What are the advantages, strengths and/or weaknesses of remote access methods and techniques such as RADIUS, RAS, TACACS+ and VPN?

they store authentication details in the remote server and its retrieval is encrypted. But it can also be very slow when the network signal is down.

Explanation:

Private IP network like in a small or enterprise company needs access control methods to prevent unwanted access to files by unauthorized employees. The regular router ssh authentication is good for a small company but it has no backup storage to hold user login details and easily be hacked by attackers. So the AAA policy is adopted to prevent this. it stands for authentication, authorization and accounting, and uses protocols like the RADIUS, TACAS+, VPN, etc, to prevent unwanted access. it is fast and saves all the login details of all the employees in the network, but experiences slow or no authentication when network is down.