AAA

AAA refers to the combination of authentication, authorization, and accounting used to manage and control user access to network resources. By using AAA, you can define which network resources users can access, and allow authorized users to access specified resources and services. It is widely used in corporate internal networks, Internet service providers, and wireless networks to ensure that only authorized users can access specific network resources and monitor their network activities.

Three Major Elements of AAA

Authentication

Authentication is the process of verifying the identity of a user and whether he or she is authorized. It verifies the user's username, password, and digital certificate to confirm whether they have legal access rights. The AAA server verifies whether the user's identity credentials are authentic and valid by checking the information stored in the database. Once the verification is passed, the user can access the authorized network resources.

Authorization

Authorization refers to the user's access to specific network resources through the authorization information obtained after identity authentication. It determines which operations the user can perform or which resources it can access. Authorization allows specific operations based on predefined policies or rules. Users can obtain three authorizations for commands, resources, and information after completing identity authentication. Authorization follows the principle of least privilege, that is, without additional authorization, users only obtain permission to perform the required functions, which can minimize the risk of attacks.

Accounting

Accounting is the process of recording user activities in the network, usually including access duration, resource usage, and operation records. This data can be used for time-based or traffic-based billing, behavior auditing, and security analysis.

How AAA Works

The basic workflow of AAA is not as complicated as imagined. The main process is authentication, authorization, and billing. First, the user connects to the AAA client for identity authentication. The AAA client will forward the identity credentials provided by the user to the AAA server and verify whether the user's identity credentials are valid by comparing the stored information. After verifying the user's identity credentials, the AAA server approves the user's access to the network and forwards the identity authentication and pre-set authorization results to the AAA client. The AAA client will determine the resources and services that the user can access based on the authentication and authorization results.

Within the AAA framework, the AAA client runs on a network access server, such as a switch or router, to provide network access services. The AAA server is responsible for the authentication, authorization, and billing of user identity credentials and the centralized storage and management of user identity information. Finally, depending on the communication protocol, the AAA server will be divided into a RADIUS server or a TACACS server.

Common AAA Protocols

AAA usually uses multiple protocols to perform authentication, authorization, and accounting functions in different scenarios, as follows:

RADIUS

RADIUS has become a protocol supported by most equipment vendors due to its simplicity, reliability, and wide support for multiple types of network access, making it a standard choice for managing remote access and wireless networks. It is widely used in access servers, VPNs, wireless networks, and dial-up services.

TACACS+

TACACS+ provides independent control of AAA functions compared to RADIUS, making it more flexible in complex network environments. It not only supports username and password-based authentication but also supports more complex multi-factor authentication. It allows the definition of fine-grained permissions to control the specific commands and access rights that users can execute, which makes it suitable for enterprises to perform precise permission management on network devices and reduce the risk of data leakage.

Diameter

Diameter solves the limitations of RADIUS in terms of scalability, security, and complexity. It can handle larger data loads and supports advanced encryption and transmission security mechanisms. Its design is more modular and can adapt to the complex needs of modern telecommunications and large enterprise networks.

Conclusion

AAA ensures that only authenticated users can access network resources and monitor their activities through the three functions of authentication, authorization, and accounting. RADIUS, TACACS+, and Diameter are commonly used AAA protocols, which are respectively applicable to different scenarios such as remote access, enterprise network management, and telecommunications networks. The flexibility and scalability of the AAA framework make it widely used in various network environments and become a key technology for network security management. It effectively protects the security of network resources and improves network management efficiency. If you have any other questions about AAA, please feel free to contact QSFPTEK's CCIE/HCIE engineers at [email protected].