基于软件定义网络的卫星网络容错路由机制

Software defined network based fault tolerant routing mechanism for satellite networks

鉴于卫星网络对安全性和应对故障的能力有很高的要求,引入了软件定义网络(SDN)技术,在网络中放置中央控制器来增强网络对故障的应对能力。首先,基于SDN的思想设计了一种卫星网络模型,计算了三层轨道上卫星运行的参数并构建星座;然后,采用分层路由的方法,设计了一种针对卫星网络的容错路由机制;最后,在Mininet平台上进行了仿真实验,将容错路由算法(FTR)的实验结果与基于链路感知的星间路由算法(LRSR)和多层卫星网络路由算法(MLSR)的实验结果进行了对比。对比结果表明,在网络中无损坏节点和链路的情况下,FTR的路由总延时比LRSR平均降低了6.06%,说明了引入SDN集中控制的有效性;FTR的丢包率比同样以最小延时为目标的MLSR降低了25.79%,说明了在网络模型中为中轨道(MEO)卫星设计临时存储路由机制的有效性。而当网络中节点和链路的失效情况比较严重时,FTR的路由总延时比LRSR降低了3.99%,比MLSR降低了19.19%;其丢包率比LRSR降低了16.94%,比MLSR降低了37.95%,说明了FTR的容错有效性。实验结果验证了基于SDN的卫星网络路由机制具有更好的容错能力。

Duing to the satellite network has high requirement for security and fault-dealing ability, with Software Defined Network(SDN) technology introduced, the central controller was set in the network to enhance the network’s fault-dealing ability. Firstly, a satellite network model was designed based on the SDN idea, and the satellite’s operating parameters on the three-layer orbit were calculated and the constellations were built. Then, the method of hierarchical routing was used to design a fault tolerant routing mechanism for satellite network. Finally, the simulation experiments were carried out on the Mininet platform, and the experimental results of Fault-Tolerant Routing algorithm(FTR) were compared with the results of inter-Satellite Routing algorithm based on Link Recognizing(LRSR) and Multi-Layered Satellite Routing algorithm(MLSR). The comparison results show that in the case without damaged nodes or links in the network, the total routing delay of FTR is reduced by 6.06% on average compared with that of LRSR, which shows the effectiveness of introducing SDN centralized control;the packet loss rate of FTR is reduced by 25.79% compared with that of MLSR which also targets the minimum delay, which shows the effectiveness of temporary storage routing mechanism design for the Medium Earth Orbit(MEO) satellites. When the failure of nodes and links in the network is serious, FTR has the total routing delay 3.99% lower than LRSR and 19.19% lower than MLSR, and has the packet loss rate 16.94% lower than LRSR and 37.95% lower than MLSR, which shows the effectiveness of fault tolerance of FTR. The experimental results prove that the fault tolerant routing mechanism of satellite network based on SDN has better fault tolerant capability.