航空电子全双工交换式以太网(AFDX)采用信用量令牌桶进行流量管制,为确保信用量设置的合理性,需要考虑虚拟链路(VL)的时延抖动情况。利用网络演算计算VL流量延迟边界,利用"Group"方法获得VL在整个网络中的分布式时延抖动大小,以此为基础分析时延抖动值对信用量设置的影响,利用等效带宽比概念提出交换节点流量带宽约束条件,构建4种不同通信完整性级别的约束准则,为交换节点信用量的合理设置提供设置参考。
Avionics full duplex switched Ethernet(AFDX)adopts credited token bucket consume model for real-time communication traffic policing.To ensure the rationality of the setting of credit amounts,the jitters of virtual links(VL)need to be considered.Network calculus model was used to calculate VL flow end-to-end delays,and the"Group"method was used to obtain the distributed delays of VL in the whole network.Based on the distributed delays,the influence of jitter value on credit amount setting was analyzed.By using the equivalent bandwidth concept,the flow bandwidth constraints for switching nodes were proposed,and four constraint conditions models for different communication integrity levels were established,which provided a reasonable reference for the setting of credit values.