适于低轨卫星IP网络的核心群合并共享树组播算法

The Core-Cluster Combination-Based Shared Tree Algorithm for LEO Satellite IP Networks

为了解决低轨卫星IP网络中现有典型源组播算法的信道资源浪费问题,该文提出了一种低树代价的组播算法,即核心群合并共享树(CCST)算法,包括动态近似中心(DAC)选核方法和核心群合并组播路径构建方法。DAC方法基于逻辑位置形成的虚拟静态、结构规则的网络拓扑选择核节点。在核心群合并方法中,以核节点作为初始核心群,通过核心群和剩余组成员的最短路径方法逐步扩展直至整棵组播树构建完成,从而使得组播树的树代价最小,大大提高了网络的传输带宽利用率和组播传输效率。最后,与低轨卫星IP网络中的其他几种典型算法进行了性能对比,仿真结果说明,CCST算法的树代价性能比其它算法有较大改善,而端到端传播时延略高。

To resolve the channel resources waste problem of the typical source-specific multicast routing algorithm in Low Earth Orbit （LEO） satellite IP networks, a new core-based shared tree algorithm named Core-cluster Combination-based Shared Tree （CCST） algorithm is proposed in this paper. It includes a core selection method named Dynamic Approximate Center （DAC） and a multicast route construction scheme named core-cluster combination. The DAC method selects core node based on virtually static and regular network topology formed by logical locations. The core-cluster combination scheme takes core node as initial core-cluster, and extends it to construct entire multicast tree with the lowest tree cost step by step by a shortest path scheme between newly-generated core-cluster and surplus group members, which can greatly improve transport bandwidth utilization and multicast transport efficiency. Finally, the CCST algorithm is compared with several other typical algorithms in LEO satellite IP networks, and simulation results show that its tree cost performance is greatly better than the others at the expense of a bit higher end-to-end propagation delay.