COTS Switch工业以太网实时调度算法

针对基于商用现成组件技术（Commercial Off-The-Shelf，COTS）的交换式以太网不能满足工业数据通信的实时性要求问题，给出了改进的FTT（Flexible Time-Triggered communication paradigm）网络调度模型，提出了新的周期性实时消息链路可调度性优化判定方法，在此基础上设计了一种基于EDF（Earliest Deadline First）的实时调度算法。算法通过对网络消息流量进行有效控制防止交换机缓冲区溢出，同时充分发挥网络在同一时间存在多个并行传输链路的优势，提高了网络实时性。仿真实验表明该算法在提高网络的聚合带宽、减小消息的平均等待延时和丢失率方面均有明显的优势。

Research on scheduling algorithm for industrial communication over COTS-based switched Ethernet

To overcome the drawback that COTS-based switched Ethernet can not meet the real-time requirements in industrial communications,an improved FTT（Flexible Time-Triggered communication） paradigm which is based on event- and time-triggered approach is proposed.In addition,a novel link scheduling method for periodic messages is given.Particularly,it proposes an EDF-based scheduling algorithm which can provide adequate queues management and prevent memory overflows on a switched Ethernet by limiting the load submitted to the network.Moreover,it becomes possible for the scheduler to take full advantage of multiple transmission paths,thus enhancing real-time communication over a COTS-based switched Ethernet.Simulation results show the advantages of the proposed real-time scheduling algorithm in terms of increasing the aggregated bandwidth,reducing the average message waiting delay and the missing rate of message.