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In computer security, AAA commonly stands for “authentication, authorization and accounting”. This is a misnomer, and should have been “authentication, access control and accounting”. See below and the Wikipedia article on authorization for an explanation. The AAA is sometimes combined with auditing and accordingly becomes AAAA.

Contents 1 Authentication 2 Authorization 3 Accounting 4 Requirements 5 List of AAA Protocols 6 Usage of AAA servers in CDMA data networks 7 External links

[edit] Authentication

Authentication refers to the process where one entity verifies another entity's claim to holding a specific digital identity. Commonly one entity is a client (a user, a client computer, etc.) and the other entity is a server (computer). Authentication is accomplished via the claimant's presentation of an identifier and its corresponding credentials to the verifier. Examples of types of credentials are passwords, one-time tokens, digital certificates, and phone numbers (calling/called).

[edit] Authorization

This is a misnomer, and should have been Access Control. "To authorize" means "to specify access policy" which is also an important security function, but which is not explicitly part of AAA. The function that the middle "A" in AAA actually refers to is "access control", i.e. the granting or refusing of privileges to an entity for accessing specific services.^{[citation needed]} When reading AAA literature, "authorization" must be interpreted as "access control". The access control function uses the access policy specified for an entity to determine whether an access requests from the entity shall be granted or rejected. Access control may be based on restrictions, for example time-of-day restrictions, or physical location restrictions, or restrictions against multiple logins by the same entity or user. Access privileges normally enables an entity to use a specific service. Examples of types of service include, but are not limited to: IP address filtering, address assignment, route assignment, Quality of Service/differential services, bandwidth control/traffic management, compulsory tunneling to a specific endpoint, and encryption.

[edit] Accounting

Accounting refers to the tracking of the consumption of network resources by users. This information may be used for management, planning, billing, or other purposes. Real-time accounting refers to accounting information that is delivered concurrently with the consumption of the resources. Batch accounting refers to accounting information that is saved until it is delivered at a later time. Typical information that is gathered in accounting is the identity of the user, the nature of the service delivered, when the service began, and when it ended.

[edit] Requirements

• RFC 2194 Review of Roaming Implementations
• RFC 2477 Criteria for Evaluating Roaming Protocols
• RFC 2881 Network Access Server Requirements Next Generation (NASREQNG) NAS Model
• RFC 2903 Generic AAA Architecture
• RFC 2904 AAA Authorization Framework
• RFC 2905 AAA Authorization Application Examples
• RFC 2906 AAA Authorization Requirements
• RFC 3169 Criteria for Evaluating Network Access Server Protocols
• RFC 3539 AAA Transport Profile
• RFC 1234 AAA Transport Profile

[edit] List of AAA Protocols

• RADIUS
• Diameter
• TACACS
• TACACS+

Other protocols used in combination with the above:

• PPP
• EAP
• HIP
• PEAP
• LEAP
• LDAP

[edit] Usage of AAA servers in CDMA data networks

AAA servers in CDMA data networks are entities that provide Internet Protocol (IP) functionality to support the functions of authentication, authorization and accounting. The AAA server in the CDMA wireless data network architecture is similar to the HLR in the CDMA wireless voice network architecture.

Types of AAA servers include the following:

• Access Network AAA (AN-AAA) – Communicates with the RNC in the Access Network (AN) to enable authentication and authorization functions to be performed at the AN. The interface between AN and AN-AAA is known as the A12 interface.
• Broker AAA (B-AAA) – Acts as an intermediary to proxy AAA traffic between roaming partner networks (i.e., between the H-AAA server in the home network and V-AAA server in the serving network). B-AAA servers are used in CRX networks to enable CRX providers to offer billing settlement functions.
• Home AAA (H-AAA) – The AAA server in the roamer's home network. The H-AAA is similar to the HLR in voice. The H-AAA stores user profile information, responds to authentication requests, and collects accounting information.
• Visited AAA (V-AAA) – The AAA server in the visited network from which a roamer is receiving service. The V-AAA in the serving network communicates with the H-AAA in a roamer's home network. Authentication requests and accounting information are forwarded by the V-AAA to the H-AAA, either directly or through a B-AAA.

Current AAA servers communicate using the RADIUS protocol. As such, TIA specifications refer to AAA servers as RADIUS servers. However, future AAA servers are expected to use a successor protocol to RADIUS known as Diameter.

The behavior of AAA servers (RADIUS servers) in the CDMA2000 wireless IP network is specified in TIA-835.

[edit] External links

• The webpage of the Authentication, Authorization and Accounting IETF working group