Abstract: One of the main problems of applying the switched Ethernet to control applications is how to adapt it to the typical industrial communication with least changes.Considering the communication characteristics of the control network，this paper proposes a distributed bandwidth allocation strategy based on the time-slot.Models of communication tasks and bandwidth resources in the network control system based on switched Ethernet together with the control methods of the message transmission and the scheduling algorithm of the strategy are introduced.Existing distributed scheduling proposals often cannot deal with the situation that communication tasks change frequently and both schedulable ratio and bandwidth utilization are low.By the experimental analysis and comparisons，the proposed strategy guarantees the transmission of the real-time communication tasks with their deadlines，and furthermore it solves the above problems of existing proposals.

Key words: network control, bandwidth allocation, switched Ethernet

摘要： 交换式以太网应用于控制领域所面临的主要问题之一是如何以尽量小的代价来实现其支持典型的工业通信的目的。结合控制网络的通信特点，提出了一套基于时隙的分布式带宽分配策略。介绍了基于交换式以太网的网络控制系统中通信任务和带宽资源的模型、调度策略中信息传输的控制方法和调度算法。通过实验分析和比较，该策略在满足了各通信任务实时需求的同时，解决了当前的分布式调度策略中存在的诸如不能灵活应对通信任务频繁变化、任务调度率和带宽利用率低等问题。

关键词: 网络控制, 带宽分配, 交换式以太网