WS-Policy
From Bandit-project.org
Nutshell
Web services Policy (WS-Policy) defines a grammar or syntax to express additional information required for Web services to communicate. This additional information is a set of requirements that need to be met by a requestor of a Web service. These requirements are not specified by WS-Policy only the XML grammar on how to represent them.
Why?
There is no way for a Web service to explain certain details about its service. Until WS-Policy this information had to be retrieve via documentation, emailing the host, etc. WSDL and UDDI allows for the discover of the service but not details on how to communicate with it.
For example, lets say you want to talk to a certain Web service. This service will only respond to requests over a certain level of SSL encryption. The web service would define a WS-Policy that explains this so that you can make sure you fulfill that requirement before attempting to access it.
Links
WS-Policy Specification
Open source implementation of the specification
Web Service Policy What Why and How, Sanka Samaranayake
