hesitation, Dave Winer shipped XML-RPC in 1998. The submitted Internet Draft did not reach RFC status and is therefore not considered a "web standard" as such. Version 1.1 of the specification was published as a W3C Note on 8 May 2000. Since version 1.1 did not reach W3C Recommendation status, it can not be considered a "web standard" either. Version 1.2 of the specification, however, became a W3C recommendation on June 24, 2003. The SOAP specification was maintained by the XML Protocol Working Group of the World Wide Web Consortium until the group was closed 10 July 2009. SOAP originally stood for "Simple Object Access Protocol" but version 1.2 of the standard dropped this acronym. After SOAP was first introduced, it became the underlying layer of a more complex set of web services, based on WSDL, XSD and UDDI. These different services, especially UDDI, have proved to be of far less interest, but an appreciation of them gives a complete understanding of the expected role of SOAP compared to how web services have actually evolved. SOAP terminology SOAP specification can be broadly defined to be consisting of the following three conceptual components: protocol concepts, encapsulation concepts and network concepts. Protocol concepts SOAP This is a set of rules formalizing and governing the format and processing rules for information exchanged between a SOAP sender and a SOAP receiver. SOAP nodes These are physical/logical machines with processing units which are used to transmit/forward, receive and process SOAP messages. These are analogous to nodes in a network. SOAP roles Over the path of a SOAP message, all nodes assume a specific role. The role of the node defines the action that the node performs on the message it receives. For example, a role "none" means that no node will process the SOAP header in any way and simply transmit the message along its path. SOAP protocol binding A SOAP message needs to work in conjunction with other protocols to be transferred over a network. For example, a SOAP message could use TCP as a lower layer protocol to transfer messages. These bindings are defined in the SOAP protocol binding framework. SOAP features SOAP provides a messaging framework only. However, it can be extended to add features such as reliability, security etc. There are rules to be followed when adding features to the SOAP framework. SOAP module A collection of specifications regarding the semantics