适于低轨卫星IP网络的特定源组播算法

为了解决低轨卫星IP网络中现有特定源组播算法的信道资源浪费问题,本文提出了一套新的特定源组播算法,即基于核心群的特定源组播算法(CSSM)和加权的CSSM算法(w-CSSM).CSSM算法以源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,所得的树代价最小,从而大大提高了网络的带宽利用率和传输效率.在w-CSSM算法中,加权因子可以自适应调整以适度增大树代价、降低端到端传播时延,以支持某些有严格端到端时延要求的实时组播业务.通过与低轨卫星IP网络中典型特定源组播算法MRA的仿真比较,可以看出CSSM和w-CSSM算法的树代价性能比MRA有较大改善,不过端到端传播时延略高.

Source-Specific Multicast Algorithms for LEO Satellite IP Networks

To resolve the channel resources waste problem of current source-specific multicast (SSM) routing algorithm in low earth orbit (LEO) satellite IP networks,a new SSM algorithm called core-cluster-based source-specific multicast (CSSM) algorithm and its improved one (the weighted CSSM algorithm) are presented.The CSSM algorithm takes source node as initial core-cluster,and extends it step by step to construct entire multicast tree with the lowest tree cost by a shortest path scheme between newly-generated core-cluster and surplus group member nodes,which can greatly improve transport bandwidth utilization and transport efficiency.In the w-CSSM algorithm,end-to-end propagation delay can be decreased and meanwhile tree cost will be increased a bit by adaptively adjusting the weighted coefficient to meet strict end-to-end delay requirements of some real-time multicast applications.Finally,performance comparison of the two algorithms with the typical SSM algorithm (i.e.MRA) in LEO satellite networks is provided.Simulation results show that their tree cost performance is greatly better than that of MRA at the expense of a bit higher end-to-end propagation delay.