Dell PowerConnect W Clearpass 100 Software 3.9 Deployment Guide - Page 26

Figure 4 Sequence diagram for network access using AAA In the standard AAA framework, network access is provided to a user according to the following process:  The user connects to the network by associating with a local access point [1].  A landing page is displayed to the user [2] which allows them to log into the NAS [3], [4] using the login name and password of their guest account.  The NAS authenticates the user with the RADIUS protocol [5].  ClearPass Guest determines whether the user is authorized, and, if so, returns vendor-specific attributes [6] that are used to configure the NAS based on the user's role [7].  If the user's access is granted, the NAS permits the guest access to the network based on the settings provided by the ClearPass Guest server.  The NAS reports details about the user's session to the ClearPass Guest server using RADIUS accounting messages [8]. After the user's session times out [9], the NAS will return the user to an unauthorized state and finalize the details of the user's session with an accounting update [10]. 26 | Management Overview ClearPass Guest 3.9 | Deployment Guide