Efficient Hierarchical Diff-EDF schedulability for QoS packet networks

Packet networks are currently enabling the integration of traffic with a wide range of characteristics that extend from video traffic with stringent QoS requirements to the best-effort traffic requiring no guarantees. QoS guarantees can be provided in packet networks by the use of proper packet scheduling algorithms. In this paper, we propose a new priority assignment scheduling algorithm, hierarchal diff-EDF (differentiate earliest deadline first), which can meet the real-time needs of such applications while continuing to provide best effort service to non-real time traffic. The hierarchal diff-EDF features a feedback control mechanism that detects overload conditions and modifies packet priority assignments accordingly. The simulation results show that the hierarchical diff-EDF achieved the minimum packet miss ratio when compared with both EDF and diff-EDF schedulers.