Typically, this is done through some form of Identity Broker application.
Many people confuse Consistent Sign-On (CSO) with Single Sign-On and often what Organizations end up with is Reduced Sign-On (RSO).
There are several specific implementations of Single Sign-On:
Many Organizations heterogeneous approach to Single Sign-On implementing one or more through an Identity Broker type product.
Often, Single Sign-On applications will implement a form of Identity Brokering to allow Cross-domain authentication and/or Cross-platform Authentication
Single Sign-On usually also involves a Identity Federation.Single Sign-On may be provided as part of a Cloud Access Security Broker
OpenID Connect Federation often does not require User Provisioning (however the application may still require provisioning.)!! Single Sign-On and Authorization Many Single Sign-On implementations do not provide Authorization to the level that may be required.
Perhaps we need a Graded Authentication