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为满足未来航电系统音视频信息传输的需求,考虑车载嵌入式系统的候选实时多媒体网络AVB(Audio Video Bridging)在航电环境中的应用,并实施AVB与AFDX(Avionics Full-Duple X switched Ethernet)的传输对比研究。首先构建AVB与AFDX标准对比;其次提出基于网络演算的AVB和AFDX端到端延迟计算方法;然后通过定义不同的消息传输场景,采用理论方法分析消息传输实时性的干扰要素;并利用仿真方法予以验证。在典型1000条虚拟链路的组网规模下,结果显示:AFDX高优先级流量的端到端延迟优于AVB,对于低优先级流量端到端延迟,则AVB和AFDX各有优劣;但受突发的流量影响,在增加50条各0.22M带宽的低优先级流量干扰情况下,高优先级流平均端到端延迟的变化率在AVB中为0.25%,在AFDX中为0.38%。在增加50条各0.22M带宽的高优先级流量干扰情况下,低优先级流平均端到端延迟的变化率在AVB中为5.17%,在AFDX中为10.25%。结果表明:时间敏感消息在AVB网络中传输实时性的抗干扰能力优于AFDX。
In order to meet the demand of audio and video information transmission of avionics system in the future, the application of AVB (Audio Video Bridging), a candidate real-time multimedia network in vehicle embedded system, to avionics environment is considered and AVB and AFDX (Avionics Full-Duple X switched Ethernet ) Transmission comparison study. Firstly, the AVB and AFDX standards are compared. Secondly, the calculation method of end-to-end delay of AVB and AFDX based on network calculus is proposed. Then, different message transmission scenarios are defined, and the real-time interference elements of message transmission are analyzed theoretically. verification. The result shows that the end-to-end delay of high-priority AFDX traffic is better than that of AVB at a typical 1000 virtual link network size. However, for end-to-end delay of low priority traffic, both AVB and AFDX have advantages and disadvantages; Under the condition of sudden traffic, the average end-to-end delay of high priority flows is 0.25% in AVB and 0.38% in AFDX with 50 low-priority traffic interferences of 0.22M each. With 50 high-priority traffic interferences of 0.22 Mbit / s each, the average end-to-end delay of low-priority flows is 5.17% in AVB and 10.25% in AFDX. The result shows that the real-time anti-interference ability of time-sensitive message is better than AFDX in AVB network.