多层卫星网络的拓扑结构具有明显的时变特征,难以提供持续且稳定的端到端路径,导致高效路由问题面临着巨大的挑战.将卫星网络设计为封闭的体系结构,采用强管理或调度式控制策略会导致其无法自由、高效地实现与其它系统的协同组网.基于IP的网络体系结构在应用于多层卫星网络时又存在路由效率不高的问题.基于命名数据网络NDN(Named Data Networking)体系结构,提出一种多层卫星网络分布式路由方法——SNDN(Satellite Named Data Networking).根据链路切换的周期性和可预知性,以时变图为建模工具,设计一个能自适应稠密和稀疏场景的路由算法来动态地计算时间相关的最快路径并附加为源路由信息,充分利用命名数据网络数据驱动的通信模式、数据包级的安全特性和逐跳转发的特点,由节点在包转发的过程中动态地完成转发表(FIB,Forwarding Information Base)和请求状态表(PIT,Pending Interest Table)的构建.可为面向未来空、天、地一体化协同组网的多层卫星网络路由研究提供一种新的思路.通过仿真实验及对比分析,验证了SNDN在路由效率和多播性能方面的优势.%Efficient routing is a challenging problem in multi-layered satellite networks where the time-varying topology leads to the absence of continuous and stable paths.Most previous researches either leverage IP architecture to achieve addressing and routing which usually leads to poor routing efficiency in such dynamic scenarios or design specialized architecture by using scheduling based control strategy which makes it hard to achieve efficient cooperative networking with other systems.In this paper,we propose SNDN (Satellite Named Data Networking),a distributed routing method with high routing efficiency and multicast performance.Specifically,we construct two schemes to generate the rime varying FIB (Forwarding Information Base) and PIT (Pending Interest Table),and also design an efficient routing algorithm that can calculate the fastest timerelated routes under both dense and sparse scenarios by using a time varying graph method.Nodes can generate FIB/PIT or update the entries concurrently with packet forwarding either by extracting the source routing information that attached in the selectors field of packet header or calculating by themselves if needed.Extensive simulation results verify the efficiency and performance of SNDN and demonstrate that it is a useful attempt on the routing problem of multi-layered satellite networks.
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