**3.3 Hierarchical scheduling**

In two-level hierarchical scheduling one can identify a global scheduler which is responsible for selecting a component. The component is then free to use any local scheduler to select a task to run.

In order to facilitate the reuse of existing components when integrating them to form larger systems, the platform should support (at least) fixed-priority preemptive scheduling at the local level within components (since it is a de-facto standard in the industry). To give the system designer the most freedom it should support arbitrary schedulers at the global level. In this paper we will focus on a fixed-priority scheduler on both local and global level.
