When a user is already authenticated and has established, for example, SSO with the instance of OpenSSO Enterprise at the service provider, the user might click on a Global Logout link. The identity provider will then invalidate its local session (if created) and trigger SAML v2 single log out by invoking a provided OpenSSO Enterprise URL. The OpenSSO Enterprise identity provider executes the SAML v2 single log out, terminating the session on both provider instances of OpenSSO Enterprise.
An identity provider side application can initiate single logout by sending sun.cmd=logout attributes via a Virtual Federation interaction to a local instance of OpenSSO Enterprise acting as the identity provider. In turn, this instance will execute SAML v2 single logout based on the current session.
For more information, see the Sun OpenSSO Enterprise 8.0 Administration Guide.