主从结构交换式以太网中实时消息调度研究

为使交换式以太网能满足实时通信的要求，针对FTT SE网络调度模型，提出了一种同时适用于周期性和非周期性实时消息的链路可调度性判定方法。在证明了消息链路调度优化问题MLSOP为NP complete的同时，针对周期性实时消息的链路调度优化给出了启发式算法LSHA。最后,对于周期性和非周期性实时消息分别设计了基于EDF的调度算法。仿真实验表明,在提高网络链路带宽利用率和减小消息平均延时方面,该算法均较FTT SE有明显的优势。

Research on scheduling of real-time messages over master-slave switched Ethernet

To make switched Ethernet meet the requirements of real-time communication, a novel link schedulability analysis method for both periodic and aperiodic real time messages is proposed based on FTT-SE (Flexible Time Triggered Switched Ethernet) paradigm. In addition, it is proved that finding the optimal schedule for a given set of periodic messages on transmission links in order to minimize the maximum finishing time of reception links is NP-complete, and a heuristics algorithm named LSHA is proposed to solve this problem. Particularly, we design different EDF-based scheduling algorithms for periodic and aperiodic real-time messages respectively, which make it possible for the scheduler to take full advantage of multiple transmission paths, thus enhance the real time communication over a COTS based switched Ethernet. Simulation results show that the proposed Real-Time scheduling algorithm outperforms FTT SE in terms of enhancing network bandwidth utilization and reducing average message delay.