中文摘要：

针对现有联合输入交叉点排队交换结构（CICQ,Combined Input and Cross-point Queuing）调度策略无法提供基于＂流＂的服务质量保障,探讨了在CICQ交换结构实施基于流调度的可能性,提出一种能够为到达流提供公平服务的分层混合公平服务调度策略—LHFS（Layered and Hybrid Fair Scheduling）.LHFS对每个输入、输出端口可独立地进行变长分组交换,其算法复杂度为O（1）,具有良好可扩展特性.理论分析结果表明,LHFS能够为业务流提供时延上限和公平性保障.最后,基于SPES（Switching Performance Evaluation System）仿真系统对LHFS的性能进行了评估.

英文摘要：

Providing fairness performance for traffic flows is an important requirement for today＇s routing and switching equipments.To meet this requirement,we first discuss the feasibility of implementing flow scheduling in this paper.Then,based on the discussion,it comes up with a layered and hybrid fair scheduling（LHFS） scheme.LHFS is a hierarchical and hybrid algorithm for CICQ（Combined Input and Cross-point Buffered） switches.With LHFS,each input and output port can schedule variable length packets independently with a complexity of O（1）.Theoreuical analyses show that LHFS can provide delay up-bound and fair service guarantees.Finally,we implement LHFS in SPES（Switch Performance Evaluation System） to verify the analytical results.