The WS-Federation Language 1.1 specification was published for public review and comment in December 2006. On April 13, 2007, the Organization for the Advancement of Structured Information Standards (OASIS) called for participants to join the proposers of a Web Services Federation Technical Committee to drive standardization of the WS-Federation protocol. Today OASIS announced formation of the WSFED TC to undertake ratification of the WS-Federation 1.1 specification as an OASIS standard.

These actions have sparked a spirited debate in the blogosphere, paraphrased as:

How does WS-Federation relate to the WS-Trust specification that was recently ratified as an OASIS standard?

What does WS-Federation provide that is not already addressed by SAML 2.0?

Why is WS-Federation being republished and proposed for standardization now?

These are good questions. They demonstrate that the open standards process is alive and well in the Federated Identity space. The answers to all three questions have this in common.

WS-Federation extends WS-Trust to provide a flexible federated identity architecture with clean separation between trust mechanisms, security token formats, and the protocol for obtaining tokens. This architecture enables a reusable token service model and protocol to address the identity requirements of both web applications and web services in a variety of trust
relationships.

As one of the authors of WS-Federation I will do my best to provide more detailed explanations of our motivation in subsequent posts.