Windows Communication Foundation (WCF) (http://msdn.microsoft.com/en-us/library/ms735119(v=vs.90).aspx) is Microsoft's unified programming model for building service-oriented applications.
As we have seen, WCF is not specific to web services, but it offers a more general purpose model. It uses high-level abstractions as its constructing elements:
Endpoints: These are sources or targets for the communication. They can be clients or services (modelling typical client-server architecture), and can have a unique address associated with them (URI format).
Protocols: The way in which data will travel from one endpoint to another.
Binding: This defines the protocols and parameters used by an endpoint.
Service: This refers to a set of functionality composed by operations.
Operations: Access methods to the functionality provided by services.
WCF offers several concrete implementations of these concepts...