Large scale federations have more than 100+ identity and or service providers and it is a tedious task to establish bi-lateral relationships with Access Manager. You as an identity provider can now configure several identity providers and service providers by using a multi-entity metadata file available in a central repository.
The identity and service providers can maintain a single metadata file containing metadata of all the approved partners. Identity providers and service providers submit their metadata that includes specifications of services offered (SAML 1.1 and SAML 2.0) and any other information. This feature is available only for SAML 1.1 and SAML 2.0.
For example, XYZ is an e-book store and several e-book stores, which are identity providers or service providers, are partners of XYZ. Hence, XYZ maintains a single metadata file that contains metadata of all other stores. ABC an e-book identity provider wants to establish a federation with many other e-book stores. Hence, ABC partners with XYZ by sharing its metadata and XYZ in turn shares the metadata XML file. ABC imports the XML file available publicly on the internet (for example, http://xyz.commonfederation.org/xyz-metadata.xml) and establishes trusts with others in the federation, which includes XYZ’s trusted provider sites.