SCI/RT协议仲裁传输的一种仲裁方法

An Arbitration Method on SCI/RT Arbitration Transmission

通过分析SCI/RTTRAIN协议的仲裁传输算法,发现环路处于重负载情况时,环路的列车传输空间有浪费的情况存在,且数据传输会出现优先级倒置的情况。在环路存在热点(hotspot)节点时,列车空间浪费情况依赖于阻塞节点在环路的位置。本文提出基于广播节点输入队列信息的仲裁传输新方法,通过按需广播热点节点的输入队列状态,减少数据传输请求被拒绝概率,从而提高环路传输的效率。通过使用OPNET软件仿真对比,得到该方法在环路处于小负载时不带来明显开销;在重负载时,减小传输延迟,提高环路流量的结果。

The scalable coherent interface for real time（SCI/RT） TRAIN protocol is analyzed. The results show the ringlet capacity is wasted with heavy ringlet throughput, and in case of the heavy ringlet load, the priority inversion is appeared. When the ringlet has hotspot nodes, the state of capacity wasted is greatly dependent on the position of blocked node. A new method based on broadcasting status of input queue is proposed. By reducing the rate of ticket rejecting, the new method transfers packages more effectively than the standard one. The SCI/RT ringlet with 6 nodes is simulated by the OPNETTM software. The results show that the new method gets more throughput and lower transferring delay than the standard one, and it reduces the priority inversion problem.