A Scalability Study of AAA Support in Heterogeneous Networking Environments with Global Roaming Support

In this paper, we present a scalability study of AAA support in mobile heterogeneous access networks with respect to server and network load related to AAA processes using the RADIUS protocol. Technologies such as IEEE 802.11, CDMA 2000 and UMTS which all support the RADIUS protocol for AAA handling are discussed and analyzed. Typical performance data are gathered and complemented with a theoretical study in order to achieve an overview of what parameters will affect the performance and scalability of the network. Also, guidelines are developed for network design in order to achieve the desired performance for a given number of users. Results of this study include the conclusion that the main bottleneck of the AAA procedure is not necessarily the AAA server CPU power. Aside the cases with a high proportion of computationally intensive WiFi sign-ons with strong encryption, performance issues may be caused by AAA server network connection bandwidth, and RAM memory. In cases where a high number of users reside in the same user database, database performance becomes a significant issue. In order to achieve better performance, CPU load balancing over several servers may be performed.