Hierarchical scheduling for heterogeneous flows

In this present work, we propose a scheduling approach for heterogeneous traffic over network. The proposed scheduling not only satisfies the QoS requirements of the real time flows (class-1) but also continues providing best effort service to non real time flows (class-2). Many scheduling techniques have been proposed to respond to the temporal requirements of real-time jobs (flows). The technique using the algorithm Earliest Deadline First (EDF) is most used because the optimality of this algorithm has been proved for a number of criteria. However, this algorithm knows a complexity that increases with the size of queue. In order to not penalize the flows of class-2, we propose an approach for scheduling non-preemptive basis in two queues. The first is a hybrid queue for class-1 that combines the two policies First in First out (FIFO) and EDF to reduce the complexity of EDF. The second queue for class-2 is scheduled by FIFO policy. The performances of the proposed approach are evaluated by the miss deadline of the packet in the hybrid queue the class-1 and the average time of residence of packet in the FIFO queue of class-2. The simulation results underline that the existing errors are relatively weak which confirm the effectiveness of this approach.