<Li> What would be the structure of the data produced . (Normally, data is exchanged in XML files, and the structure of the XML file is validated against an . xsd file .) </Li> <Li> What error messages to display when a certain rule for communication is not observed, to make troubleshooting easier . </Li> <P> All of these rules for communication are defined in a file called WSDL (Web Services Description Language), which has a . wsdl extension . (Proposals for Autonomous Web Services (AWS) seek to develop more flexible web services which do not rely on strict rules .) </P> <P> A directory called UDDI (Universal Description, Discovery and Integration) defines which software system should be contacted for which type of data . So when one software system needs one particular report / data, it would go to the UDDI and find out which other system it can contact for receiving that data . Once the software system finds out which other system it should contact, it would then contact that system using a special protocol called SOAP (Simple Object Access Protocol). The service provider system would first validate the data request by referring to the WSDL file, and then process the request and send the data under the SOAP protocol . </P>

Data exchange between ui and server in modern web architecture using