WS-Standards

This article by Eran Chinthaka describes the requirement of understanding the mustUnderstand SOAP header property in designing and implementing Web services.

Both SOAP 1.1 and SOAP 1.2 specifications enable you to use mustUnderstand attributes with SOAP headers. Not handling these headers properly is a common concern during Web service interactions. Within Axis2, repercussions of not understanding some of these mustUnderstand headers is common, especially in those ciscumstances when you try to use add-on modules with Axis2. This article describes the mustUnderstand header field and goes on to explain the cause of such errors. The article also looks at what happens inside Axis2, as such errors are encountered and how some of it can be fixed with minimal effort.

The WS-MetaDataExchange specification defines protocols that support the dynamic exchange of metadata that is relevant to the service interaction (such as XML Schema WS-policy and WSDL descriptions) between Web services endpoints. WS-MetadataExchange specification  provides more information you need to know about it.