Component Model

.NET uses assemblies which are compiled and versioned collections of code and metadata that form an atomic functional unit.
An assembly contains the code, the version number, a list of all the other assemblies (with version number and public keys) it requires to run, and a description of the interface it provides.
Assemblies are generated for you by VS.
No IDL is needed. The interface is generated automatically (as with RMI, but supporting many languages).
The code in these assemblies runs in the common language runtime.