2.1.2RPC and EDI
XML messaging, and therefore SOAP, has two related applications: RPC and EDI. Remote
Procedure Call (RPC) is the basis of distributed computing, the way for one program to make
a procedure (or function, or method, call it what you will) call on another, passing arguments
and receiving return values. Electronic Document Interchange (EDI) is basis of automated
business transactions, defining a standard format and interpretation of financial and
commercial documents and messages.
If you use SOAP for EDI (known as "document-style" SOAP), then the XML will be a
purchase order, tax refund, or similar document. If you use SOAP for RPC (known,
unsurprisingly, as "RPC-style" SOAP) then the XML will be a representation of parameter or
return values
REF: programming web service with soap [oreilly] chapter 2.1.2
