Programmers have long been able to have one program to call routines provided by another program that is running either on the local computer or some other computer on the same network. The omnipresent Internet extended this capability to new and greater levels, allowing a client program to call service routines provided by a server that could be physically on the other side of the world.
New web technologies such as Simple Object Access Protocol (SOAP) made it easy enough to build web services for use by other programs over the Internet. This gave rise to a whole new type of application that implements a significant amount of its functionality by calling services. Because these programs focus on the use of services, this design is called service-oriented architecture (SOA).
Windows Communication Foundation (WCF) is a set of classes and tools in .NET Framework 3.0 that make it easier to build SOA applications. It includes attribute classes that let you easily mark pieces of a server application to publish services for use by clients. It also includes tools to automatically generate the Visual Basic code you need to use or consume the services.
WCF is quite large and very flexible. It gives you the ability to write secure, reliable services that support transactions and can use a variety of transport methods. For example, clients and services can communicate using HTTP or TCP network protocols, or named pipes or message queues on the local ...