What is the "Institutional Login" (Shibboleth authentication)?

The Institutional Login is the system that allows authorization between an university and providers so the members of the university can use several provider services with single sign-on. The ID should be supplied by the university.
In Japan, "GakuNin" is the federation for universities (academic institutions) and providers.
It constructs a framework of the Shibboleth authentication.
GakuNin accept an entry from universities, please see [GakuNin] page for more details. From abroad, users of UK Federation also can use Institutional Login.