Remote procedure calling (RPC) refers to the ability to invoke a method of an object that resides outside of the caller’s address space, as if it were local. Although RPC is an old term, dating back to the early days of networked computers, the concept of using XML as an RPC mechanism dates back to the early days of Web Services.

SOAP is not the only XML RPC mechanism; in fact, another mechanism, called XML-RPC, is arguably simpler and easier to use. However, this simplicity comes at the expense of flexibility. Although XML-RPC evolved from an early version of SOAP, Microsoft has chosen not to support XML-RPC directly in .NET. However, there is nothing to stop some enterprising developer from producing an XML-RPC framework for .NET.

As I said earlier, .NET supports two general methods of serialization. Which one you should choose depends on your needs.