AD FS components
When the AD FS role is installed, there are few related components we need to be aware of. Before Windows Server 2012 R2, there were four AD FS roles services: the federation service, the federation service proxy, the claim-aware agent, and windows token-based agent (to support the AD FS 1.x interoperability). These are no longer available as role services; and when go to install AD FS, it will only have the Federation Service role.
Federation Service
This is the main role service for the AD FS, and it can work on IdP as well as the SP end. In order to install the AD FS role service, system needs to be a member server of an AD domain. Depending on the workload, multiple federation servers can be installed under the same domain, and it is called as AD FS Farm. The federation server is responsible for generating security tokens and signing them with its signing certificate. There have been very few versions of AD FS so far.
AD FS 1.0
AD FS first introduced with Windows Server...