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As can be seen from the architecture diagram the Web Service Provider registers the Web Service to UDDI registry and provides WSDL for invoking service. The Web Service consumer which can be an application client or any other Web Service queries the UDDI registry and finds WSDL. Next the consumer uses WSDL to invoke the SOAP service.

Web Services Description Language(WSDL)

WSDL is a XML way of describing a Web Service. It specifies the location of Web Service and methods available with the service. WSDL is basically a document written in XML. A WSDL document has <portType>, <message>, <types > and <binding> as the elements.