Which of the following AAA protocols is most commonly used in networking environments?

In networking environments, the most commonly used AAA (Authentication, Authorization, and Accounting) protocol is RADIUS (Remote Authentication Dial-In User Service). RADIUS is widely utilized for facilitating access control and managing authentication across various types of network devices and services, particularly for remote access VPNs and wireless networks.

RADIUS operates as a client-server model, where the network access server (NAS) acts as the client and communicates with the RADIUS server, which handles the authentication requests. It is streamlined for performance in large-scale implementations and supports features like centralized management of user identity and credentials. RADIUS utilizes UDP for transport, which allows it to be lightweight and efficient for real-time operating environments.

While TACACS+ (Terminal Access Controller Access-Control System Plus) is also an AAA protocol, it is less frequently deployed compared to RADIUS. TACACS+ offers enhanced security features by encrypting the entire packet, making it more secure for certain applications, but RADIUS is generally preferred due to its ease of integration and established presence in many network setups.

LDAP (Lightweight Directory Access Protocol) primarily serves as a directory service protocol rather than a dedicated AAA solution, although it is commonly used for accessing user information stored in directories. Kerberos is a network authentication protocol