Deterministic end-to-end delay guarantees with rate controlled EDF scheduling

Quality of Service (QoS) in terms of end-to-end delay guarantees to real-time applications is an important issue in emerging broadband packet networks. Earliest Deadline First (EDF) scheduling, in conjunction with per-hop traffic shaping (jointly called Rate Controlled EDF or RC-EDF) has been recognised as an effective means of end-to-end deterministic delay provisioning. This paper addresses the issue of identifying RC-EDF shaping parameters that realize maximal network utilizations. We first prove that finding "optimal" shapers is in general infeasible, and then propose a heuristic choice derived from the flow's hop-length. Our choice varies gracefully between known optimal settings for the limiting values of the hop-length, and outperforms shaper selections proposed previously in the literature.