eduGAIN
The eduGAIN interfederation service connects identity federations around the world, simplifying access to content, services and resources for the global research and education community. It is a platform for participating identity federations, and their users and services, to interconnect and collaborate.
There are more than 55 federations around the world,consisting of more than 2,600 identity providers and 1,800 service providers, which are participating in or in the process of joining eduGAIN.
Information on eduGAIN: https://edugain.org/