deployment, and support for interoperability of multiple languages. Installing Application Server Foundation adds .NET Framework 3.0 features to the baseline .NET Framework 2.0. For more information about .NET Framework 3.0, see .NET Framework Developer Center (

Application Server Foundation Components

The following are the key components of Application Server Foundation:

  • Windows Communication Foundation (WCF)

  • Windows Workflow Foundation (WF)

  • Windows Presentation Foundation (WPF)

Each component is installed as a set of libraries and .NET assemblies.

For server-based applications, the most valuable components of Application Server Foundation are WCF and WF. WPF is used primarily in client-based applications.


WCF is the Microsoft unified programming model for building applications that use Web services to communicate with each other. These applications are also known as service-oriented applications. Developers can use WCF to build secure, reliable, transacted applications that integrate across platforms and interoperate with existing systems and applications. For more information about WCF, see What is Windows Communication Foundation? (


WF is the programming model and engine for building workflow-enabled applications quickly on Windows Server 2008. WF includes support for both system workflow and human workflow across a variety of scenarios, including the following:

  • Workflow within line-of-business (LOB) applications

  • User interface (UI) page flow

  • Document-centric workflow

  • Human workflow

  • Composite workflow for service-oriented applications

  • Business-rule-driven workflow

  • Workflow for systems management


WPF provides a unified programming model for building rich Windows smart-client applications. As a component of .NET Framework 3.0, WPF is installed as a part of Application Server Foundation. However, it is not commonly used in server-based applications.

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