Cooperative Secondary Authorization Recycling

As distributed applications such as Grid and enterprise systems scale up and become increasingly complex, their authorization infrastructures—based predominantly on the request-response paradigm—are facing challenges in terms of fragility and poor scalability. We propose an approach where each application server caches previously received authorizations at its secondary decision point and shares them with other application servers to mask authorization server failures and network delays. This paper presents the design of our cooperative secondary authorization recycling system and its evaluation using simulation and prototype implementation. The results demonstrate that our approach improves the availability of authorization infrastructures while preserving their performance characteristics. Specifically, by sharing authorizations, the cache hit rate—an indirect metric of availability—can reach 70%, even when only 10% of authorizations are cached. Depending on the deployment scenario, the performance in terms of the average time for authorizing an application request can be reduced by up to 30%.