1-11 AAA ConfigurationWhen configuring AAA, go to these sections for information you are interested in:z Introduction to AAAz Introduction to RADIUSz Introduction to HWTACACSz Protocols and Standardsz AAA Configuration Task Listz Configuring AAAz Configuring RADIUSz Configuring HWTACACSz AAA Configuration Examplesz Troubleshooting AAAIntroduction to AAAAuthentication, Authorization, and Accounting (AAA) provides a uniform framework for configuringthese three security functions to implement network security management.AAA usually uses a client/server model, where the client runs on the network access server (NAS) andthe server maintains user information centrally. In an AAA network, a NAS is a server for users but aclient for the AAA servers, as shown in Figure 1-1.Figure 1-1 AAA networking diagramWhen a user tries to establish a connection to the NAS and to obtain the rights to access other networksor some network resources, the NAS authenticates the user or the corresponding connection. The NAScan transparently pass the user’s AAA information to the server (RADIUS server or HWTACACS server).The RADIUS/HWTACACS protocol defines how a NAS and a server exchange user informationbetween them.In the AAA network shown in Figure 1-1, there is a RADIUS server and an HWTACACS server. You candetermine the authentication, authorization and accounting methods according to the actual
