Terminal Access Controller Access Control System Plus

AAA protocol developed by Cisco used to authenticate to administrator accounts for network appliance management.

TACACS+ splits the AAA triad into three seperate protocols, which allows each core function to be ran on a separate server (unlike RADIUS).

TACACS+ runs on 149/tcp. It encrpyts the entire packets along with it's contents, not just the authentication packets. Client-server dialogue is also encrypted. TACACS+ also supports more protocol suites than RADIUS, and it requires remote access servers to become TACACS+ clients to the backend server.