Packet Scheduling of Two Classes Flow

Various techniques have been proposed to achieve good QoS for diverse application types at network nodes. In order to supply the various QoS requirements for different kinds of applications, new scheduling policies need to be developed and evaluated. Many scheduling techniques have been proposed to respond to the temporal requirements of real-time flows. We propose a new scheduling Hierarchical Hybrid EDF/FIFO for network service, which considers the real time flow have higher priority to service. The technique uses the algorithm Earliest Deadline First (EDF) 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. Our approach for scheduling is nonpreemptive and based in two queues. The first queue for real time flow (class-1) combines the two policies EDF and First in First out (FIFO) to reduce the complexity of EDF. The second queue for non real time flow (class-2) is scheduled by FIFO policy. The work complexity of our approach is less or equal than O(n log2 n) with n is the length of the hierarchical queue. The simulation results underline the effectiveness of this approach.