What is the role of the router or switch in the AAA architecture?

In the context of the AAA architecture—Authentication, Authorization, and Accounting—the role of the network device, such as a router or switch, is to act as a Network Access Server (NAS). This means that these devices serve as the point of entry for users seeking to access network resources. When a user attempts to connect to the network, the router or switch will facilitate the process by gathering the necessary authentication information and then forwarding it to a centralized AAA server for processing.

As a NAS, the router or switch interfaces with end devices and handles requests for access. It ensures that the correct authentication mechanisms are in place, such as invoking RADIUS or TACACS+ protocols to communicate with the AAA server. Once a user’s credentials are verified and authorization is confirmed, the NAS also manages how the user can interact with the network resources, effectively controlling access based on predefined policies.

In summary, by functioning as a NAS, routers and switches play a critical role in the AAA framework, coordinating user access and ensuring secure and controlled network interactions.