为了改善工业以太环网的服务质量,减少帧的冲突、阻塞和丢失,提出了工业以太环网的最低松弛度优先（IERN-LLF）信息调度算法,并证明了在网络所有帧同一时间释放的条件下,IERN-LLF算法是工业以太环网最优的信息调度算法.仿真结果显示,与最早时间限优先（EDF）和单调速率（RM）调度算法相比,工业以太环网在IERN-LLF算法调度下帧的丢失率最低,表明IERN-LLF算法可以有效地减少帧的冲突、阻塞,降低网络丢包率,提高网络控制系统的稳定性.

In order to improve the quality of service of the industrial Ethernet ring network and avoid the frame conflict,congestion and loss,a least laxity first information scheduling algorithm of industrial Ethernet ring network,namely IERN-LLF,is presented.IERN-LLF is proved to be an optimal scheduling algorithm for the industrial Ethernet ring network when all frames are released at the same time.Simulated results indicate that,as compared with the EDF and RM algorithms,IERN-LLF algorithm is of the lowest frame loss rate in the industrial Ethernet ring network,which means that IERN-LLF algorithm is effective in reducing frame conflict,congestion and loss and improving the stability of networked control systems.