Optimal Accounting Policies for AAA Systems in Mobile Telecommunications Networks

Authentication, Authorization, and Accounting (AAA) deployments are expected to grow significantly in emerging mobile systems as they offer a plethora of services and mobile applications. In current systems, network access servers (NAS) periodically report the service usage of mobile users located within their coverage areas. The periodic reports are used by the billing systems to minimize the incurred capital losses if the serving NAS fails. While shorter reporting intervals are desired for lower losses, they can potentially result in undesirably high signaling load. Because it is prohibitively difficult to obtain optimal reporting intervals in mobile systems due to multitudes of services with different mobility profiles, current accounting standards offer no quantitative measures for selecting a proper reporting interval and AAA systems are typically designed via over provisioning. To address this issue, we propose an adaptive optimization mechanism in multiservice AAA systems which limits the potential loss without excessively generating unnecessary usage reports. Our optimization mechanism embraces the current AAA IETF standards RADIUS and its successor Diameter and does not require any modifications to the AAA protocols nor to the network access servers' implementation, and its implementation scope is limited to the AAA systems. The results demonstrate that our mechanism is robust under various operational conditions, easy to implement, and offers considerable potential for loss control compared to the current static approaches.