The design of a generic and flexible Authentication, Authorization, Accounting, and Charging Architecture (AAAC Arch) as well as the basic considerations of the AAAC System, which implements the architecture for the mobile Internet has been performed. This paper is based on the work carried out within the Moby Dick project, whose main objective is the facilitation of the deployment of an ubiquitous Mobile IPv6 QoS-aware infrastructure through a best-suited and pragmatic use of an evolutionary AAAC Architecture. While a number of orthogonal use cases of AAAC motivate the necessity of various distinct scenarios, covering Quality-of-Service (QoS) and mobility aspects, these use cases form the basis for the understanding and investigations on AAAC tasks, functions, components, and interactions to enable a problem description and requirements specification on a very fine-grained level. The AAAC Architecture design considerations take up those problems and define a clear solution space, covering in detail logical and physical components and their interactions, identifiers, a session model, profiles, and a security model. This paper closes with the projection of an implementation architecture for the proposed AAAC Arch, which will enable the instantiation of these concepts and their protocols in a given Internet.