W3C: "SOAP is a lightweight protocol for exchange of information in a decentralized, distributed environment. It is an XML based protocol that consists of three parts: an envelope that defines a framework for describing what is in a message and how to process it, a set of encoding rules for expressing instances of application-defined datatypes, and a convention for representing remote procedure calls and responses."
The structure of a SOAP message is:
[SOAP message (XML document) [SOAP envelope [SOAP header? element* ] [SOAP body (element* | Fault)? ] ] ]
This chapter contains the following sections: