Simple Object Access Protocol - A data format for exchange of information over a network. It is an XML based RPC protocol that consists of three parts:

1. an envelope that defines a framework for describing what is in a message and how to process it;
2. a set of encoding rules for expressing instances of application-defined data types, and
3. a convention for representing remote procedure calls and responses.
   

SOAP can potentially be used in combination with a variety of other protocols; however, the most popular binding and the only one defined by the standard describes how to use SOAP in combination with HTTP and HTTP Extension Framework.

SOAP is widely viewed as an alternative to existing REST mechanisms. One of SOAP's advantages is that it allows platform-locked applications and systems to communicate using the Web (a platform-independent medium).

Diagrammatically:

[img ALT=SOAPImage LONGDESC=http://www.creativyst.com/Doc/Articles/Mgt/PIC/Diagb02LongDesc.txt SRC=http://www.creativyst.com/Doc/Articles/Mgt/PIC/Diagb02.gif]

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More Information:

• http://www.w3.org/TR/SOAP/