TR-IIS-05-006    Fulltext

Enhanced Bulk Scheduling for Supporting End-to-End Delay Requirements

Yung-Cheng Tu, Meng Chang Chen, Yeali S. Sun and Wei-Kuan Shih


Abstract

Providing end-to-end delay guarantees for delay sensitive applications is an important packet scheduling issue of routers. In this paper, to support end-to-end delay requirements, we propose a novel network scheduling scheme, called the Bulk Scheduling Scheme (BSS), built on top of existing schedulers of intermediate nodes without modifying transmission protocols on both sender and receiver sides. By inserting TED packets into packet flows at the ingress router periodically, the BSS schedulers of the intermediate nodes can dynamically allocate the necessary bandwidth to each flow to enforce the end-to-end delay, according to the information in TED packets. The introduction of TED packets incurs a lower overhead than the per-packet marking approaches. Three flow bandwidth estimation methods are presented and their performance properties are analyzed. BSS also provides a dropping policy to discard late packets and a feedback mechanism to discover and resolve the bottlenecks. The simulation results show that BSS performs efficiently as expected.

Keywords: packet scheduling; bulk scheduling; end-to-end delay; QoS