I know the authentication system of access token is based on OAuth 2.0 specification, my question is, in the future is there any plan to make it a single-sign on application? Just wanted to know how to integrate this with my 3-tier infrastructure.
Federated Authorization is supported today. You can use Authorization code or Implicit grant to get the access token and use this token to invoke any EDP service.
See an example implementation in this tutorial.