Web Single Sign-On Metadata Exchange Protocol

Web Single Sign-On Metadata Exchange Protocol is a Web Services and Federated identity specification, published by Microsoft and Sun Microsystems that defines mechanisms for a service to query an identity provider for metadata concerning

the protocol suites it supports. The goal of this operation is to increase the ability of a given service to interoperate with a given identity provider.[http://xml.coverpages.org/ni2005-05-16-a.html Cover Pages: Microsoft and Sun Publish Web Single Sign-On (SSO) Identity Specifications]