K.2 Priority of service (FRU_PRS)

The requirements of this family allow the TSF to control the use of resources within the TSC by users and subjects such that high priority activities within the TSC will always be accomplished without interference or delay due to low priority activities. In other words, time critical tasks will not be delayed by tasks that are less time critical.

This family could be applicable to several types of resources, for example, processing capacity, and communication channel capacity.

The Priority of Service mechanism might be passive or active. In a passive Priority of Service system, the system will select the task with the highest priority when given a choice between two waiting applications. While using passive Priority of Service mechanisms, when a low priority task is running, it cannot be interrupted by a high priority task.While using an active Priority of Service mechanisms, lower priority tasks might be interrupted by new high priority tasks.

User notes

The audit requirement states that all reasons for rejection should be audited. It is left to the developer to argue that an operation is not rejected but delayed.