改进的CFDP协议延时估算算法

Improved Algorithm of CFDP Delay Estimation

为在深空环境下可靠地传输文件,研究CCSDS的异步否定确认信息型文件传输协议CFDP的文件传输机理,根据动态调整定时器的方法,提出一种改进的CFDP协议延时估算算法。在带宽有限的情况下,接收端通过预测单程时延判断网络状况,根据网络状况优化设置NAK触发时刻和定时器时限值。在NS2下的分析结果表明,改进算法的文件传输时间较少,吞吐量较大。

To support reliable file transfer in deep space communication environment,this paper studies the transporting mechanism of asynchronous NAK mode of CCSDS File Delivery Protocol（CFDP）.According to the dynamic adjustment timer method,this paper proposes an improved algorithm of CFDP latency estimation.In asynchronous NAK mode under bandwidth constrain,the algorithm through the predicted one-way delay to judge the network condition,NAK trigger and timer rule is optimized.Analysis results in NS2 show that the file delivery time of this algorithm is less and the throughput is larger.