The .NET framework architecture is mainly depicted as follows:

The architecture shows the following:

-.NET framework (CLR +BCLs)

-Operating System, in which the .NET framework and Visual Studio development tool can be installed . The OS can be either Windows or any other such as LINUX , UNIX, Solaris etc. for installing .NET framework since it is platform independent. But to install and use Visual Studio we need only Windows platform since Visual Studio tool is platform dependent.

-Technologies that subscribe to .NET Runtime
-WPF (Windows Presentation Foundation), WCF(Windows Communication Foundation), WF 
(Windows Workflow), CardSpace .(.NET framework 3.0 additions)
-LINQ (Language Integrated Query), ADO.NET Entity framework (.NET framework 3.5 additions).
   
-Languages that subscribe to .NET Runtime (C#, J#, VB etc.) i.e. those languages that are according to CLS (Common Language Specifications)