Definition of terms

Authentication, Authorization, and Accounting services. This is typically provided by a single protocol (For example, RADIUS, TACACS+).

Network Access Server is an industry term for devices that provide authorization services by communicating with AAA server. For example, Aruba switches

Ability to specify the outgoing IP on switch generated packets to ease network service deployment (for example, RADIUS/TACACS+ using a single address to connect to NAS).