This part of the book explains the technologies that are available for describing services. The immediate and pervasive nature of this metadata distinguishes the Web services platform from many other distributed computing systems. The figure that follows shows where you are in the Web services stack.
Chapter 6, "Web Services Description Language," discusses the Web Service Description Language (WSDL). WSDL allows you to describe a service in terms of what it does and then specify where the users of the service can locate it and how they should interact with it. This chapter discusses both the currently popular WSDL 1.1 version and the up-and-coming WSDL 2.0 version.
Chapter 7, "Web Services Policy," discusses the WS-Policy family of specifications. WS-Policy is a framework of specifications for defining and associating policies with Web service descriptions. The actual policies are domain specific, but the framework offers standard mechanisms to combine policies and to attach them to WSDL documents and other Web service components.
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