At its core is the SAML Metadata Interop sepcification, having the advantage to scale beyond enterprise-to-cloud use cases, allowing for meshes of many IDPs and SPs. It has its heritage in the research and higher education federations. Related to it is the saml2int deployment profile (http://saml2int.org) that is related to the former profile.
I would recommend to use the Kantara Federation-Interoperability Profile as a better profile: https://kantarainitiative.github.io/SAMLprofiles/fedinterop.html
At its core is the SAML Metadata Interop sepcification, having the advantage to scale beyond enterprise-to-cloud use cases, allowing for meshes of many IDPs and SPs. It has its heritage in the research and higher education federations. Related to it is the saml2int deployment profile (http://saml2int.org) that is related to the former profile.