I'm trying to learn how can one protect routers (using Cisco Packet Tracer) and I found out I can set local password to authenticate access to the router privileged and configuration mode. However, I see I can also do it using a RADIUS Server.
The thing that I don't understand is how this last method is better in terms of security than local authentication. I know the password and username are sent to the RADIUS Server encrypted using a shared secret between server and router, in this case, but if you authenticate locally no-one can sniff your packets anyway, so I don't see the point. I guess it's something related to remote access to configurate the router (not sure though), but again I don't understand what would you gain in this case if you used RADIUS vs local.