Scalability Analysis of the OpenAM Access Control System with the Universal Scalability Law

The scalability of a software system is greatly impacted by the scalability of the underlying access control system, which makes analyzing the scalability of that access control system paramount. However, this is not trivial, as contemporary access control systems have a myriad of architectural deployment variations, each of which has a potentially large impact on overall system throughput. There is a need for a systematic approach to map these architectural variations to a reference model which allows to make comparisons and to identify trade-offs. This work provides a piece of the puzzle by demonstrating how this can be achieved by systematically applying the Universal Scalability Law (USL). We illustrate our approach by performing a rigorous scalability analysis of the OpenAM access control system for various deployment alternatives in the domain of authentication. We conclude that the approach is able to provide both qualitative and quantitative results which can be translated into practical operational recommendations for the envisioned types of system deployments.