RBAC relates more to authorization rather than authentication. Authentication verifies the user's account on the system, usually with an identity credential, like a user ID and password. Authorization verifies what data the user is allowed to access after being authenticated.
If a user is authenticated and has access to the system, it doesn't necessarily mean that he or she has access to everything on it.
Groups are assigned based on the security needs of a business or organization. There is no cookie-cutter approach to RBAC. It has to be tailor-made for each system, but that's not necessarily a bad thing. You wouldn't want your marketing staff, for example, to have access to payroll information that should only be visible to, say, human resources. Nor would you want human resources to know about upcoming marketing promotions that should be kept under wraps. With RBAC, everyone, including human resources and marketing, would have their own individual accounts, but their accounts would be part of their respective groups.
When lumping accounts for RBAC, both Active Directory in Windows and LDAP in Unix can be used to create groups.
This was first published in December 2006