基于抖动测试的AFDX端到端延迟紧性修正

A Tightening Method of AFDX End-to-End Delay Based on Jitter Tests

摘要:

AFDX引入虚拟链路(Virtual Link)实现物理带宽资源的逻辑分隔。由于数据帧的异步到达和多路复用输出造成虚拟链路的时延抖动现象,并最终导致流量端到端延迟分析的不确定性。本文提出了一种基于抖动测试值的网络演算紧缩方法。通过分布式测试,获得虚拟链路在网络中的实际传输抖动,并以此为基础,建立了流量传输精确化模型,通过流量模型的逐级修正,使端到端延迟计算结果逐级精确化。通过将抖动实际值与理论分析结果相结合,提供了网络演算悲观度及其扩散影响度量的直观对比,提高了延迟计算的紧性。

Abstract:

AFDX uses Virtual Link to realize the logical separation of the physical bandwidth resources. The delay jitter on virtual links is caused by asynchronous arrival and multiplexing output of data frames, which also leads to the uncertainty in the end to end delay analysis. In this paper, a method of network calculation based on jitter test was proposed. The network transmission jitters on VLs have been caught by distributed test. On the foundation of the testing results, a precise flow model was established, and with the stepwise correction of the flow model, the end to end delay was corrected gradually. By combining the actual value of jitter with the theoretical analysis results, a visual result of the network calculus pessimism and its diffusion effect was proposed. This result improves the compactness of the network delay calculation.