Why should i have Centralized Authentication? or Why should I integrate Active Directory with AAA router? Of course, Managment is very easy. It is not an integration of AD and AAA, What do we do here is using the Active directory user database for routers' and switches' access. Also every time you need not to login into all the routers and switches just to change password. In order to have a centralized authentication for all the network devices we configured Internet Authentication Service in our Domain Controller to act as a Radius server. Using IAS service we can build a centralized authentication server for all the network devices in both Backbone and Master setup. AAA client also should be configured in all the network devices in order to communicate with IAS Server. What If my Radius Server Fails ? In this blog, I will be covering the backup authentication method also. In case if your Radius servers fails, still your routers and switches can use their local database to a