An Admission Control Protocol for Real-Time OSGi

In previous work we motivated the need for using the OSGi Framework with the RTSJ to develop real-time systems. We found a number of issues with using these technologies together. One of the issues we discovered was unbounded dynamism caused by the absence of admission control. Components can be uninstalled, installed and updated without regulation. This means that it is impossible to guarantee resources to components. In this paper, we propose a solution to the unbounded dynamism problem by providing an admission control protocol for real-time OSGi. We also provide a priority assignment approach to support temporal isolation. The combination of admission control and temporal isolation ensure that it is safe to update components or install components into the system in terms of guaranteeing resources to components. We show the practicality of our admission control protocol by implementing a prototype and measuring the execution time overhead incurred when performing a component install with admission control.