CONNECT ID is the component of CONNECT dealing with identity management. The main part of CONNECT ID is an authorization server which will handle user signup and login (authentication) for you. In addition to being authenticated, the end user gets the chance to authorize that you get access to his protected resources, like e.g. email address, phone number, and payment functionality. CONNECT ID also supplies APIs to get and manage user data.
Note, the new documentation is work in progress and not all content has been moved over yet. The old docs can still be found at docs.telenordigital.com.