2.2.1.2 WS-Trust
WS-Federation (section 2.2.1.1) operates directly on top of the HTTP protocol [RFC2616] and, specifically for AD FS, only with passive requesters, that is, web browsers. There is a class of applications that is not covered in the WS-Federation scenarios as implemented in AD FS, namely SOAP-based applications. These applications can also benefit from federation and the use of security tokens for purposes that are similar to those for WS-Federation.
The Web Services Trust Language [WSTrust] is available in AD FS to accommodate SOAP-based applications.